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CompletedNCT00051363APPLESUpdated Nov 28, 2018Results posted

Apnea Positive Pressure Long-Term Efficacy Study

A Phase 3 interventional study of Active CPAP and Sham CPAP in Lung Diseases, Sleep Apnea Syndromes and Sleep, sponsored by Stanford University. Completed at 5 sites in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2018-11-28.

Sponsored by Stanford University · Phase 3, Interventional, and Treatment

Phase
Phase 3
Study type
Interventional
Enrollment
1,105
Allocation
Randomized
Ages
18 Years and older
Sex
All
01

Study summary

The purpose of this study is to determine the effectiveness of nasal continuous positive airway pressure (CPAP) therapy for the treatment of obstructive sleep apnea syndrome (OSAS).

Read the detailed description

BACKGROUND:

Nasal CPAP therapy is in widespread use as the primary treatment for OSAS, a sleep-related breathing disorder affecting more than 15 million Americans. The therapeutic effectiveness of CPAP in providing significant, stable, and long-term neurocognitive or other functional benefits to patients with OSAS has not been systematically investigated.

DESIGN NARRATIVE:

The study is a randomized, blinded, sham-controlled, multi-center trial of CPAP therapy. The principal aims of the study are: 1) to assess the long-term effectiveness of CPAP therapy on neurocognitive function, mood, sleepiness, and quality of life by administering tests of these indices to subjects randomly assigned to active or sham CPAP; 2) to identify specific neurocognitive deficits associated with OSAS in a large, heterogeneous subject population; 3) to determine which deficits in neurocognitive function in OSAS subjects are reversible and most sensitive to the effects of CPAP; 4) to develop a composite multivariate outcome measure from the results of this study that can be used to assess the clinical effectiveness of CPAP in improving neurocognitive function, mood, sleepiness, and quality of life; and 5) to use functional magnetic resonance imaging to compare cortical activation before and after CPAP therapy, and to assess whether this change is associated with improvement in specific neurocognitive task performance. The primary endpoint of the study is the effect of six months of CPAP treatment on neurocognitive function. A total of 1100 subjects (550 per treatment group) will be enrolled from the patient populations at five sites (Stanford University; University of Arizona; Brigham and Women's Hospital; Massachusetts; St. Luke's Hospital, Missouri; St. Mary Medical Center, Washington).

02

Conditions studied

  • Lung Diseases
  • Sleep Apnea Syndromes
  • Sleep

Keywords

  • Obstructive Sleep Apnea
03

In context

Apnea

1,422 studies on the registry are indexed under Apnea; 159 are open to participants now.

This study's enrollment of 1,105 is above the median of 50 across 965 interventional studies indexed under Apnea.

Browse Apnea studies →

Lead sponsor

Stanford University is the lead sponsor of 2,117 studies on the registry; 425 are open to participants now.

Of its 259 completed or terminated interventional studies of FDA-regulated products, 197 (76%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
No

Inclusion criteria

  • Male or female adults age 18 years or older with a diagnosis of OSAS using clinical criteria defined by the study protocol
  • Study participation may require seven or more laboratory visits over six months

Exclusion criteria

Exclusion Criteria:

  • Prior treatment for OSAS with continuous positive airway pressure or surgery
  • Potential sleep apnea complications that may affect the health or safety of the participant, including low blood oxygen, recent near-miss or prior automobile accident due to sleepiness, congestive heart failure, history of angina, coronary artery disease, myocardial infarction or stroke, cardiac rhythm disturbance, and chronic neurological disorders affecting neurocognitive abilities or daily function
  • The use of hypnotics, anxiolytics, sedating antidepressants, anticonvulsants, sedating antihistamines, stimulants or other medications likely to affect neurocognitive function and/or alertness
  • Respiratory disease requiring medications (unless on stable medications for 2 months)
  • Cancer, unless in remission for greater than one year and not taking exclusionary medications
  • Self-reported renal failure
  • Pregnancy anytime during a subject's participation
  • Psychiatric illness, as defined by a DSM-IV diagnosis, except for depression or mild anxiety
  • Narcolepsy, idiopathic hypersomnolence, DSM-IV chronic insomnia, restless legs syndrome, or rapid eye movement (REM) behavior disorder
  • Current use of diurnal or nocturnal supplemental oxygen
  • Significant vision, hearing, or coordination problems
  • Difficulty understanding or speaking English
  • Currently working night or rotating shifts
  • Consumption of more than 10 caffeinated beverages per day (approximately 1,000 mg per day)
  • Smokers whose habit interferes with the overnight polysomnogram or with the battery of testing during the day
  • Consumption of more than 2 alcoholic beverages per day
  • Any illicit drug usage or marijuana usage more than once a week
  • Any individual in the household currently on CPAP or on CPAP in the past
  • A score of 26 or less on the Mini Mental State Examination (MMSE)
05

Study design

Phase
Phase 3
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Quadruple (Participant, Care provider, Investigator, Outcomes assessor)
Enrollment
1,105 participants (actual)

Study arms

  • Active comparator
    Active CPAP

    Active Continuous Positive Airway Pressure (CPAP)

    Device: Active CPAP

  • Placebo comparator
    Sham CPAP

    Sham Continuous Positive Airway Pressure (CPAP)

    Device: Sham CPAP

Interventions

  • DeviceActive CPAP

    Nightly nasal continuous positive airway pressure (CPAP)

    Also known as: Positive Pressure Respiration

  • DeviceSham CPAP

    Sham CPAP machine will be used for participants in the placebo group.

    Also known as: Sham CPAP machine

06

What researchers measure

Primary outcomes

  1. Effect of CPAP on Neurocognitive Function: E/F Function- SWMT-OMD

    There are three primary measures of neurocognitive function measured for APPLES, each representing a different domain: Executive and Frontal-lobe (E/F) Function- Sustained Working Memory Test Overall Mid-Day Index (SWMT-OMD), Attention and Psychomotor (A/P) Function- Pathfinder Number Test Total Time (PFN-TOTL), and Learning and Memory (L/M) Function- Buschke Selective Reminding Test Sum Recall (BSRT-SR). This is domain #1: Executive and Frontal-lobe (E/F) Function- Sustained Working Memory Test Overall Mid-Day Index (SWMT-OMD) SWMT-OMD is a scaled score that indicates whether the participant scored lower or higher relative to baseline using standard deviation units. It is computed as the mean of three sub-scores, one based on working memory (WM) task performance (behavioral WM sub-score: speed, accuracy), and the other two on electroencephalogram (EEG) (cortical activation sub-score: neural workload, attentional effort during WM task; alertness sub-score: resting alertness).

    Time frame: 2 months and 6 months post intervention

  2. Effect of CPAP on Neurocognitive Function: A/P Function- PFN-TOTL

    There are three primary measures of neurocognitive function measured for APPLES, each representing a different domain: Executive and Frontal-lobe (E/F) Function- Sustained Working Memory Test Overall Mid-Day Index (SWMT-OMD), Attention and Psychomotor (A/P) Function- Pathfinder Number Test Total Time (PFN-TOTL), and Learning and Memory (L/M) Function- Buschke Selective Reminding Test Sum Recall (BSRT-SR). This is domain #2: Attention and Psychomotor (A/P) Function- Pathfinder Number Test Total Time (PFN-TOTL)

    Time frame: Measured at diagnostic visit (baseline) and 2 months and 6 months post intervention

  3. Effect of CPAP on Neurocognitive Function: L/M Function- BSRT-SR

    There are three primary measures of neurocognitive function measured for APPLES, each representing a different domain: Executive and Frontal-lobe (E/F) Function- Sustained Working Memory Test Overall Mid-Day Index (SWMT-OMD), Attention and Psychomotor (A/P) Function- Pathfinder Number Test Total Time (PFN-TOTL), and Learning and Memory (L/M) Function- Buschke Selective Reminding Test Sum Recall (BSRT-SR). This is domain #3: Learning and Memory (L/M) Function- Buschke Selective Reminding Test Sum Recall (BSRT-SR)

    Time frame: Measured at diagnostic visit (baseline) and 2 months and 6 months post intervention

Secondary outcomes

  1. Attention and Psychomotor (A/P) Function: Pathfinder Number- Reaction Time (PN-RT)

    The APPLES a priori Secondary Neurocognitive Analysis Plan specified a dimension reduction method to reduce twelve secondary neurocognitive variables from three neurocognitive domains to seven variables from three neurocognitive domains. Three of the selected variables came from the domain of Attention and Psychomotor (A/P) Function: Pathfinder Number- Reaction Time (PN-RT), Psychomotor Vigilance Task- Median Reaction Time (PVT-MedRT), and PVT- Mean Slowest 10% of Reaction Times (PVT-Slo10%RT). These data are for variable #1: Pathfinder Number- Reaction Time (PN-RT)

