An observational study in Dysarthria and Acquired Brain Injury, sponsored by University of Salamanca. Recruiting at 1 site in Spain. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-02-27.
Sponsored by University of Salamanca · Observational
The goal of this observational study is to describe speech and breathing patterns in adults after acquired brain injury (ABI) and understand how these patterns relate to the presence, severity, and type of dysarthria. The main questions it aims to answer are:
Participants will:
About 97 to 101 participants will take part. The results will help speech therapists better detect, evaluate, and treat dysarthria in adults after brain injury.
This cross-sectional observational study aims to characterise acoustic, respiratory, and clinical speech parameters in adults with acquired brain injury (ABI) and to examine their associations with the presence and severity of dysarthria. The study is limited to baseline assessment and does not include therapeutic intervention or longitudinal follow-up.
Participants complete a standardised evaluation protocol conducted in a controlled clinical setting. All assessments are performed within a short and predefined evaluation period to minimise fatigue and contextual variability. The protocol comprises three assessment sessions: (1) acoustic and aerodynamic speech evaluation based on sustained phonation vowels /a/, /i/, /u/, /o/ and connected speech tasks; (2) objective assessment of respiratory function using spirometry; and (3) clinical assessment of dysarthria using the Frenchay Dysarthria Assessment-2 (FDA-2).
Speech recordings are obtained under standardised conditions to ensure consistency across participants and reliable extraction of acoustic measures. Respiratory assessments are performed according to established international guidelines to ensure validity and reproducibility. Data from acoustic, respiratory, and clinical assessments are analysed jointly to explore associations between phonorespiratory function and dysarthria severity in adults with ABI.
The study population will include adult participants aged 18 years or older with a diagnosis of acquired brain injury (ABI), including stroke, traumatic brain injury, or brain tumor. Participants will be recruited from hospitals, clinics, and patient associations in Salamanca, Spain. Both individuals with and without dysarthria secondary to ABI will be included. All participants must have preserved cognitive function (Mini-Mental State Examination score ≥ 24) and be able to provide written informed consent or have a legally authorized representative provide consent if necessary.
Participants with chronic respiratory diseases, significant hearing impairments, additional neurological or neurodegenerative disorders, pre-existing voice disorders, severe aphasia, or persistent pharyngeal symptoms will be excluded.
The sample size is estimated to be between 97 and 150 participants, considering a dysarthria prevalence of 60% in the ABI population, a 95% confidence level, and a margin of err
Diagnosed with acquired brain injury (ABI), including:
Exclusion Criteria:
Dysarthria severity assessed by the Frenchay Dysarthria Assessment-2 (FDA-2)
Severity of dysarthria assessed using the Frenchay Dysarthria Assessment-2 (FDA-2), reported as a total score reflecting overall speech motor impairment. Unit of Measure: FDA-2 total score (ordinal scale)
Time frame: Baseline
Vowel Space Area (VSA)
Vowel Space Area calculated from the first and second formant frequencies (F1-F2) of the corner vowels (/i/, /a/, /u/), expressed in kHz², reflecting articulatory working space and articulatory precision.
Time frame: Baseline
Formant Centralization Ratio (FCR)
Formant Centralization Ratio derived from mean formant frequencies of the vowels (/a, e, i, o, u/), expressed as a dimensionless ratio, reflecting vowel centralization and articulatory impairment.
Time frame: Baseline
Median Fundamental Frequency (F₀)
Median fundamental frequency (F0) of sustained /a/ vowel phonation, expressed in Hertz (Hz).
Time frame: Baseline
Jitter
Short-term frequency perturbation of sustained /a/ vowel phonation, expressed as a percentage (%).
Time frame: Baseline
Shimmer
Short-term amplitude perturbation of sustained /a/ vowel phonation, expressed as a percentage (%).
Time frame: Baseline
Harmonics-to-Noise Ratio (HNR)
Ratio between noise and harmonic components of the sustained /a/ vowel phonation, expressed in decibels (dB).
Time frame: Baseline
Maximum Phonation Time (MPT)
Maximum duration of sustained vowel phonation (/a/) measured during a standardized task, expressed in seconds (s).
Time frame: Baseline
Maximum Emission Time (MET)
Maximum duration of sustained fricative emission measured during a standardized task, expressed in seconds (s).
Time frame: Baseline
s/z Ratio
Ratio between maximum sustained durations of voiceless (/s/) and voiced (/z/) fricative emissions, expressed as a dimensionless ratio.
Time frame: Baseline
Vital Capacity (VC)
Vital capacity measured by standard spirometry, defined as the maximum volume of air exhaled following a maximal inhalation, expressed in litres (L).
Time frame: Baseline
Forced Vital Capacity (FVC)
Forced vital capacity measured by standard spirometry during a forced expiratory manoeuvre, expressed in litres (L).
Time frame: Baseline
Forced Expiratory Volume in One Second (FEV₁)
Forced expiratory volume in the first second measured by standard spirometry, expressed in litres (L).
Time frame: Baseline
Maximum Voluntary Ventilation (MVV)
Maximum voluntary ventilation measured by standard spirometry during rapid and deep breathing, expressed in litres per minute (L/min).
Time frame: Baseline
FEV₁/FVC Ratio
Ratio between forced expiratory volume in one second and forced vital capacity, expressed as a percentage (%).
Time frame: Baseline
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University of Salamanca