The purpose of this clinical trial is to measure the safety and effectiveness of a non-invasive brain stimulation device called Transcranial Alternating Current Stimulation (tACS) in participants with bipolar disorder (BD). Participants will be asked to come in for 3 sessions. If participants qualify at the screening visit (session 1) then enrolled participants will complete sessions 2 and 3 as well as have a 30-day follow-up phone call.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
18
Participants will wear an EEG cap on the head attached with EEG-recording and tACS electrodes. tACS will be delivered by passing a small electrical current via the tACS electrodes to the scalp to stimulate brain activity during a computerized behavioral task. The effect of active stimulation on EEG will be measured via EEG-recording electrodes during short rests (between stimulation blocks). The stimulation session will last for approximately 60 minutes. After treatment, participants will be asked about the experience and if there are any side effects.
Participants will wear an EEG cap on the head attached with EEG-recording and tACS electrodes. Sham tACS will be delivered by passing a transient (approximately 12 seconds ) small electrical current via the tACS electrodes during a computerized behavioral task. The effect of sham stimulation on EEG will be measured via EEG-recording electrodes during short rests (between stimulation blocks). The sham stimulation session will last for approximately 60 minutes. After treatment, participants will be asked about the experience and if there are any side effects.
University of Michigan
Ann Arbor, Michigan, United States
Severity of Side Effects Reported at End of Stimulation Session as Reported by the Participant on the Stimulation Side Effects Questionnaire.
The score was calculated by summing the severity score of items that were rated by the participant as related to stimulation on the Stimulation Side Effects Questionnaire. There was a total of 14 symptoms listed on the questionnaire. Participants rated each item rated on a scale of 0-4, with 0 meaning no relation and 4 meaning definitely related. The total possible range of the questionnaire was 0-56.
Time frame: Up to 3 weeks
Participants Who Withdrew During or After the Stimulation Session
Results reflect the number of participants who withdrew from the trial during or after a stimulation session with either the tACS or the sham stimulation treatment.
Time frame: Up to 3 weeks
Accuracy Signal Detection Theory Metric Sensitivity (d') Derived From the Behavioral Responses to Go and NoGo Trials on the Cognitive Control Task.
The Go/NoGo task was a cognitive task, where participants were shown "go" stimuli (i.e., go trials) and "no-go" stimuli and responded by pressing a button when seeing "go" stimuli and not responding when seeing the "no-go" stimuli. Accuracy was measured by calculating D' (D prime), which provided a measure of perceptual sensitivity to the differing stimuli. Larger values of D' indicated greater discernability (i.e., accuracy) between the Go and NoGo trials. D-prime, also called the sensitivity index represents how well someone can detect a signal amidst background noise. At its core, D-prime is the standardized difference between the means of the Signal Present and Signal Absent distributions, which can be calculated by taking the difference between the Z-score of the False Alarm Rate and the Z-scores of the Hit Rate. A D-prime of 0 means no sensitivity. Negative D-prime values are rare and may indicate errors or reversed interpretations of hits and false alarms.
Time frame: Up to 3 weeks
Accuracy Signal Detection Theory Metric Response Bias Derived From the Behavioral Responses to Go and NoGo Trials on the Cognitive Control Task.
The Go/NoGo task was a cognitive task, where participants were shown "go" stimuli (i.e., go trials) and "no-go" stimuli and responded by pressing a button when seeing "go" stimuli and not responding when seeing the "no-go" stimuli. Response bias was measured using beta, such that more negative beta values indicated a stronger tendency to respond to all stimuli, regardless of "go" or "no-go" status. Response bias is indexed by taking the average between the Z-score of the False Alarm Rate and the Z-scores of the Hit Rate. A higher response bias indicates that the participant is more likely to respond "signal absent" (favors avoiding false alarms but increases misses). A response bias of 0 means the individual equally weighs the costs of misses and false alarms. A more negative response bias indicated that the participant is more likely to respond "signal present" (favors hits but increases false alarms).
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Time frame: Up to 3 weeks
Reaction Time (in Milliseconds) of Go Trials on the Cognitive Control Task
Participants' reaction time to responding to the "Go" signal during the Go/NoGo task was measured.
Time frame: Up to 3 weeks
Theta-gamma Phase Amplitude Coupling (PAC) (Kullback-Leibler Modulation Index) During the Rest EEG Blocks Interleaved Between Stimulation Blocks.
Theta-gamma phase-amplitude coupling (PAC) is a neural phenomenon observed in the brain, where the phase of slower theta oscillations modulates the amplitude of faster gamma oscillations. This type of coupling is thought to play a critical role in various cognitive control. For the trial, higher PAC values indicated higher levels of coupling or connection between the two frequencies (i.e., increased cognitive control).
Time frame: Up to 3 weeks