    Time frame: 2 months and 6 months post intervention

  2. Attention and Psychomotor (A/P) Function: Psychomotor Vigilance Task- Median Reaction Time (PVT-MedRT)

    The APPLES a priori Secondary Neurocognitive Analysis Plan specified a dimension reduction method to reduce twelve secondary neurocognitive variables from three neurocognitive domains to seven variables from three neurocognitive domains. Three of the selected variables came from the domain of Attention and Psychomotor (A/P) Function: Pathfinder Number- Reaction Time (PN-RT), Psychomotor Vigilance Task- Median Reaction Time (PVT-MedRT), and PVT- Mean Slowest 10% of Reaction Times (PVT-Slo10%RT). These data are for variable #2: Psychomotor Vigilance Task- Median Reaction Time (PVT-MedRT)

    Time frame: 2 months and 6 months post intervention

  3. Attention and Psychomotor (A/P) Function: PVT- Mean Slowest 10% of Reaction Times (PVT-Slo10%RT)

    The APPLES a priori Secondary Neurocognitive Analysis Plan specified a dimension reduction method to reduce twelve secondary neurocognitive variables from three neurocognitive domains to seven variables from three neurocognitive domains. Three of the selected variables came from the domain of Attention and Psychomotor (A/P) Function: Pathfinder Number- Reaction Time (PN-RT), Psychomotor Vigilance Task- Median Reaction Time (PVT-MedRT), and PVT- Mean Slowest 10% of Reaction Times (PVT-Slo10%RT). These data are for variable #3: PVT- Mean Slowest 10% of Reaction Times (PVT-Slo10%RT)

    Time frame: 2 months and 6 months post intervention

  4. Learning and Memory (L/M) Function: Buschke Selective Reminding Test Delayed Recall- Total Recall (BSRTDR-TotRec)

    The APPLES a priori Secondary Neurocognitive Analysis Plan specified a dimension reduction method to reduce twelve secondary neurocognitive variables from three neurocognitive domains to seven variables from three neurocognitive domains. One of the selected variables came from the domain of Learning and Memory (L/M) Function: Buschke Selective Reminding Test Delayed Recall- Total Recall (BSRTDR-TotRec).

    Time frame: 2 months and 6 months post intervention

  5. Executive and Frontal-Lobe (E/F) Function: Sustained Working Memory Test- Mid-day Behavioral Index (SWMT-BehMD)

    The APPLES a priori Secondary Neurocognitive Analysis Plan specified a dimension reduction method to reduce twelve secondary neurocognitive variables from three neurocognitive domains to seven variables from three neurocognitive domains. Three of the selected variables came from the domain of Executive and Frontal-Lobe (E/F) Function: SWMT-BehMD, SWMT-ActMD, and SAT-D-NumRuCh. These data are for variable #1: Sustained Working Memory Test- Mid-day Behavioral Index (SWMT-BehMD) SWMT-BehMD is a scaled score that indicates whether the participant scored lower or higher relative to baseline using standard deviation units. It is computed as the difference from baseline relative to measures of working memory (WM) task performance accuracy (percent correct) and mean and standard deviation of reaction time (milliseconds). High-load WM tasks receive twice the weight of the low-load WM tasks.

    Time frame: 2 months and 6 months post intervention

  6. Executive and Frontal-Lobe (E/F) Function: SWMT- Mid-day Activation Index (SWMT-ActMD)

    The APPLES a priori Secondary Neurocognitive Analysis Plan specified a dimension reduction method to reduce twelve secondary neurocognitive variables from three neurocognitive domains to seven variables from three neurocognitive domains. Three of the selected variables came from the domain of Executive and Frontal-Lobe (E/F) Function: SWMT-BehMD, SWMT-ActMD, and SAT-D-NumRuCh. These data are for variable #2: SWMT- Mid-day Activation Index (SWMT-ActMD) SWMT-ActMD is a scaled score that indicates whether the participant scored lower or higher relative to baseline (BL) using standard deviation units. It is computed as the difference from BL relative to EEG power spectral variables (decibels) measured during the easier vs. more difficult working memory (WM) tasks. A positive activation sub-score indicates a larger cortical neuronal population was recruited to perform the more difficult WM task relative to BL, while a negative score indicates a smaller population was recruited.

    Time frame: 2 months and 6 months post intervention

  7. Executive and Frontal-Lobe (E/F) Function: Shifting Attention Test Discovery Condition- Number of Rule Changes (SAT-D-NumRuCh)

    The APPLES a priori Secondary Neurocognitive Analysis Plan specified a dimension reduction method to reduce twelve secondary neurocognitive variables from three neurocognitive domains to seven variables from three neurocognitive domains. Three of the selected variables came from the domain of Executive and Frontal-Lobe (E/F) Function: Sustained Working Memory Test- Mid-day Behavioral Index (SWMT-BehMD), SWMT- Mid-day Activation Index (SWMT-ActMD), and Shifting Attention Test Discovery Condition- Number of Rule Changes (SAT-D-NumRuCh). These data are for variable #3: Shifting Attention Test Discovery Condition- Number of Rule Changes (SAT-D-NumRuCh)

    Time frame: 2 months and 6 months post intervention

  8. Objective Sleepiness/Alertness: Maintenance of Wakefulness Test- Mean Sleep Latency (MWT-MSL)

    Objective sleepiness/alertness was measured using the Maintenance of Wakefulness Test (MWT); the outcome variable was MWT Mean Sleep Latency (MWT-MSL). The MWT was administered using four twenty-minute trials where the participant was asked to sit in a chair, in a quiet and dimly lit room, with instructions to stay awake. Trials were performed at 10 AM, Noon, 2 PM and 4 PM. The mean sleep latency was calculated using the 4 trials from a given visit, and required that at least 3 of the 4 trials were performed and validated.

    Time frame: Measured at diagnostic visit (baseline) and 2 months and 6 months post intervention

  9. Subjective Sleepiness/Alertness: Epworth Sleepiness Scale- Total Score (ESS-TS)

    Subjective sleepiness/alertness was measured using the Epworth Sleepiness Scale (ESS); the outcome variable was ESS Total Score (ESS-TS). The ESS is a validated questionnaire (8 questions) that ask the chances of dozing off in specific situations. Summing the scores produces a scaled total score between 0 and 24, with higher numbers indicating more subjective sleepiness. The ESS was administered the evening before the polysomnogram (PSG), or overnight sleep study. Data reported here include questionnaires collected at the DX, 2M, and 6M visits.

    Time frame: Measured at diagnostic visit (baseline) and 2 months and 6 months post intervention

  10. Mood

    Time frame: Measured at diagnostic visit (baseline) and 2 months and 6 months post intervention

  11. Quality of Life: Calgary Sleep Apnea Quality of Life Index- Total Score (SAQLI-TS)

    Quality of life was measured using the Calgary Sleep Apnea Quality of Life Index (SAQLI), which is an interview-administered instrument with high internal consistency and reliability. The SAQLI was designed to assess components identified as important to patients including daily functioning, social interactions, emotional functioning, symptoms experienced, and treatment-related symptoms. Items are scored on a seven-point scale, averaged (taking into account treatment-related symptoms), to yield a composite score between 1 and 7, where higher scores represent better quality of life.

    Time frame: diagnostic visit (baseline)

Other outcomes

  1. Functional Magnetic Resonance Imaging (fMRI)

    Time frame: Measured at diagnostic visit (baseline) and 6 months post intervention

07

Results

Posted Nov 30, 2016
Limitations and caveats
There are study sample limitations because although participants with severe OSA were included, those who had the lowest oxygen saturation, a history of sleepiness-related accidents, or major cardiovascular comorbidities were excluded.

