An interventional study of tDCS with cognitive training programme in Transcranial Direct Current Stimulation, Post-Concussion Syndrome and Functional Magnetic Resonance Imaging, sponsored by The Hong Kong Polytechnic University. Recruiting at 1 site in Hong Kong. Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-09-25.
Sponsored by The Hong Kong Polytechnic University · Not applicable, Interventional, and Treatment
Globally, 10 million new traumatic brain injury (TBI) cases are estimated annually, with mild traumatic brain injury (mTBI) accounting for 75-90% of all TBI cases. It is estimated that 40-80% of individuals with mTBI may experience the post-concussion syndrome (PCS), which is characterized by a range of physical, cognitive, and emotional symptoms. Although the underlying basis of cognitive dysfunction of patients with persistent PCS remains to be clarified, converging evidence shows that the clinical symptoms is underpinned by abnormal neural information processing as a result of axonal injury due to mTBI. Recent studies have demonstrated abnormalities in both structural and functional cortical connectivity, and a loss of cortical excitability-inhibitory (E/I) balance after TBI. Yet, there is no consensus for treating chronic symptoms of concussion, and PCS remains a chronic and highly disabling condition. One potential treatment option is transcranial direct current stimulation (tDCS), a non-invasive brain stimulation technique that has been shown to modify behavior by enhancing connectivity between targeted brain areas. However, research on the therapeutic effect of tDCS on PCS symptoms is limited, and the neurologic mechanisms underlying its effects are not well understood. The proposed study aims to address these knowledge gaps by examining the effects of tDCS on the central nervous system function in patients with PCS, with a specific focus on functional cortical connectivity and cognitive functions such as processing speed and executive function. The study also aims to add value to existing evidence by potentially opening new directions for designing intervention programs for the treatment of PCS after mTBI.
141 studies on the registry are indexed under Post-Concussion Syndrome; 34 are open to participants now.
This study's planned enrollment of 40 is below the median of 52 across 114 interventional studies indexed under Post-Concussion Syndrome.
Browse Post-Concussion Syndrome studies →The Hong Kong Polytechnic University is the lead sponsor of 679 studies on the registry; 257 are open to participants now.
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For active-tDCS condition, participants will receive stimulation on the dorsolateral prefrontal cortex with ramp up and ramp down mode for 10 seconds, eliciting a tingling sensation on the scalp that fades over seconds.
Device: tDCS with cognitive training programme
For sham-tDCS condition, participants will receive initial stimulation with ramp up and ramp down mode for 30 seconds, eliciting a tingling sensation on the scalp then it will be discontinued.
Device: tDCS with cognitive training programme
Participants will complete tDCS over 10 sessions in 2 weeks (once per day, for 10 consecutive working days), while performing the executive function training tasks. The training session will last for 20 minutes and it is comprised of 5 exercises targeting at information processing speed and executive function capacities. Each exercise lasts for approximately 4 minutes, totaling approximately 20 minutes.
Average standardised score of executive function tests
The executive function of the PCS subjects will be assessed using the Executive Composite score, which combines scores from various executive function tests.Simple-task processing speed will be evaluated using the CANTAB® 5-choice Reaction Time (RTI) task, which measures the ability to focus on relevant information while ignoring distractions. It requires participants to react as soon as a yellow dot appears on screen. Complex-task processing speed will be assessed using the computerized version of the Wisconsin Card Sorting Test (WCST), which assesses cognitive flexibility. The test requires subjects to correctly match the response cards with several stimulus cards according to feedback provided based on a rule. The mean reaction time is calculated for the trials giving a correct answer during WCST. The reaction time measured from both tasks will be converted to standard scores and averaged to yield an executive composite score. Lower scores indicate poorer executive functioning.
Time frame: First day of intervention, 1 day after the last day of intervention (2 time points, up to 2 weeks)
Change in CANTAB® cognitive test - Reaction Time (RTI)
RTI assesses motor and mental response speeds, reaction time, response accuracy and impulsivity. It consists of 30 trials with five potential targets and requires participants to make flexible responses as fast as possible to the target stimulus (shown in yellow). Specifically, movement and reaction time will be measured, where shorter duration reflects faster processing speed.
Time frame: First day of intervention,1 day after the last day of intervention (2 time points, up to 2 weeks)
Change in CANTAB® cognitive test - Multitasking Test (MTT)
MTT assesses the ability to resolve the interference of task-irrelevant information (stroop-like effect). The test displays an arrow which can appear on either the left or right side of the screen and can point to either the left or right side. In each trial, participants are presented with a cue that indicates which button to press according to two different rules. And the rules that participants have to follow may change from trial to trial in a randomized order. Participant's response latencies and error scores will be measured.
Time frame: First day of intervention,1 day after the last day of intervention (2 time points, up to 2 weeks)
Change in CANTAB® cognitive test - Spatial Working Memory (SWM)
SWM assess the memory ability of visuospatial information. Participants are required to search the tokens from a number of boxes but not pressing the boxes which tokens have been found. Errors (lower scores indicate lower repetition on pressing the same boxes that token has been found) and strategy (lower scores suggest higher strategy use in begin of choosing the same boxes) will be measured.
Time frame: First day of intervention,1 day after the last day of intervention (2 time points, up to 2 weeks)
Exploratory mediator - default mode network (DMN) activation
The DMN activation, indexed by fMRI resting state data will be assessed. Neuroimaging data will be acquired from the whole brain using a 64-channel head coil on a 3T Siemens MRI scanner. Resting-state data will be registered to each participant's high-resolution structural image and then normalized into the standard Montreal Neurological Institute (MNI) space. Mediation analyses will be performed to determine if the enhanced network organization in PCS patients, as indexed by DMN activation, will mediate the beneficial effect of tDCS
Time frame: First day of intervention,1 day after the last day of intervention (2 time points, up to 2 weeks)
Exploratory mediator - excitability-inhibitory (E/I) ratio
The E/I ratio, indexed by MRS data will be assessed. The MRS acquisition protocol is adopted from Sapey-Triomphe and the colleagues. Magnetic resonance spectra will be acquired using the Hadamard Encoding and Reconstruction of MEGA-Edited Spectroscopy (HERMES) sequence, allowing for simultaneous quantification of GABA + and Glx (glutamine and glutamate). The MRS acquisition parameters will be set as follows: 320 averages, TR = 2000 ms, TE = 80 ms, 2048 data points, 2000 Hz spectral width, MOIST water suppression, 90°excitation/180°refocusing pulses, 20 ms editing pulses at frequencies 1.9 ppm for GABA. Interleaved Water Reference correction will be used to limit the effect of scanner drift. Twenty unsuppressed water reference scans (at TE = 80 ms) will also be acquired. Mediation analyses will be performed to determine if the enhanced network organization in PCS patients, as indexed by E/I balance, will mediate the beneficial effect of tDCS
Time frame: First day of intervention,1 day after the last day of intervention (2 time points, up to 2 weeks)
Started Sep 2025 (actual). Primary completion is estimated for Aug 2027, 23 months after the start.
Of 54 non-industry interventional studies with no phase under Post-Concussion Syndrome, half reached primary completion within 40 months of starting (the median), counting those still running; a quarter within 24 and three quarters within 58. This study's planned 23 months is below that.
Counting every sponsor, half of 56 studies reached it within 40 months; a quarter within 23 and three quarters within 69.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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