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| ID | Type | Description | Link |
|---|---|---|---|
| R01MH101547 | U.S. NIH Grant/Contract | View source |
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| Name | Class |
|---|---|
| National Institute of Mental Health (NIMH) | NIH |
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Investigation of frequency specific transcranial alternating current stimulation on cognitive control signals in frontal cortex
Previous evidence suggests that there are specific frequency bands associated with different aspects of cognitive control. In specific delta (2-4Hz) and beta (15-30Hz) are associated with increased levels of abstraction for learned rules; and theta (5-8Hz) and gamma (30-50Hz) has been associated with increased set-size or number of learned rules. Here we aim to find causal evidence in support of these previous correlational findings by applying cross-frequency transcranial alternating current stimulation (tACS) in the specific frequency bands previously shown to be task-relevant. In a crossover design, we stimulate subjects with either delta-beta or theta-gamma tACS during performance of a hierarchical cognitive control task that manipulates the level of abstraction and set-size of rules that must be learned in order to make the correct button press.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Theta-gamma, Delta-beta, Sham | Experimental | Every participant will receive Theta-gamma tACS, Delta-beta tACS, and Sham tACS on separate sessions during performance of a computerized task. Sequence: Theta-gamma tACS, then Delta-beta tACS, then Sham tACS |
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| Theta-gamma, Sham, Delta-beta | Experimental | Every participant will receive Theta-gamma tACS, Delta-beta tACS, and Sham tACS on separate sessions during performance of a computerized task. Sequence: Theta-gamma tACS, then Sham tACS, then Delta-beta tACS |
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| Delta-beta, Theta-gamma, Sham tACS | Experimental | Every participant will receive Theta-gamma tACS, Delta-beta tACS, and Sham tACS on separate sessions during performance of a computerized task. Sequence: Delta-beta tACS, then Theta-gamma tACS, then Sham tACS |
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| Delta-beta, Sham, Theta-gamma tACS | Experimental | Every participant will receive Theta-gamma tACS, Delta-beta tACS, and Sham tACS on separate sessions during performance of a computerized task. Sequence: Delta-beta tACS, then Sham tACS, then Theta-gamma tACS |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Theta-gamma tACS | Device | NeuroConn technologies, direct current-stimulator plus |
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| Measure | Description | Time Frame |
|---|---|---|
| Reaction Time for Trials With High Abstraction Relative to Low Abstraction | For low abstraction conditions, subjects must memorize a color to button mapping. For high abstraction conditions, subject must make a perceptual judgement on the similarity of two objects based on either texture or shape as cued by a color. The reaction time difference between high and low abstraction conditions was hypothesized to decrease when delta-beta tACS was delivered. As a control for the placebo effect of stimulation, the difference between delta-beta tACS and sham tACS, or placebo, was used for statistical analysis. | through study completion, an average of 3 weeks |
| Reaction Time for Trials With High Set-size Relative to Low Set-size | The reaction time difference between high and low set-size conditions was hypothesized to decrease when theta-gamma tACS is delivered. As a control for the placebo effect of stimulation, the difference between theta-gamma tACS and sham tACS, or placebo, was used for statistical analysis. | through study completion, an average of 3 weeks |
| Delta Phase to Beta Amplitude Coupling Strength | Delta-beta tACS was hypothesized to increase cross frequency coupling strength (higher value) between the targeted frequency bands. Phase amplitude coupling between delta phase and beta amplitude was calculated for the two minute electrical brain recordings after stimulation. A null distribution was calculated by shuffling the beta amplitude time series relative to the delta phase time series and then calculating coupling strength. The outcome measure is the z-transformed value of the genuine phase amplitude coupling relative to the null distribution. | through study completion, an average of 3 weeks |
| Theta Phase to Gamma Amplitude Coupling Strength | Theta-gamma tACS was hypothesized to increase cross frequency coupling strength (higher value) between the targeted frequency bands. Phase amplitude coupling between theta phase and gamma amplitude was calculated for the two minute electrical brain recordings after stimulation. A null distribution was calculated by shuffling the gamma amplitude time series relative to the theta phase time series and then calculating coupling strength. The outcome measure is the z-transformed value of the genuine phase amplitude coupling relative to the null distribution. |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Flavio Frohlich, PhD | University of North Carolina, Chapel Hill | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| University of North Carolina, Chapel Hill | Chapel Hill | North Carolina | 27599 | United States |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 33741402 | Derived | Riddle J, McFerren A, Frohlich F. Causal role of cross-frequency coupling in distinct components of cognitive control. Prog Neurobiol. 2021 Jul;202:102033. doi: 10.1016/j.pneurobio.2021.102033. Epub 2021 Mar 16. |
