An interventional study of Bright light treatment lamp and Sham negative ion generator in Bright Light Treatment, Emotion and Facial Expression Recognition, sponsored by University of Oxford. Completed at 1 site in United Kingdom. Open to participants aged 18 Years to 65 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2018-10-03.
Sponsored by University of Oxford · Not applicable, Interventional, and Basic science
This study aims to investigate the effects of a single session of bright light treatment (BLT) on emotional information processing in healthy volunteers. We hypothesised that BLT can acutely push the processing of emotional information towards a prioritisation of positive (relative to negative) input. To test this hypothesis, healthy volunteers were randomly allocated to receive either bright light treatment or sham-placebo treatment and study participants as well as investigators were blind as to which treatment was used. After treatment, all participants underwent testing with the Oxford Emotional Test Battery, an established set of psychological tasks that allow to assess how emotional information is processed.
Background:
Bright light treatment (BLT) is an efficacious treatment for depressive disorders but the causal mechanisms by which it exerts its clinical effects are largely unknown. According to the cognitive neuropsychological model of antidepressant treatment action, one way by which antidepressant treatments lead to clinical effects is by acutely inducing a relatively increased preferential processing of positive (as compared to negative) emotional stimuli. Whether BLT has the potential to induce such positive biases is not known to date.
Aim of study:
To investigate the influence of single-dose BLT on emotion-related information processing in healthy volunteers.
Methods:
Using a double-blind, parallel-group design, fifty healthy volunteers (male and female) were randomly allocated to a single session (60 minutes) of treatment with either bright light (10 000 lux) or a credible placebo-sham condition (deactivated negative ion generator). After treatment, all participants underwent testing with the Oxford Emotional Test Battery, an established battery of behavioural tasks that allow to assess emotional information processing in multiple cognitive domains. This battery consists of a facial expression recognition task, an emotional categorization task, an emotional dot probe task, an emotional recall task and an emotional recognition task. Before and after treatment, subjective state was assessed using different questionnaires.
Hypotheses:
Our working hypothesis, in line with the cognitive neuropsychological model of antidepressant treatment action, is that one-time BLT can induce biases towards positive stimuli in multiple cognitive domains and this bias will be present even in the absence of observable changes in subjective state.
Implications of the study:
This study will show whether a single dose of BLT can influence emotion-related information processing in a similar way as previously observed for antidepressant drugs. If this is the case, then the clinical effects of BLT could be explained through its acute effects on emotional processing. On a broader level, the results of this study will also add to our understanding of any potential effects that acute exposure to bright light (e.g. sunlight) could have on the healthy human mind.
University of Oxford is the lead sponsor of 794 studies on the registry; 117 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Entry criteria:
Exclusion criteria:
Single-dose bright light treatment (1 hour, 10 000 lux)
Device: Bright light treatment lamp
Deactivated negative ion generator in conjunction with a plausible cover story
Device: Sham negative ion generator
Exposure to bright white light (1 hour, 10 000 lux)
Placebo treatment with deactivated negative ion generator (1 hour, audible hum, no ions emitted)
Performance in a facial expression recognition task
Participants are presented with individual pictures of facial expressions of emotions. Each presented face displays one of six basic emotions (anger, disgust, fear, happiness, sadness, or surprise). Each emotional expression is presented at different levels of intensity which have been created by combining shape and texture features of the two extremes "neutral" (0%) and "full prototypical emotion" (100%) to varying degrees. Examples of neutral facial expressions are presented as well. Participants are instructed to correctly classify each facial expression as angry, disgusted, fearful, happy, sad, surprised or neutral both as quickly and as accurately as possible. Responses are made by pushing one out of seven labelled keys on a response box. Hit rates, false alarm rates, and reaction times for correct classifications are measured separately for each emotion.
Time frame: Completed within 2 hours after treatment
Performance in an emotional categorisation task
Participants are presented with positive and negative personality descriptors and are asked to classify the valence of each word. These words describe either extremely agreeable/positive characteristics (e.g. "cheerful", "honest", "optimistic") or extremely disagreeable/negative characteristics (e.g. "domineering", "untidy", "hostile") and are presented individually in the centre of the screen. Participants are instructed to imagine themselves overhearing someone describing them with each of the words and to indicate as quickly and accurately as possible whether they would like or dislike to be described with each of the words. Responses are made by pressing a correspondingly labelled key on a button box. Reaction times for correct classifications are measured separately for positive and negative words.
Time frame: Completed within 2 hours after treatment
Performance in an emotional faces dot probe task
Pictures of positive and negative emotional stimuli (happy and fearful facial expressions) are presented individually together with a matched neutral stimulus (neutral face). On each trial, one stimulus is shown above and the other below a central fixation point. Subsequently, a probe appears behind one of the stimuli and participants have to correctly classify the probe as quickly and as accurately as possible. Stimuli can be masked (i.e. presented very briefly and followed by a jumbled face) or unmasked (i.e. presented for a longer period without a subsequent masking stimulus). Reaction times for correct responses are recorded and vigilance scores are calculated for masked and unmasked positive and negative stimuli by subtracting reaction time data from trials when the probe appeared in the same position as the emotional stimulus (congruent trials) from trials when the probe appeared in the opposite position to the emotional stimulus (incongruent trials).
Time frame: Completed within 2 hours after treatment
Performance in an emotional recall task
Following a delay period after the emotional categorization task (about 15 min), emotional recall memory is assessed. Participants are asked to recall and write down as many words as possible from the emotional categorization task. Numbers of correctly and incorrectly recalled positive and negative words are measured.
Time frame: Completed within 2 hours after treatment
Performance in an emotional recognition task
Following the emotional recall task, emotional recognition memory is assessed by presenting participants with the original personality descriptors plus an equal number of matched distractor words (50% positive, 50% negative). Participants are asked to indicate for each word as accurately and as quickly as possible whether they recognise it from the emotional categorization task. Numbers of correctly and incorrectly recognised items as well as reaction times for correct recognitions are measured separately for positive and negative words.
Time frame: Completed within 2 hours after treatment
Change in subjective mood and energy
Zersen's Befindlichkeits-Skala. Standard questionnaire for subjectively felt mood and energy levels. Total score ranging from 0 to 112. Subscores: Mood (ranging from 0 to 94) and Energy (ranging from 0 to 18). Sum of subscores for mood and energy provide total score. Higher scores represent worse subjective mood and energy.
Time frame: Completed within 2 hours after treatment
Change in positive and negative affect
Positive and Negative Affect Schedule; standard questionnaire for subjectively felt positive and negative affect. Two scores: (1) Positive score: ranging from 10 to 50 (higher score representing greater extent of positive affect). (2) Negative score: ranging from 10 to 50 (higher score representing greater extent of negative affect).
Time frame: Completed within 2 hours after treatment
Change in subjective anxiety
State-Trait Anxiety Inventory; standard questionnaire for subjectively felt anxiety. Two scores: (1) State anxiety: ranging from 20 to 80 (higher scores indicating higher state anxiety levels). (2) Trait Anxiety: ranging from 20 to 80 (higher scores indicating higher trait anxiety levels).
Time frame: Completed within 2 hours after treatment
Change in subjective state
Visual Analogue Scales of different subjective states (anxious, alert, happy, sad, angry, disgusted, afraid); Minimum = 0 mm ("Not at all") , Maximum = 96 mm ("Extremely"); greater scores represent greater extent of felt emotions.
Time frame: Completed within 2 hours after treatment
Plan to share: Undecided
This study is completed, as verified in Sep 2018. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
University of Oxford