Participant flow

Participant flow — Overall Study
MilestoneActive CPAPSham CPAP
Started558547
Randomized & analyzed556542
Completed 2m visit on-treatment456417
Completed 2m visit on-study468432
Completed 6m visit on-treatment427372
Completed 6m vist on-study443403
Completed443403
Not completed115144
Withdrew: Dropped post-rand for any reason102126
Withdrew: Disqualified post-rand for any reason911
Withdrew: Death22
Withdrew: Excluded pre-randomization25

Outcome measures

PrimaryEffect of CPAP on Neurocognitive Function: E/F Function- SWMT-OMD

There are three primary measures of neurocognitive function measured for APPLES, each representing a different domain: Executive and Frontal-lobe (E/F) Function- Sustained Working Memory Test Overall Mid-Day Index (SWMT-OMD), Attention and Psychomotor (A/P) Function- Pathfinder Number Test Total Time (PFN-TOTL), and Learning and Memory (L/M) Function- Buschke Selective Reminding Test Sum Recall (BSRT-SR). This is domain #1: Executive and Frontal-lobe (E/F) Function- Sustained Working Memory Test Overall Mid-Day Index (SWMT-OMD) SWMT-OMD is a scaled score that indicates whether the participant scored lower or higher relative to baseline using standard deviation units. It is computed as the mean of three sub-scores, one based on working memory (WM) task performance (behavioral WM sub-score: speed, accuracy), and the other two on electroencephalogram (EEG) (cortical activation sub-score: neural workload, attentional effort during WM task; alertness sub-score: resting alertness).

Time frame:
2 months and 6 months post intervention
Reported as:
Mean · score on a scale
Effect of CPAP on Neurocognitive Function: E/F Function- SWMT-OMD
score on a scaleActive CPAPSham CPAP
SWMT-OMD 2M0.035 (-0.019 to 0.090)-0.074 (-0.133 to -0.015)
SWMT-OMD 6M0.072 (0.012 to 0.132)0.018 (-0.046 to 0.082)
Statistical analysis
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.0074 (2M E/F Function- SWMT-OMD; P\<0.0307 indicates statistical significance for raw P values (after adjustment for O'Brien-Fleming spending across 3 interim analyses). After correction for multiple comparisons (sequential Bonferroni) P Value=0.0444 (NS))Generalized Linear Models (GLM) were run by visit (2M and 6M).
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.2254 (6M E/F Function- SWMT-OMD; P\<0.0307 indicates statistical significance for raw P values (after adjustment for O'Brien-Fleming spending across 3 interim analyses).)Generalized Linear Models (GLM) were run by visit (2M and 6M).
PrimaryEffect of CPAP on Neurocognitive Function: A/P Function- PFN-TOTL

There are three primary measures of neurocognitive function measured for APPLES, each representing a different domain: Executive and Frontal-lobe (E/F) Function- Sustained Working Memory Test Overall Mid-Day Index (SWMT-OMD), Attention and Psychomotor (A/P) Function- Pathfinder Number Test Total Time (PFN-TOTL), and Learning and Memory (L/M) Function- Buschke Selective Reminding Test Sum Recall (BSRT-SR). This is domain #2: Attention and Psychomotor (A/P) Function- Pathfinder Number Test Total Time (PFN-TOTL)

Time frame:
Measured at diagnostic visit (baseline) and 2 months and 6 months post intervention
Reported as:
Mean · seconds
Effect of CPAP on Neurocognitive Function: A/P Function- PFN-TOTL
secondsActive CPAPSham CPAP
PFN-TOTL Dx23.32 (22.88 to 23.78)23.08 (22.64 to 23.54)
PFN-TOTL 2M23.56 (23.05 to 24.10)22.92 (22.41 to 23.45)
PFN-TOTL 6M23.48 (22.98 to 24.00)23.01 (22.51 to 23.54)
Statistical analysis
  • Active CPAP vs Sham CPAP · Parametric survival analysis · p = 0.4538 (DX A/P Function- PFN-TOTL; P\<0.0307 indicates statistical significance for raw P values (after adjustment for O'Brien-Fleming spending across 3 interim analyses).)Parametric survival analyses were conducted using by-visit comparisons for A/P Function- PFN-TOTL since these data were right censored at 60.
  • Active CPAP vs Sham CPAP · Parametric survival analysis · p = 0.0860 (2M A/P Function- PFN-TOTL; P\<0.0307 indicates statistical significance for raw P values (after adjustment for O'Brien-Fleming spending across 3 interim analyses).)Parametric survival analyses were conducted using by-visit comparisons for A/P Function- PFN-TOTL since these data were right censored at 60.
  • Active CPAP vs Sham CPAP · Parametric survival analysis · p = 0.2103 (6M A/P Function- PFN-TOTL; P\<0.0307 indicates statistical significance for raw P values (after adjustment for O'Brien-Fleming spending across 3 interim analyses).)Parametric survival analyses were conducted using by-visit comparisons for A/P Function- PFN-TOTL since these data were right censored at 60.
PrimaryEffect of CPAP on Neurocognitive Function: L/M Function- BSRT-SR

There are three primary measures of neurocognitive function measured for APPLES, each representing a different domain: Executive and Frontal-lobe (E/F) Function- Sustained Working Memory Test Overall Mid-Day Index (SWMT-OMD), Attention and Psychomotor (A/P) Function- Pathfinder Number Test Total Time (PFN-TOTL), and Learning and Memory (L/M) Function- Buschke Selective Reminding Test Sum Recall (BSRT-SR). This is domain #3: Learning and Memory (L/M) Function- Buschke Selective Reminding Test Sum Recall (BSRT-SR)

Time frame:
Measured at diagnostic visit (baseline) and 2 months and 6 months post intervention
Reported as:
Mean · number of words recalled
Effect of CPAP on Neurocognitive Function: L/M Function- BSRT-SR
number of words recalledActive CPAPSham CPAP
BSRT-SR Dx49.72 (48.95 to 50.48)49.86 (49.09 to 50.64)
BSRT-SR 2M52.32 (51.50 to 53.13)51.95 (51.10 to 52.80)
BSRT-SR 6M54.09 (53.26 to 54.91)54.28 (53.41 to 55.13)
Statistical analysis
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.7936 (DX L/M Function- BSRT-SR; P\<0.0307 indicates statistical significance for raw P values (after adjustment for O'Brien-Fleming spending across 3 interim analyses).)Generalized Linear Models (GLM) were run by visit (2M and 6M).
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.5444 (2M L/M Function- BSRT-SR; P\<0.0307 indicates statistical significance for raw P values (after adjustment for O'Brien-Fleming spending across 3 interim analyses).)Generalized Linear Models (GLM) were run by visit (2M and 6M).
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.7569 (6M L/M Function- BSRT-SR; P\<0.0307 indicates statistical significance for raw P values (after adjustment for O'Brien-Fleming spending across 3 interim analyses).)Generalized Linear Models (GLM) were run by visit (2M and 6M).
SecondaryAttention and Psychomotor (A/P) Function: Pathfinder Number- Reaction Time (PN-RT)

The APPLES a priori Secondary Neurocognitive Analysis Plan specified a dimension reduction method to reduce twelve secondary neurocognitive variables from three neurocognitive domains to seven variables from three neurocognitive domains. Three of the selected variables came from the domain of Attention and Psychomotor (A/P) Function: Pathfinder Number- Reaction Time (PN-RT), Psychomotor Vigilance Task- Median Reaction Time (PVT-MedRT), and PVT- Mean Slowest 10% of Reaction Times (PVT-Slo10%RT). These data are for variable #1: Pathfinder Number- Reaction Time (PN-RT)

Time frame:
2 months and 6 months post intervention
Reported as:
Mean · seconds
Attention and Psychomotor (A/P) Function: Pathfinder Number- Reaction Time (PN-RT)
secondsActive CPAPSham CPAP
2M PN-RT Mild OSA0.811 (0.785 to 0.839)0.801 (0.774 to 0.830)
2M PN-RT Moderate OSA0.831 (0.811 to 0.852)0.825 (0.806 to 0.845)
2M PN-RT Severe OSA0.818 (0.802 to 0.834)0.812 (0.797 to 0.828)
6M PN-RT Mild OSA0.811 (0.784 to 0.839)0.795 (0.767 to 0.826)
6M PN-RT Moderate OSA0.830 (0.808 to 0.853)0.819 (0.799 to 0.841)
6M PN-RT Severe OSA0.817 (0.800 to 0.836)0.806 (0.790 to 0.823)
Statistical analysis
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.5606 (2M L/M Function- PN-RT (Mild OSA); P\<0.05 indicates statistical significance for P values. Data were reciprocal transformed for analysis and back-transformed for reporting.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.6487 (2M L/M Function- PN-RT (Moderate OSA); P\<0.05 indicates statistical significance for P values. Data were reciprocal transformed for analysis and back-transformed for reporting.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.5667 (2M L/M Function- PN-RT (Severe OSA); P\<0.05 indicates statistical significance for P values. Data were reciprocal transformed for analysis and back-transformed for reporting.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.3972 (6M L/M Function- PN-RT (Mild OSA); P\<0.05 indicates statistical significance for P values. Data were reciprocal transformed for analysis and back-transformed for reporting.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.3973 (6M L/M Function- PN-RT (Moderate OSA); P\<0.05 indicates statistical significance for P values. Data were reciprocal transformed for analysis and back-transformed for reporting.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.3055 (6M L/M Function- PN-RT (Moderate OSA); P\<0.05 indicates statistical significance for P values. Data were reciprocal transformed for analysis and back-transformed for reporting.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
SecondaryAttention and Psychomotor (A/P) Function: Psychomotor Vigilance Task- Median Reaction Time (PVT-MedRT)