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| ID | Title | Description |
|---|---|---|
| FG000 | Theta-gamma, Delta-beta, Sham | Every participant will receive Theta-gamma tACS, Delta-beta tACS, and Sham tACS on separate sessions during performance of a computerized task. Sequence: Theta-gamma tACS, then Delta-beta tACS, then Sham tACS Theta-gamma tACS: NeuroConn technologies, direct current-stimulator plus Delta-beta tACS: NeuroConn technologies, direct current-stimulator plus Sham tACS: NeuroConn technologies, direct current-stimulator plus |
| FG001 | Theta-gamma, Sham, Delta-beta | Every participant will receive Theta-gamma tACS, Delta-beta tACS, and Sham tACS on separate sessions during performance of a computerized task. Sequence: Theta-gamma tACS, then Sham tACS, then Delta-beta tACS Theta-gamma tACS: NeuroConn technologies, direct current-stimulator plus Delta-beta tACS: NeuroConn technologies, direct current-stimulator plus Sham tACS: NeuroConn technologies, direct current-stimulator plus |
| FG002 | Delta-beta, Theta-gamma, Sham tACS | Every participant will receive Theta-gamma tACS, Delta-beta tACS, and Sham tACS on separate sessions during performance of a computerized task. Sequence: Delta-beta tACS, then Theta-gamma tACS, then Sham tACS Theta-gamma tACS: NeuroConn technologies, direct current-stimulator plus Delta-beta tACS: NeuroConn technologies, direct current-stimulator plus Sham tACS: NeuroConn technologies, direct current-stimulator plus |
| FG003 | Delta-beta, Sham, Theta-gamma tACS | Every participant will receive Theta-gamma tACS, Delta-beta tACS, and Sham tACS on separate sessions during performance of a computerized task. Sequence: Delta-beta tACS, then Sham tACS, then Theta-gamma tACS Theta-gamma tACS: NeuroConn technologies, direct current-stimulator plus Delta-beta tACS: NeuroConn technologies, direct current-stimulator plus Sham tACS: NeuroConn technologies, direct current-stimulator plus |
| FG004 | Sham, Delta-beta, Theta-gamma tACS | Every participant will receive Theta-gamma tACS, Delta-beta tACS, and Sham tACS on separate sessions during performance of a computerized task. Sequence: Sham tACS, then Delta-beta tACS, then Theta-gamma tACS Theta-gamma tACS: NeuroConn technologies, direct current-stimulator plus Delta-beta tACS: NeuroConn technologies, direct current-stimulator plus Sham tACS: NeuroConn technologies, direct current-stimulator plus |
| FG005 | Sham, Theta-gamma, Delta-beta tACS | Every participant will receive Theta-gamma tACS, Delta-beta tACS, and Sham tACS on separate sessions during performance of a computerized task. Sequence: Sham tACS, then Theta-gamma tACS, then Delta-beta tACS Theta-gamma tACS: NeuroConn technologies, direct current-stimulator plus Delta-beta tACS: NeuroConn technologies, direct current-stimulator plus Sham tACS: NeuroConn technologies, direct current-stimulator plus |
| Title | Milestones | Reasons Not Completed | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Baseline |
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| Pre-Randomization Period (1 Week) |
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| First Intervention |
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| First Washout (1 Week) |
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| Second Intervention |
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| Second Washout (1 Week) |
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| Third Intervention |
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| ID | Title | Description |
|---|---|---|
| BG000 | All Participants | Every participant will receive Theta-gamma tACS, Delta-beta tACS, and Sham tACS on separate sessions during performance of a computerized task. |
| Units | Counts |
|---|---|
| Participants |
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| Title | Description | Population Description | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Denominator Units Selected | Denominators | Classes |
|---|---|---|---|---|---|---|---|---|---|
| Age, Continuous | Mean |
| Type | Title | Description | Population Description | Reporting Status | Anticipated Posting Date | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Time Frame | Units Analyzed | Denominator Units Selected | Arm/Group Information | Denominators | Classes | Analyses | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Primary | Reaction Time for Trials With High Abstraction Relative to Low Abstraction | For low abstraction conditions, subjects must memorize a color to button mapping. For high abstraction conditions, subject must make a perceptual judgement on the similarity of two objects based on either texture or shape as cued by a color. The reaction time difference between high and low abstraction conditions was hypothesized to decrease when delta-beta tACS was delivered. As a control for the placebo effect of stimulation, the difference between delta-beta tACS and sham tACS, or placebo, was used for statistical analysis. | One participant excluded from behavioral analysis because they did not follow task instructions. | Posted | Mean | Standard Deviation | seconds | through study completion, an average of 3 weeks |
|
Adverse events were assessed over an approximate 3-week period using a stimulation side effects questionnaire provided to participants after every presentation of each intervention. Data were not collected beyond the third intervention.
