40 Hz Visual Stimulation as an Intervention in Schizophrenia
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18+
SponsorTechnical University of Munich
About this trial
In schizophrenia, an abnormal reduction in neuronal gamma oscillations (30-100 Hz) is associated with negative symptoms such as cognitive dysfunction. The literature suggests that rescuing gamma oscillations through non-invasive brain stimulation may be an accessible and safe add-on strategy to mitigate negative symptoms. Here, a stimulation protocol based on gamma visual stimulation will be tested. This pilot study will follow an uncontrolled clinical trial design: A minimum of ten patients diagnosed with schizophrenia or a schizoaffective disorder and predominant negative symptoms will be recruited at Klinikum rechts der Isar. They will undergo a multisession stimulation protocol, consisting of one hour of 40 Hz visual stimulation per day over five consecutive days, during which they will be encouraged to fall asleep. An equal number of patients will be recruited for a treatment-as-usual group without intervention. Pre- and post-assessments will include EEG, a cognitive test battery (THINC-IT), a mood scale (PANAS), and a schizophrenia symptom scale (PANSS). This study's results will inform on the feasibility of gamma visual stimulation as a potential add-on intervention in schizophrenia.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Medical diagnosis of schizophrenia (F20) or schizoaffective disorder (F25)
Disqualifiers
Age < 18 years
Any history of seizures
Acute suicidality assessed with the Columbia-Suicide Severity Rating Scale (C-SSRS; Brent et al., 2008)
Any other relevant axis 1 disorder
Trial design
Design model
Parallel
Treatments tested in this trial
Visual stimulation
Device40 Hz visual stimulation will be delivered at the same time of day over 5 consecutive days. Participants will lay down while wearing the customized sleep mask with inbuilt red LEDs flickering at 40 Hz linked to a microcontroller. Participants will be asked to keep their eyes closed and encouraged to fall asleep for the full stimulation duration of 60 minutes.
Treatment groups
20 Participants
are divided into 2 treatment groupsGroup A: Visual stimulationExperimental treatment 1 intervention
Group B: TAU controlNo intervention 0 interventions
Trial outcomes
Primary outcomes
1
Visually evoked neuronal 40 Hz activity represented in the frequency domain
Steady-State Visually Evoked Potentials (SSVEP) at 40 Hz as an electrophysiological measure of neuronal responses to 40 Hz visual stimulation, represented in the frequency domain. A higher signal-to-noise ratio value at 40 Hz (unit-free), ranging from zero to infinite, represents a larger neuronal response.
Time frame
Sessions 1 and 5 (first and last of the five stimulation days)2
Visually evoked neuronal 40 Hz activity represented in the time domain
Steady-State Visually Evoked Potentials (SSVEP) at 40 Hz as an electrophysiological measure of neuronal responses to 40 Hz visual stimulation, represented in the time domain. A larger peak-to-peak amplitude of the segment average in microvolts, ranging from zero to infinite, represents a larger neuronal response.
Time frame
Sessions 1 and 5 (first and last of the five stimulation days)Secondary outcomes
1
Safety as indicated by the total number and severity of adverse events
Verbally inquired reports of adverse events (question: "Have you experienced any undesired effects during or after the stimulation?"). Severity rated as mild/moderate/severe; how likely it was related to the stimulation rated as unlikely/likely/certain. The intervention will be judged as "safe" if no adverse events are reported as severe and likely or certain to be related to the intervention.
Time frame
Sessions 1, 2, 3, 4, 5 (from the first throughout the last of the five stimulation days)2
Positive and negative mood assessed by the PANAS scale
Mood will be measured with the Positive And Negative Affect Schedule (PANAS; Watson et al., 1988). The negative and positive affect scores, each ranging from 10 to 50, will be subjected to statistical analyses separately. Mood improvements are quantified as a score increase in the positive scale from session 0 to session 5 and a score decrease in the negative scale from session 0 to session 5.
Time frame
Session 0 (five to one day(s) before the first stimulation) and session 5 (immediately after the last stimulation)3
Schizophrenia negative symptoms measured with the PANSS negative scale
The Positive and Negative Syndrome Scale (PANSS; Kay et al., 1987) will be administered by a trained physician to quantify schizophrenia-related psychiatric symptoms. The negative syndrome score, ranging from 7 to 49, will be used for statistical analyses. Improvement is quantified as a score decrease from before the stimulation to after the stimulation.
Time frame
Five to one day(s) before the first stimulation and zero to three day(s) after the last stimulation4
Cognitive improvement assessed with the THINC-IT test battery
Cognition will be assessed using the THINC-integrated tool (THINC-IT; Harrison et al., 2018). It has five components: Spotter (Choice Reaction Time), Symbol Check (1-back test), Trails (Trails Making Test B), Codebreaker (Digit Symbol Substitution Test), and a self-reported cognitive function questionnaire (5-item Perceived Deficit Questionnaire). For the self-reported questionnaire, higher total scores (range 5-25) mean a better outcome. For the other four subtests, lower reaction times (in milliseconds, range 0 to infinite), lower error rates (range 0 to total number of items per task), and fewer missing responses (range 0 to total number of items per task) mean a better outcome. Cognitive performance will be reported descriptively as the participant-level profile across subtests, measures, and sessions.
Time frame
Session 0 (five to one day(s) before the first stimulation) and session 5 (immediately after the last stimulation)Sponsors and contacts
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Source ClinicalTrials.gov