The APPLES a priori Secondary Neurocognitive Analysis Plan specified a dimension reduction method to reduce twelve secondary neurocognitive variables from three neurocognitive domains to seven variables from three neurocognitive domains. Three of the selected variables came from the domain of Attention and Psychomotor (A/P) Function: Pathfinder Number- Reaction Time (PN-RT), Psychomotor Vigilance Task- Median Reaction Time (PVT-MedRT), and PVT- Mean Slowest 10% of Reaction Times (PVT-Slo10%RT). These data are for variable #2: Psychomotor Vigilance Task- Median Reaction Time (PVT-MedRT)

Time frame:
2 months and 6 months post intervention
Reported as:
Mean · milliseconds
Attention and Psychomotor (A/P) Function: Psychomotor Vigilance Task- Median Reaction Time (PVT-MedRT)
millisecondsActive CPAPSham CPAP
2M PVT-MedRT Mild OSA245.31 (230.94 to 260.58)253.89 (238.02 to 270.82)
2M PVT-MedRT Moderate OSA248.68 (237.96 to 259.89)248.94 (237.99 to 260.40)
2M PVT-MedRT Severe OSA243.25 (235.36 to 251.41)247.55 (238.79 to 256.62)
6M PVT-MedRT Mild OSA245.23 (230.20 to 261.23)254.05 (237.26 to 272.03)
6M PVT-MedRT Moderate OSA248.60 (236.74 to 261.04)249.10 (236.95 to 261.86)
6M PVT-MedRT Severe OSA243.17 (234.05 to 252.64)247.70 (237.46 to 258.38)
Statistical analysis
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.3699 (2M A/P Function- PVT-MedRT (Mild OSA); P\<0.05 indicates statistical significance for P values. Data were reciprocal transformed for analysis and back-transformed for reporting.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.9673 (2M A/P Function- PVT-MedRT (Moderate OSA); P\<0.05 indicates statistical significance for P values. Data were reciprocal transformed for analysis and back-transformed for reporting.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.3426 (2M A/P Function- PVT-MedRT (Severe OSA); P\<0.05 indicates statistical significance for P values. Data were reciprocal transformed for analysis and back-transformed for reporting.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.3901 (6M A/P Function- PVT-MedRT (Mild OSA); P\<0.05 indicates statistical significance for P values. Data were reciprocal transformed for analysis and back-transformed for reporting.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.9464 (6M A/P Function- PVT-MedRT (Moderate OSA); P\<0.05 indicates statistical significance for P values. Data were reciprocal transformed for analysis and back-transformed for reporting.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.4372 (6M A/P Function- PVT-MedRT (Severe OSA); P\<0.05 indicates statistical significance for P values. Data were reciprocal transformed for analysis and back-transformed for reporting.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
SecondaryAttention and Psychomotor (A/P) Function: PVT- Mean Slowest 10% of Reaction Times (PVT-Slo10%RT)

The APPLES a priori Secondary Neurocognitive Analysis Plan specified a dimension reduction method to reduce twelve secondary neurocognitive variables from three neurocognitive domains to seven variables from three neurocognitive domains. Three of the selected variables came from the domain of Attention and Psychomotor (A/P) Function: Pathfinder Number- Reaction Time (PN-RT), Psychomotor Vigilance Task- Median Reaction Time (PVT-MedRT), and PVT- Mean Slowest 10% of Reaction Times (PVT-Slo10%RT). These data are for variable #3: PVT- Mean Slowest 10% of Reaction Times (PVT-Slo10%RT)

Time frame:
2 months and 6 months post intervention
Reported as:
Mean · milliseconds
Attention and Psychomotor (A/P) Function: PVT- Mean Slowest 10% of Reaction Times (PVT-Slo10%RT)
millisecondsActive CPAPSham CPAP
2M PVT-Slo10%RT Mild OSA403.00 (375.99 to 431.95)402.32 (376.77 to 429.62)
2M PVT-Slo10%RT Moderate OSA412.44 (390.91 to 435.16)407.84 (387.67 to 429.06)
2M PVT-Slo10%RT Severe OSA400.57 (384.51 to 417.30)406.11 (387.05 to 426.07)
6M PVT-Slo10%RT Mild OSA396.87 (370.79 to 424.79)401.28 (375.51 to 428.82)
6M PVT-Slo10%RT Moderate OSA406.17 (383.96 to 429.66)406.78 (385.63 to 429.09)
6M PVT-Slo10%RT Severe OSA394.48 (377.66 to 412.05)405.04 (384.90 to 426.24)
Statistical analysis
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.9656 (2M A/P Function- PVT-Slo10%RT (Mild OSA); P\<0.05 indicates statistical significance for P values. Data were reciprocal transformed for analysis and back-transformed for reporting.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.6765 (2M A/P Function- PVT-Slo10%RT (Moderate OSA); P\<0.05 indicates statistical significance for P values. Data were reciprocal transformed for analysis and back-transformed for reporting.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.5288 (2M A/P Function- PVT-Slo10%RT (Severe OSA); P\<0.05 indicates statistical significance for P values. Data were reciprocal transformed for analysis and back-transformed for reporting.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.7807 (6M A/P Function- PVT-Slo10%RT (Mild OSA); P\<0.05 indicates statistical significance for P values. Data were reciprocal transformed for analysis and back-transformed for reporting.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.9603 (6M A/P Function- PVT-Slo10%RT (Moderate OSA); P\<0.05 indicates statistical significance for P values. Data were reciprocal transformed for analysis and back-transformed for reporting.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.3075 (6M A/P Function- PVT-Slo10%RT (Severe OSA); P\<0.05 indicates statistical significance for P values. Data were reciprocal transformed for analysis and back-transformed for reporting.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
SecondaryLearning and Memory (L/M) Function: Buschke Selective Reminding Test Delayed Recall- Total Recall (BSRTDR-TotRec)

The APPLES a priori Secondary Neurocognitive Analysis Plan specified a dimension reduction method to reduce twelve secondary neurocognitive variables from three neurocognitive domains to seven variables from three neurocognitive domains. One of the selected variables came from the domain of Learning and Memory (L/M) Function: Buschke Selective Reminding Test Delayed Recall- Total Recall (BSRTDR-TotRec).

Time frame:
2 months and 6 months post intervention
Reported as:
Mean · number of words recalled
Learning and Memory (L/M) Function: Buschke Selective Reminding Test Delayed Recall- Total Recall (BSRTDR-TotRec)
number of words recalledActive CPAPSham CPAP
2M BSRTDR-TotRec Mild OSA8.54 (7.99 to 9.10)8.20 (7.53 to 8.87)
2M BSRTDR-TotRec Moderate OSA8.49 (8.13 to 8.85)8.22 (7.82 to 8.62)
2M BSRTDR-TotRec Severe OSA8.48 (8.20 to 8.76)8.21 (7.92 to 8.51)
6M BSRTDR-TotRec Mild OSA9.01 (8.47 to 9.54)9.44 (8.92 to 9.97)
6M BSRTDR-TotRec Moderate OSA8.56 (8.14 to 8.98)8.91 (8.54 to 9.28)
6M BSRTDR-TotRec Severe OSA8.87 (8.58 to 9.16)8.75 (8.48 to 9.01)
Statistical analysis
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.4262 (2M L/M Function- BSRTDR-TotRec (Mild OSA); P\<0.05 indicates statistical significance for P values.)Generalized Linear Models (GLM) were run by visit (2M and 6M).
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.3161 (2M L/M Function- BSRTDR-TotRec (Moderate OSA); P\<0.05 indicates statistical significance for P values.)Generalized Linear Models (GLM) were run by visit (2M and 6M).
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.1835 (2M L/M Function- BSRTDR-TotRec (Severe OSA); P\<0.05 indicates statistical significance for P values.)Generalized Linear Models (GLM) were run by visit (2M and 6M).
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.2462 (6M L/M Function- BSRTDR-TotRec (Mild OSA); P\<0.05 indicates statistical significance for P values.)Generalized Linear Models (GLM) were run by visit (2M and 6M).
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.2069 (6M L/M Function- BSRTDR-TotRec (Moderate OSA); P\<0.05 indicates statistical significance for P values.)Generalized Linear Models (GLM) were run by visit (2M and 6M).
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.5235 (6M L/M Function- BSRTDR-TotRec (Severe OSA); P\<0.05 indicates statistical significance for P values.)Generalized Linear Models (GLM) were run by visit (2M and 6M).
SecondaryExecutive and Frontal-Lobe (E/F) Function: Sustained Working Memory Test- Mid-day Behavioral Index (SWMT-BehMD)

The APPLES a priori Secondary Neurocognitive Analysis Plan specified a dimension reduction method to reduce twelve secondary neurocognitive variables from three neurocognitive domains to seven variables from three neurocognitive domains. Three of the selected variables came from the domain of Executive and Frontal-Lobe (E/F) Function: SWMT-BehMD, SWMT-ActMD, and SAT-D-NumRuCh. These data are for variable #1: Sustained Working Memory Test- Mid-day Behavioral Index (SWMT-BehMD) SWMT-BehMD is a scaled score that indicates whether the participant scored lower or higher relative to baseline using standard deviation units. It is computed as the difference from baseline relative to measures of working memory (WM) task performance accuracy (percent correct) and mean and standard deviation of reaction time (milliseconds). High-load WM tasks receive twice the weight of the low-load WM tasks.