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| ID | Title | Description | Deaths (Affected) | Deaths (At Risk) | Serious Events (Affected) | Serious Events (At Risk) | Other Events (Affected) | Other Events (At Risk) |
|---|---|---|---|---|---|---|---|---|
| EG000 | Theta-gamma tACS | Every participant will receive Theta-gamma tACS during performance of a computerized task using NeuroConn technologies, direct current-stimulator plus |
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| Term | Organ System | Source Vocabulary | Assessment Type | Notes | Statistical Information |
|---|---|---|---|---|---|
| Tingling | Investigations | Systematic Assessment | Mild |
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| Title | Organization | Phone | Extension | |
|---|---|---|---|---|
| Justin Riddle, PhD | University of North Carolina at Chapel Hill | 6617131602 | justin_riddle@med.unc.edu |
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| Type | Includes Protocol | Includes SAP | Includes ICF | Document Label | Document Date | Document Uploaded Date | Document File Name |
|---|---|---|---|---|---|---|---|
| Prot_SAP | Yes | Yes | No | Study Protocol and Statistical Analysis Plan | Jan 9, 2020 | Jan 13, 2020 | Prot_SAP_000.pdf |
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Healthy participants will receive three waveforms of transcranial alternating current stimulation (tACS). Delta-beta, Theta-gamma, and Sham.
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Double-blinded. Neither the investigator nor the participants knows which form of stimulation is received.
| Sham, Delta-beta, Theta-gamma tACS | Experimental | Every participant will receive Theta-gamma tACS, Delta-beta tACS, and Sham tACS on separate sessions during performance of a computerized task. Sequence: Sham tACS, then Delta-beta tACS, then Theta-gamma tACS |
|
| Sham, Theta-gamma, Delta-beta tACS | Experimental | Every participant will receive Theta-gamma tACS, Delta-beta tACS, and Sham tACS on separate sessions during performance of a computerized task. Sequence: Sham tACS, then Theta-gamma tACS, then Delta-beta tACS |
|
| Delta-beta tACS | Device | NeuroConn technologies, direct current-stimulator plus |
|
| Sham tACS | Device | NeuroConn technologies, direct current-stimulator plus |
|
| through study completion, an average of 3 weeks |
| Percent Correct for Trials With High Abstraction Relative to Low Abstraction | For low abstraction conditions, subjects must memorize a color to button mapping. For high abstraction conditions, subject must make a perceptual judgement on the similarity of two objects based on either texture or shape as cued by a color. The accuracy difference between high and low abstraction conditions was hypothesized to decrease when delta-beta tACS was delivered. As a control for the placebo effect of stimulation, the difference between delta-beta tACS and sham tACS, or placebo, was used for statistical analysis. | through study completion, an average of 3 weeks |
| Percent Correct for Trials With High Set-size Relative to Low Set-size | The accuracy difference between high and low set-size conditions was hypothesized to decrease when theta-gamma tACS is delivered. As a control for the placebo effect of stimulation, the difference between theta-gamma tACS and sham tACS, or placebo, was used for statistical analysis. | through study completion, an average of 3 weeks |
| COMPLETED |
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| NOT COMPLETED |
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| COMPLETED |
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| NOT COMPLETED |
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| COMPLETED |
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| NOT COMPLETED |
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| COMPLETED |
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| years |
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| Sex: Female, Male | Count of Participants | Participants |
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| Ethnicity (NIH/OMB) | Count of Participants | Participants |
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| Race (NIH/OMB) | Count of Participants | Participants |
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| Region of Enrollment | Count of Participants | Participants |
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| Baseline Reaction Time Difference for Abstraction | There are four task conditions in a two-by-two design for high and low set-size and high and low abstraction. The reaction time for both high abstraction conditions are averaged and the average reaction time for both low abstraction conditions is subtracted. Thus, a single reaction metric is derived that is the relative change in reaction time as a function of the abstraction of the task. | One participant excluded from behavioral analysis because they did not follow task instructions. Two participants did not complete the full study and thus were excluded from analysis. | Mean | Standard Deviation | seconds |