Time frame:
2 months and 6 months post intervention
Reported as:
Mean · score on a scale
Executive and Frontal-Lobe (E/F) Function: Sustained Working Memory Test- Mid-day Behavioral Index (SWMT-BehMD)
score on a scaleActive CPAPSham CPAP
2M SWMT-BehMD Mild OSA0.180 (0.006 to 0.355)0.104 (-0.074 to 0.283)
2M SWMT-BehMD Moderate OSA0.137 (0.035 to 0.238)0.126 (0.007 to 0.245)
2M SWMT-BehMD Severe OSA0.205 (0.117 to 0.294)-0.011 (-0.128 to 0.106)
6M SWMT-BehMD Mild0.143 (-0.072 to 0.357)0.116 (-0.123 to 0.356)
6M SWMT-BehMD Moderate OSA0.194 (0.062 to 0.325)0.314 (0.191 to 0.437)
6M SWMT-BehMD Severe OSA0.321 (0.212 to 0.430)0.173 (0.052 to 0.295)
Statistical analysis
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.5419 (2M E/F Function- SWMT-BehMD (Mild OSA); P\<0.05 indicates statistical significance for P values.)Generalized Linear Models (GLM) were run by visit (2M and 6M).
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.8900 (2M E/F Function- SWMT-BehMD (Moderate OSA); P\<0.05 indicates statistical significance for P values.)Generalized Linear Models (GLM) were run by visit (2M and 6M).
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.0031 (2M E/F Function- SWMT-BehMD (Severe OSA); P\<0.05 indicates statistical significance for P values.)Generalized Linear Models (GLM) were run by visit (2M and 6M).
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.8703 (6M E/F Function- SWMT-BehMD (Mild OSA); P\<0.05 indicates statistical significance for P values.)Generalized Linear Models (GLM) were run by visit (2M and 6M).
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.1838 (6M E/F Function- SWMT-BehMD (Moderate OSA); P\<0.05 indicates statistical significance for P values.)Generalized Linear Models (GLM) were run by visit (2M and 6M).
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.0739 (6M E/F Function- SWMT-BehMD (Severe OSA); P\<0.05 indicates statistical significance for P values.)Generalized Linear Models (GLM) were run by visit (2M and 6M).
SecondaryExecutive and Frontal-Lobe (E/F) Function: SWMT- Mid-day Activation Index (SWMT-ActMD)

The APPLES a priori Secondary Neurocognitive Analysis Plan specified a dimension reduction method to reduce twelve secondary neurocognitive variables from three neurocognitive domains to seven variables from three neurocognitive domains. Three of the selected variables came from the domain of Executive and Frontal-Lobe (E/F) Function: SWMT-BehMD, SWMT-ActMD, and SAT-D-NumRuCh. These data are for variable #2: SWMT- Mid-day Activation Index (SWMT-ActMD) SWMT-ActMD is a scaled score that indicates whether the participant scored lower or higher relative to baseline (BL) using standard deviation units. It is computed as the difference from BL relative to EEG power spectral variables (decibels) measured during the easier vs. more difficult working memory (WM) tasks. A positive activation sub-score indicates a larger cortical neuronal population was recruited to perform the more difficult WM task relative to BL, while a negative score indicates a smaller population was recruited.

Time frame:
2 months and 6 months post intervention
Reported as:
Mean · score on a scale
Executive and Frontal-Lobe (E/F) Function: SWMT- Mid-day Activation Index (SWMT-ActMD)
score on a scaleActive CPAPSham CPAP
2M SWMT-ActMD Mild-0.050 (-0.268 to 0.169)0.317 (0.031 to 0.603)
2M SWMT-ActMD Moderate OSA0.262 (0.084 to 0.440)0.170 (0.006 to 0.334)
2M SWMT-ActMD Severe OSA-0.003 (-0.109 to 0.103)0.033 (-0.093 to 0.159)
6M SWMT-ActMD Mild0.157 (-0.089 to 0.403)0.118 (-0.117 to 0.353)
6M SWMT-ActMD Moderate OSA0.016 (-0.131 to 0.162)0.014 (-0.188 to 0.216)
6M SWMT-ActMD Severe OSA0.058 (-0.068 to 0.185)0.123 (-0.016 to 0.262)
Statistical analysis
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.0450 (2M E/F Function- SWMT-ActMD (Mild OSA); P\<0.05 indicates statistical significance for P values.)Generalized Linear Models (GLM) were run by visit (2M and 6M).
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.4512 (2M E/F Function- SWMT-ActMD (Moderate OSA); P\<0.05 indicates statistical significance for P values.)Generalized Linear Models (GLM) were run by visit (2M and 6M).
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.6672 (2M E/F Function- SWMT-ActMD (Severe OSA); P\<0.05 indicates statistical significance for P values.)Generalized Linear Models (GLM) were run by visit (2M and 6M).
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.8197 (6M E/F Function- SWMT-ActMD (Mild OSA); P\<0.05 indicates statistical significance for P values.)Generalized Linear Models (GLM) were run by visit (2M and 6M).
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.9890 (6M E/F Function- SWMT-ActMD (Moderate OSA); P\<0.05 indicates statistical significance for P values.)Generalized Linear Models (GLM) were run by visit (2M and 6M).
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.5029 (6M E/F Function- SWMT-ActMD (Severe OSA); P\<0.05 indicates statistical significance for P values.)Generalized Linear Models (GLM) were run by visit (2M and 6M).
SecondaryExecutive and Frontal-Lobe (E/F) Function: Shifting Attention Test Discovery Condition- Number of Rule Changes (SAT-D-NumRuCh)

The APPLES a priori Secondary Neurocognitive Analysis Plan specified a dimension reduction method to reduce twelve secondary neurocognitive variables from three neurocognitive domains to seven variables from three neurocognitive domains. Three of the selected variables came from the domain of Executive and Frontal-Lobe (E/F) Function: Sustained Working Memory Test- Mid-day Behavioral Index (SWMT-BehMD), SWMT- Mid-day Activation Index (SWMT-ActMD), and Shifting Attention Test Discovery Condition- Number of Rule Changes (SAT-D-NumRuCh). These data are for variable #3: Shifting Attention Test Discovery Condition- Number of Rule Changes (SAT-D-NumRuCh)