|
| Baseline Reaction Time Difference for Set-Size | There are four task conditions in a two-by-two design for high and low set-size and high and low abstraction. The reaction time for both high set-size conditions are averaged and the average reaction time for both low set-size conditions is subtracted. Thus, a single reaction metric is derived that is the relative change in reaction time as a function of the set-size of the task. | One participant excluded from behavioral analysis because they did not follow task instructions. Two participants did not complete the full study and thus were excluded from analysis. | Mean | Standard Deviation | seconds |
|
| Baseline Percent Correct Difference for Abstraction | There are four task conditions in a two-by-two design for high and low set-size and high and low abstraction. The percent correct for both high abstraction conditions are averaged and the average percent correct for both low abstraction conditions is subtracted. Thus, a single metric is derived that is the relative change in percent correct as a function of the abstraction of the task. | One participant excluded from behavioral analysis because they did not follow task instructions. Two participants did not complete the full study and thus were excluded from analysis. | Mean | Standard Deviation | percent correct |
|
| Baseline Percent Correct Difference for Set-Size | There are four task conditions in a two-by-two design for high and low set-size and high and low abstraction. The percent correct for both high st-size conditions are averaged and the average percent correct for both low set-size conditions is subtracted. Thus, a single metric is derived that is the relative change in percent correct as a function of the set-size of the task. | One participant excluded from behavioral analysis because they did not follow task instructions. Two participants did not complete the full study and thus were excluded from analysis. | Mean | Standard Deviation | percent correct |
|
| Baseline Delta Phase to Beta Amplitude Coupling | During resting-state EEG, the Hilbert transform is applied at delta (2-3 Hz) and beta (18-22 Hz) frequency band. The phase of delta and the amplitude of beta frequency oscillations are combined into a single hybrid signal. Then, this signal is averaged and the magnitude of the resulting vector is taken as the coupling strength. To account for spurious findings, a null distribution is calculated by randomly shifting the time series of amplitude values. The final coupling measure is z-transformed by subtracting the mean and dividing by the standard deviation of the null distribution. | One participant excluded from behavioral analysis because they did not follow task instructions. Two participants did not complete the full study and thus were excluded from analysis. | Mean | Standard Deviation | Z-score |
|
| Theta Phase to Gamma Amplitude Coupling Strength | During resting-state EEG, the Hilbert transform is applied at theta (4-8 Hz) and gamma (30-50 Hz) frequency band. The phase of theta and the amplitude of gamma frequency oscillations are combined into a single hybrid signal. Then, this signal is averaged and the magnitude of the resulting vector is taken as the coupling strength. To account for spurious findings, a null distribution is calculated by randomly shifting the time series of amplitude values. The final coupling measure is z-transformed by subtracting the mean and dividing by the standard deviation of the null distribution. | One participant excluded from behavioral analysis because they did not follow task instructions. Two participants did not complete the full study and thus were excluded from analysis. | Mean | Standard Deviation | Z-score |
|
| OG001 | Delta-beta tACS | Every participant will receive Delta-beta tACS during performance of a computerized task using NeuroConn technologies, direct current-stimulator plus |
| OG002 | Sham tACS | Every participant will receive Sham tACS during performance of a computerized task using NeuroConn technologies, direct current-stimulator plus |
|
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|
| Primary | Reaction Time for Trials With High Set-size Relative to Low Set-size | The reaction time difference between high and low set-size conditions was hypothesized to decrease when theta-gamma tACS is delivered. As a control for the placebo effect of stimulation, the difference between theta-gamma tACS and sham tACS, or placebo, was used for statistical analysis. | One participant excluded from behavioral analysis because they did not follow task instructions. | Posted | Mean | Standard Deviation | seconds | through study completion, an average of 3 weeks |
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|
|