Time frame:
2 months and 6 months post intervention
Reported as:
Mean · number of rule changes (dichotomized)
Executive and Frontal-Lobe (E/F) Function: Shifting Attention Test Discovery Condition- Number of Rule Changes (SAT-D-NumRuCh)
number of rule changes (dichotomized)Active CPAPSham CPAP
2M SAT-D-NumRuCh Mild OSA0.931 (0.885 to 0.977)0.929 (0.873 to 0.985)
2M SAT-D-NumRuCh Moderate OSA0.936 (0.904 to 0.968)0.951 (0.924 to 0.979)
2M SAT-D-NumRuCh Severe OSA0.952 (0.931 to 0.972)0.942 (0.918 to 0.967)
6M SAT-D-NumRuCh Mild0.897 (0.827 to 0.966)0.907 (0.832 to 0.982)
6M SAT-D-NumRuCh Moderate OSA0.903 (0.853 to 0.953)0.935 (0.896 to 0.975)
6M SAT-D-NumRuCh Severe OSA0.927 (0.894 to 0.959)0.924 (0.888 to 0.960)
Statistical analysis
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.9518 (2M E/F Function- SAT-D-NumRuCh (Mild OSA); P\<0.05 indicates statistical significance for P values. Outcome formulated as dichotomized variable (\<=2 vs. \>=3) based on a 5th percentile cut-off used in pilot studies per test developer suggestion.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.4108 (2M E/F Function- SAT-D-NumRuCh (Moderate OSA); P\<0.05 indicates statistical significance for P values. Outcome formulated as dichotomized variable (\<=2 vs. \>=3) based on a 5th percentile cut-off used in pilot studies per test developer suggestion.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.4528 (2M E/F Function- SAT-D-NumRuCh (Severe OSA); P\<0.05 indicates statistical significance for P values. Outcome formulated as dichotomized variable (\<=2 vs. \>=3) based on a 5th percentile cut-off used in pilot studies per test developer suggestion.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.8391 (6M E/F Function- SAT-D-NumRuCh (Mild OSA); P\<0.05 indicates statistical significance for P values. Outcome formulated as dichotomized variable (\<=2 vs. \>=3) based on a 5th percentile cut-off used in pilot studies per test developer suggestion.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.2771 (6M E/F Function- SAT-D-NumRuCh (Moderate OSA); P\<0.05 indicates statistical significance for P values. Outcome formulated as dichotomized variable (\<=2 vs. \>=3) based on a 5th percentile cut-off used in pilot studies per test developer suggestion.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
  • Active CPAP vs Sham CPAP · Mixed Models Analysis · p = 0.8961 (6M E/F Function- SAT-D-NumRuCh (Severe OSA); P\<0.05 indicates statistical significance for P values. Outcome formulated as dichotomized variable (\<=2 vs. \>=3) based on a 5th percentile cut-off used in pilot studies per test developer suggestion.)Generalized Linear Mixed Models (GLMM) were utilized to account for repeated measures (DX, 2M, 6M).
SecondaryObjective Sleepiness/Alertness: Maintenance of Wakefulness Test- Mean Sleep Latency (MWT-MSL)

Objective sleepiness/alertness was measured using the Maintenance of Wakefulness Test (MWT); the outcome variable was MWT Mean Sleep Latency (MWT-MSL). The MWT was administered using four twenty-minute trials where the participant was asked to sit in a chair, in a quiet and dimly lit room, with instructions to stay awake. Trials were performed at 10 AM, Noon, 2 PM and 4 PM. The mean sleep latency was calculated using the 4 trials from a given visit, and required that at least 3 of the 4 trials were performed and validated.

Time frame:
Measured at diagnostic visit (baseline) and 2 months and 6 months post intervention
Reported as:
Mean · minutes
Objective Sleepiness/Alertness: Maintenance of Wakefulness Test- Mean Sleep Latency (MWT-MSL)
minutesActive CPAPSham CPAP
DX MWT-MSL17.13 ± 3.8616.95 ± 4.13
DX MWT-MSL Mild OSA17.51 ± 3.7117.62 ± 3.38
DX MWT-MSL Moderate OSA17.74 ± 3.5017.76 ± 3.68
DX MWT-MSL Severe OSA16.68 ± 4.0516.35 ± 4.43
2M MWT-MSL17.96 ± 3.4017.27 ± 3.89
2M MWT-MSL Mild OSA17.52 ± 3.6018.21 ± 2.94
2M MWT-MSL Moderate OSA17.91 ± 3.3918.14 ± 2.93
2M MWT-MSL Severe OSA18.10 ± 3.3516.63 ± 4.34
6M MWT-MSL18.11 ± 3.2717.34 ± 3.82
6M MWT-MSL Mild OSA17.77 ± 4.0017.89 ± 3.27
6M MWT-MSL Moderate OSA17.90 ± 3.4118.18 ± 3.27
6M MWT-MSL Severe OSA18.30 ± 2.9816.78 ± 4.10
Statistical analysis
  • Active CPAP vs Sham CPAP · Chop-lump Wilcoxon · p = 0.6540 (DX- MWT-MSL; Comparison of means by visit only; P\<0.05 indicates statistical significance for P values.)Chop-lump test was selected due to a high frequency of scores at the twenty-minute ceiling.
  • Active CPAP vs Sham CPAP · Chop-lump Wilcoxon · p = 0.9778 (DX- MWT-MSL (Mild OSA); Comparison of means by visit and Obstructive Sleep Apnea (OSA) severity; P\<0.05 indicates statistical significance for P values.)Chop-lump test was selected due to a high frequency of scores at the twenty-minute ceiling.
  • Active CPAP vs Sham CPAP · Chop-lump Wilcoxon · p = 0.8314 (DX- MWT-MSL (Moderate OSA); Comparison of means by visit and Obstructive Sleep Apnea (OSA) severity; P\<0.05 indicates statistical significance for P values.)Chop-lump test was selected due to a high frequency of scores at the twenty-minute ceiling.
  • Active CPAP vs Sham CPAP · Chop-lump Wilcoxon · p = 0.5018 (DX- MWT-MSL (Severe OSA); Comparison of means by visit and Obstructive Sleep Apnea (OSA) severity; P\<0.05 indicates statistical significance for P values.)Chop-lump test was selected due to a high frequency of scores at the twenty-minute ceiling.
  • Active CPAP vs Sham CPAP · Chop-lump Wilcoxon · p = 0.0052 (2M- MWT-MSL; Comparison of means by visit only; P\<0.05 indicates statistical significance for P values.)Chop-lump test was selected due to a high frequency of scores at the twenty-minute ceiling.
  • Active CPAP vs Sham CPAP · Chop-lump Wilcoxon · p = 0.2476 (2M- MWT-MSL (Mild OSA); Comparison of means by visit and Obstructive Sleep Apnea (OSA) severity; P\<0.05 indicates statistical significance for P values.)Chop-lump test was selected due to a high frequency of scores at the twenty-minute ceiling.
  • Active CPAP vs Sham CPAP · Chop-lump Wilcoxon · p = 0.7520 (2M- MWT-MSL (Moderate OSA); Comparison of means by visit and Obstructive Sleep Apnea (OSA) severity; P\<0.05 indicates statistical significance for P values.)Chop-lump test was selected due to a high frequency of scores at the twenty-minute ceiling.
  • Active CPAP vs Sham CPAP · Chop-lump Wilcoxon · p = 0.0002 (2M- MWT-MSL (Severe OSA); Comparison of means by visit and Obstructive Sleep Apnea (OSA) severity; P\<0.05 indicates statistical significance for P values.)Chop-lump test was selected due to a high frequency of scores at the twenty-minute ceiling.
  • Active CPAP vs Sham CPAP · Chop-lump Wilcoxon · p = 0.0022 (6M- MWT-MSL; Comparison of means by visit only; P\<0.05 indicates statistical significance for P values.)Chop-lump test was selected due to a high frequency of scores at the twenty-minute ceiling.
  • Active CPAP vs Sham CPAP · Chop-lump Wilcoxon · p = 0.7630 (6M- MWT-MSL (Mild OSA); Comparison of means by visit and Obstructive Sleep Apnea (OSA) severity; P\<0.05 indicates statistical significance for P values.)Chop-lump test was selected due to a high frequency of scores at the twenty-minute ceiling.
  • Active CPAP vs Sham CPAP · Chop-lump Wilcoxon · p = 0.5170 (6M- MWT-MSL (Moderate OSA); Comparison of means by visit and Obstructive Sleep Apnea (OSA) severity; P\<0.05 indicates statistical significance for P values.)Chop-lump test was selected due to a high frequency of scores at the twenty-minute ceiling.
  • Active CPAP vs Sham CPAP · Chop-lump Wilcoxon · p = 0.0002 (6M- MWT-MSL (Severe OSA); Comparison of means by visit and Obstructive Sleep Apnea (OSA) severity; P\<0.05 indicates statistical significance for P values.)Chop-lump test was selected due to a high frequency of scores at the twenty-minute ceiling.
SecondarySubjective Sleepiness/Alertness: Epworth Sleepiness Scale- Total Score (ESS-TS)

Subjective sleepiness/alertness was measured using the Epworth Sleepiness Scale (ESS); the outcome variable was ESS Total Score (ESS-TS). The ESS is a validated questionnaire (8 questions) that ask the chances of dozing off in specific situations. Summing the scores produces a scaled total score between 0 and 24, with higher numbers indicating more subjective sleepiness. The ESS was administered the evening before the polysomnogram (PSG), or overnight sleep study. Data reported here include questionnaires collected at the DX, 2M, and 6M visits.

Time frame:
Measured at diagnostic visit (baseline) and 2 months and 6 months post intervention
Reported as:
Mean · scores on a scale
Subjective Sleepiness/Alertness: Epworth Sleepiness Scale- Total Score (ESS-TS)
scores on a scaleActive CPAPSham CPAP
DX ESS-TS10.07 ± 4.2610.09 ± 4.39
DX ESS-TS Mild OSA10.10 ± 4.559.73 ± 4.43
DX ESS-TS Moderate OSA9.57 ± 4.139.75 ± 4.56
DX ESS-TS Severe OSA10.35 ± 4.2410.37 ± 4.28
2M ESS-TS7.86 ± 4.208.89 ± 4.31
2M ESS-TS Mild OSA8.59 ± 4.317.90 ± 4.01
2M ESS-TS Moderate OSA7.25 ± 3.898.39 ± 4.29
2M ESS-TS Severe OSA8.00 ± 4.319.34 ± 4.34
6M ESS-TS7.39 ± 4.218.41 ± 4.18
6M ESS-TS Mild OSA8.37 ± 4.647.64 ± 3.98
6M ESS-TS Moderate OSA7.07 ± 3.878.43 ± 4.55
6M ESS-TS Severe OSA7.31 ± 4.258.56 ± 4.02
Statistical analysis
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.9291 (DX- ESS-TS; Comparison of means by visit only; P\<0.05 indicates statistical significance for P values.)Regression analyses for the ESS used Generalized Linear Models (GLM) for an over-dispersed binomial distribution.
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.6152 (DX- ESS-TS (Mild OSA); Comparison of means by visit and Obstructive Sleep Apnea (OSA) severity; P\<0.05 indicates statistical significance for P values.)Regression analyses for the ESS used Generalized Linear Models (GLM) for an over-dispersed binomial distribution.
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.7040 (DX- ESS-TS (Moderate OSA); Comparison of means by visit and Obstructive Sleep Apnea (OSA) severity; P\<0.05 indicates statistical significance for P values.)Regression analyses for the ESS used Generalized Linear Models (GLM) for an over-dispersed binomial distribution.
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.9537 (DX- ESS-TS (Severe OSA); Comparison of means by visit and Obstructive Sleep Apnea (OSA) severity; P\<0.05 indicates statistical significance for P values.)Regression analyses for the ESS used Generalized Linear Models (GLM) for an over-dispersed binomial distribution.
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.0004 (2M- ESS-TS; Comparison of means by visit only; P\<0.05 indicates statistical significance for P values.)Regression analyses for the ESS used Generalized Linear Models (GLM) for an over-dispersed binomial distribution.
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.3886 (2M- ESS-TS (Mild OSA); Comparison of means by visit and Obstructive Sleep Apnea (OSA) severity; P\<0.05 indicates statistical significance for P values.)Regression analyses for the ESS used Generalized Linear Models (GLM) for an over-dispersed binomial distribution.
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.0236 (2M- ESS-TS (Moderate OSA); Comparison of means by visit and Obstructive Sleep Apnea (OSA) severity; P\<0.05 indicates statistical significance for P values.)Regression analyses for the ESS used Generalized Linear Models (GLM) for an over-dispersed binomial distribution.
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.0005 (2M- ESS-TS (Severe OSA); Comparison of means by visit and Obstructive Sleep Apnea (OSA) severity; P\<0.05 indicates statistical significance for P values.)Regression analyses for the ESS used Generalized Linear Models (GLM) for an over-dispersed binomial distribution.
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.0005 (6M- ESS-TS; Comparison of means by visit only; P\<0.05 indicates statistical significance for P values.)Regression analyses for the ESS used Generalized Linear Models (GLM) for an over-dispersed binomial distribution.
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.3796 (6M- ESS-TS (Mild OSA); Comparison of means by visit and Obstructive Sleep Apnea (OSA) severity; P\<0.05 indicates statistical significance for P values.)Regression analyses for the ESS used Generalized Linear Models (GLM) for an over-dispersed binomial distribution.
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.0106 (6M- ESS-TS (Moderate OSA); Comparison of means by visit and Obstructive Sleep Apnea (OSA) severity; P\<0.05 indicates statistical significance for P values.)Regression analyses for the ESS used Generalized Linear Models (GLM) for an over-dispersed binomial distribution.
  • Active CPAP vs Sham CPAP · Regression, Linear · p = 0.0010 (6M- ESS-TS (Severe OSA); Comparison of means by visit and Obstructive Sleep Apnea (OSA) severity; P\<0.05 indicates statistical significance for P values.)Regression analyses for the ESS used Generalized Linear Models (GLM) for an over-dispersed binomial distribution.
SecondaryMood
Time frame:
Measured at diagnostic visit (baseline) and 2 months and 6 months post intervention

No measurements were reported for this outcome.

SecondaryQuality of Life: Calgary Sleep Apnea Quality of Life Index- Total Score (SAQLI-TS)

Quality of life was measured using the Calgary Sleep Apnea Quality of Life Index (SAQLI), which is an interview-administered instrument with high internal consistency and reliability. The SAQLI was designed to assess components identified as important to patients including daily functioning, social interactions, emotional functioning, symptoms experienced, and treatment-related symptoms. Items are scored on a seven-point scale, averaged (taking into account treatment-related symptoms), to yield a composite score between 1 and 7, where higher scores represent better quality of life.

Time frame:
diagnostic visit (baseline)
Reported as:
Mean · Units on a scale
Quality of Life: Calgary Sleep Apnea Quality of Life Index- Total Score (SAQLI-TS)
Units on a scaleActive CPAPSham CPAP
Quality of Life: Calgary Sleep Apnea Quality of Life Index- Total Score (SAQLI-TS)4.7 ± 0.84.7 ± 0.8
Other pre-specifiedFunctional Magnetic Resonance Imaging (fMRI)
Time frame:
Measured at diagnostic visit (baseline) and 6 months post intervention

No measurements were reported for this outcome.

Adverse events

Collected over Adverse event data were collected from participant enrollment though the end of study visit (6 months). The APPLES Data and Safety Monitoring Board (DSMB) indicated events should be reported by body systems/event categories; data are reported this way.. Non-serious events are listed at a 0% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
Active CPAP—32/556 (5.8%)390/556 (70.1%)
Sham CPAP—31/542 (5.7%)373/542 (68.8%)
Most frequent serious events
Showing 10 of 14
Most frequent serious events
EventActive CPAPSham CPAP
MusculoskeletalMusculoskeletal and connective tissue disorders13/5565/542
CardiovascularCardiac disorders4/5566/542
GI / DigestiveGastrointestinal disorders6/5565/542
GenitourinaryRenal and urinary disorders0/5564/542
GeneralGeneral disorders2/5563/542
Near-miss MVAGeneral disorders0/5563/542
Other accidentGeneral disorders1/5563/542
RespiratoryRespiratory, thoracic and mediastinal disorders1/5563/542
NeurologicalNervous system disorders3/5560/542
DeathGeneral disorders2/5562/542
Most frequent other events
Showing 10 of 16
Most frequent other events
EventActive CPAPSham CPAP
HEENTGeneral disorders207/556154/542
RespiratoryRespiratory, thoracic and mediastinal disorders135/556153/542
DermatologicalSkin and subcutaneous tissue disorders101/55661/542
PsychiatricPsychiatric disorders42/55659/542
GeneralGeneral disorders52/55636/542
MusculoskeletalMusculoskeletal and connective tissue disorders44/55645/542
NeurologicalNervous system disorders33/55632/542
GI / DigestiveGastrointestinal disorders32/55628/542
CardiovascularCardiac disorders27/55623/542
Other AccidentGeneral disorders20/55625/542

Baseline characteristics

Age, Categorical
Age, Categorical(Participants)Active CPAPSham CPAPTotal
<=18 years101
Between 18 and 65 years459464923
>=65 years9678174
Age, Continuous
Age, Continuous(years)Active CPAPSham CPAPTotal
Mean52.2 ± 12.250.8 ± 12.251.5 ± 12.2
Sex: Female, Male
Sex: Female, Male(Participants)Active CPAPSham CPAPTotal
Female193186379
Male363356719
Region of Enrollment
Region of Enrollment(participants)Active CPAPSham CPAPTotal
United States5565421098
08

Study locations

5 sites
  • University of Arizona AHSC
    Tucson, Arizona 85724, United States
  • Stanford University School of Medicine
    Palo Alto, California 94305, United States
  • Brigham & Women's Hospital
    Boston, Massachusetts 02459, United States
  • St. Luke's Hospital
    Chesterfield, Missouri 63017, United States
  • St. Mary Medical Center
    Walla Walla, Washington 99362, United States
09