| Primary | Delta Phase to Beta Amplitude Coupling Strength | Delta-beta tACS was hypothesized to increase cross frequency coupling strength (higher value) between the targeted frequency bands. Phase amplitude coupling between delta phase and beta amplitude was calculated for the two minute electrical brain recordings after stimulation. A null distribution was calculated by shuffling the beta amplitude time series relative to the delta phase time series and then calculating coupling strength. The outcome measure is the z-transformed value of the genuine phase amplitude coupling relative to the null distribution. | One participant excluded from coupling analysis because they did not follow task instructions. | Posted | Mean | Standard Deviation | Z-score | through study completion, an average of 3 weeks |
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| Primary | Theta Phase to Gamma Amplitude Coupling Strength | Theta-gamma tACS was hypothesized to increase cross frequency coupling strength (higher value) between the targeted frequency bands. Phase amplitude coupling between theta phase and gamma amplitude was calculated for the two minute electrical brain recordings after stimulation. A null distribution was calculated by shuffling the gamma amplitude time series relative to the theta phase time series and then calculating coupling strength. The outcome measure is the z-transformed value of the genuine phase amplitude coupling relative to the null distribution. | One participant was excluded from coupling analysis because they did not follow task instructions. | Posted | Mean | Standard Deviation | Z-score | through study completion, an average of 3 weeks |
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| Primary | Percent Correct for Trials With High Abstraction Relative to Low Abstraction | For low abstraction conditions, subjects must memorize a color to button mapping. For high abstraction conditions, subject must make a perceptual judgement on the similarity of two objects based on either texture or shape as cued by a color. The accuracy difference between high and low abstraction conditions was hypothesized to decrease when delta-beta tACS was delivered. As a control for the placebo effect of stimulation, the difference between delta-beta tACS and sham tACS, or placebo, was used for statistical analysis. | One participant excluded from behavioral analysis because they did not follow task instructions. | Posted | Mean | Standard Deviation | percent correct | through study completion, an average of 3 weeks |
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|
| Primary | Percent Correct for Trials With High Set-size Relative to Low Set-size | The accuracy difference between high and low set-size conditions was hypothesized to decrease when theta-gamma tACS is delivered. As a control for the placebo effect of stimulation, the difference between theta-gamma tACS and sham tACS, or placebo, was used for statistical analysis. | One participant excluded from behavioral analysis because they did not follow task instructions. | Posted | Mean | Standard Deviation | percent correct | through study completion, an average of 3 weeks |
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|
| 0 |
| 24 |
| 0 |
| 24 |
| 11 |
| 24 |
| EG001 | Delta-beta tACS | Every participant will receive Delta-beta tACS during performance of a computerized task using NeuroConn technologies, direct current-stimulator plus | 0 | 26 | 0 | 26 | 15 | 26 |
| EG002 | Sham tACS | Every participant will receive Sham tACS during performance of a computerized task using NeuroConn technologies, direct current-stimulator plus | 0 | 26 | 0 | 26 | 10 | 26 |
| Flickering lights | Investigations | Systematic Assessment | Mild |
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| Itching | Investigations | Systematic Assessment | Mild |
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| Burning sensation | Investigations | Systematic Assessment | Mild |
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| Scalp pain | Investigations | Systematic Assessment | Mild |
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| Neck pain | Investigations | Systematic Assessment | Mild |
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| Dizziness | Investigations | Systematic Assessment | Mild |
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| Local redness | Investigations | Systematic Assessment | Mild |
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| Sleepiness | Investigations | Systematic Assessment | Mild |
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| Headache | Investigations | Systematic Assessment | Mild |
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| Ringing noise | Investigations | Systematic Assessment | Mild |
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| Blurred vision | Investigations | Systematic Assessment | Mild |
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