References and documents

Publications

  • Kushida CA, Nichols DA, Quan SF, Goodwin JL, White DP, Gottlieb DJ, Walsh JK, Schweitzer PK, Guilleminault C, Simon RD, Leary EB, Hyde PR, Holmes TH, Bloch DA, Green S, McEvoy LK, Gevins A, Dement WC. The Apnea Positive Pressure Long-term Efficacy Study (APPLES): rationale, design, methods, and procedures. J Clin Sleep Med. 2006 Jul 15;2(3):288-300. PubMed 17561541 ↗
  • Holmes TH, Nichols DA, Thomander D, Kushida CA. A method for estimating normative distributions for study-specific populations of clinical trials. Contemp Clin Trials. 2012 Mar;33(2):445-9. doi: 10.1016/j.cct.2011.11.014. Epub 2011 Nov 25. PubMed 22138103 ↗
  • Gevins A, Smith ME, McEvoy LK, Ilan AB, Chan CS, Jiang A, Sam-Vargas L, Abraham G. A cognitive and neurophysiological test of change from an individual's baseline. Clin Neurophysiol. 2011 Jan;122(1):114-20. doi: 10.1016/j.clinph.2010.06.010. Epub 2010 Jul 8. PubMed 20619727 ↗
  • Quan SF, Chan CS, Dement WC, Gevins A, Goodwin JL, Gottlieb DJ, Green S, Guilleminault C, Hirshkowitz M, Hyde PR, Kay GG, Leary EB, Nichols DA, Schweitzer PK, Simon RD, Walsh JK, Kushida CA. The association between obstructive sleep apnea and neurocognitive performance--the Apnea Positive Pressure Long-term Efficacy Study (APPLES). Sleep. 2011 Mar 1;34(3):303-314B. doi: 10.1093/sleep/34.3.303. PubMed 21358847 ↗
  • Kushida CA, Nichols DA, Holmes TH, Quan SF, Walsh JK, Gottlieb DJ, Simon RD Jr, Guilleminault C, White DP, Goodwin JL, Schweitzer PK, Leary EB, Hyde PR, Hirshkowitz M, Green S, McEvoy LK, Chan C, Gevins A, Kay GG, Bloch DA, Crabtree T, Dement WC. Effects of continuous positive airway pressure on neurocognitive function in obstructive sleep apnea patients: The Apnea Positive Pressure Long-term Efficacy Study (APPLES). Sleep. 2012 Dec 1;35(12):1593-602. doi: 10.5665/sleep.2226. Erratum In: Sleep. 2016 Jul 1;39(7):1483. doi: 10.5665/sleep.5988. PubMed 23204602 ↗
  • Vasquez MM, Goodwin JL, Drescher AA, Smith TW, Quan SF. Associations of dietary intake and physical activity with sleep disordered breathing in the Apnea Positive Pressure Long-Term Efficacy Study (APPLES). J Clin Sleep Med. 2008 Oct 15;4(5):411-8. PubMed 18853696 ↗
  • Quan SF, Budhiraja R, Clarke DP, Goodwin JL, Gottlieb DJ, Nichols DA, Simon RD, Smith TW, Walsh JK, Kushida CA. Impact of treatment with continuous positive airway pressure (CPAP) on weight in obstructive sleep apnea. J Clin Sleep Med. 2013 Oct 15;9(10):989-93. doi: 10.5664/jcsm.3064. PubMed 24127141 ↗
  • Batool-Anwar S, Goodwin JL, Drescher AA, Baldwin CM, Simon RD, Smith TW, Quan SF. Impact of CPAP on activity patterns and diet in patients with obstructive sleep apnea (OSA). J Clin Sleep Med. 2014 May 15;10(5):465-72. doi: 10.5664/jcsm.3686. PubMed 24910546 ↗
  • Quan SF, Budhiraja R, Batool-Anwar S, Gottlieb DJ, Eichling P, Patel S, Shen W, Walsh JK, Kushida CA. Lack of Impact of Mild Obstructive Sleep Apnea on Sleepiness, Mood and Quality of Life. Southwest J Pulm Crit Care. 2014;9(1):44-56. doi: 10.13175/swjpcc082-14. PubMed 25232509 ↗
  • Quan SF, Budhiraja R, Clarke DP, Goodwin JL, Gottlieb DJ, Nichols DA, Simon RD, Smith TW, Walsh JK, Kushida CA, Phillips B. You still need more than CPAP for OSA patients to lose weight. J Clin Sleep Med. 2014 Mar 15;10(3):349. doi: 10.5664/jcsm.3552. No abstract available. PubMed 24634638 ↗
  • Prilipko O, Huynh N, Thomason ME, Kushida CA, Guilleminault C. An fMRI study of cerebrovascular reactivity and perfusion in obstructive sleep apnea patients before and after CPAP treatment. Sleep Med. 2014 Aug;15(8):892-8. doi: 10.1016/j.sleep.2014.04.004. Epub 2014 May 4. PubMed 24916094 ↗
  • Huynh NT, Prilipko O, Kushida CA, Guilleminault C. Volumetric Brain Morphometry Changes in Patients with Obstructive Sleep Apnea Syndrome: Effects of CPAP Treatment and Literature Review. Front Neurol. 2014 Apr 29;5:58. doi: 10.3389/fneur.2014.00058. eCollection 2014. PubMed 24808886 ↗
  • Prilipko O, Huynh N, Schwartz S, Tantrakul V, Kushida C, Paiva T, Guilleminault C. The effects of CPAP treatment on task positive and default mode networks in obstructive sleep apnea patients: an fMRI study. PLoS One. 2012;7(12):e47433. doi: 10.1371/journal.pone.0047433. Epub 2012 Dec 5. PubMed 23227139 ↗
  • Prilipko O, Huynh N, Schwartz S, Tantrakul V, Kim JH, Peralta AR, Kushida C, Paiva T, Guilleminault C. Task positive and default mode networks during a parametric working memory task in obstructive sleep apnea patients and healthy controls. Sleep. 2011 Mar 1;34(3):293-301A. doi: 10.1093/sleep/34.3.293. PubMed 21358846 ↗
  • Budhiraja R, Kushida CA, Nichols DA, Walsh JK, Simon RD, Gottlieb DJ, Quan SF. Impact of Randomization, Clinic Visits, and Medical and Psychiatric Cormorbidities on Continuous Positive Airway Pressure Adherence in Obstructive Sleep Apnea. J Clin Sleep Med. 2016 Mar;12(3):333-41. doi: 10.5664/jcsm.5578. PubMed 26518698 ↗
  • Batool-Anwar S, Goodwin JL, Kushida CA, Walsh JA, Simon RD, Nichols DA, Quan SF. Impact of continuous positive airway pressure (CPAP) on quality of life in patients with obstructive sleep apnea (OSA). J Sleep Res. 2016 Dec;25(6):731-738. doi: 10.1111/jsr.12430. Epub 2016 May 30. PubMed 27242272 ↗
  • Batool-Anwar S, Omobomi O, Quan SF. The effect of CPAP on HRQOL as measured by the Quality of Well-Being Self Administered Questionaire (QWB-SA). Southwest J Pulm Crit Care. 2020;20(1):29-40. doi: 10.13175/swjpcc070-19. PubMed 32190413 ↗
  • Holmes TH, Kushida CA. Adherence to continuous positive airway pressure improves attention/psychomotor function and sleepiness: a bias-reduction method with further assessment of APPLES. Sleep Med. 2017 Sep;37:130-134. doi: 10.1016/j.sleep.2017.06.022. Epub 2017 Jul 14. Erratum In: Sleep Med. 2019 May;57:162. doi: 10.1016/j.sleep.2019.02.010. PubMed 28899524 ↗

Individual participant data

Plan to share: Yes — Only in de-identified format to researchers

10

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Nov 28, 2018, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
11

Registry details

Key details

Study ID
NCT00051363
Lead sponsor
Stanford University
Collaborators
National Heart, Lung, and Blood Institute (NHLBI)
Responsible party
Clete A. Kushida (Principal Investigator, Stanford University) — Principal investigator
First posted
Jan 13, 2003
Start date
Sep 2002
Primary completion
Aug 2008
Completion
Sep 2008
Results posted
Nov 30, 2016
Last update
Nov 28, 2018

Study contacts

William C. Dement, MD, PhD
study chair · Stanford University
Clete A. Kushida, MD, PhD
principal investigator · Stanford University

Oversight

Data monitoring committee
Yes
View the source record on ClinicalTrials.gov ↗

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