Study Evaluating the Effect of Transcranial Direct Current Stimulation (tDCS) Targeting the Right Inferior Frontal Gyrus on Inhibitory Control in Patients With PSP

What this study is about

The study's own summary, as published on ClinicalTrials.gov. Underlined terms have a short explanation.

Progressive supranuclear palsy (PSP) is a rare neurodegenerative disease with a prevalence estimated at 6 per 100,000 in France and a rapidly progressive course. In its classic form (known as the Richardson type), it presents with a predominantly axial Parkinsonian syndrome, postural instability with early falls, oculomotor disorders, and cognitive and behavioral disturbances. Apart from levodopa, which may provide a modest improvement in Parkinsonian syndrome in some patients, the current therapeutic approach relies primarily on rehabilitation techniques, with no proven efficacy. Cognitive-behavioral symptoms are common in this disease and are primarily characterized by impaired executive functions, linked to dysfunction of the frontal cortex. They often have a devastating effect on quality of life, are associated with an increased risk of falls, and represent a considerable burden for caregivers. Among these symptoms, apathy is the most commonly described symptom. Impulsivity, associated with impaired inhibitory control, is present in 32-74% of cases and may coexist with apathy. Cognitive and behavioral inhibition depends on a complex brain network that includes, among others, the right inferior frontal gyrus (IFG), the dorsolateral prefrontal cortex, the supplementary motor area, the motor cortex, and the basal ganglia. It has recently been shown that patients with PSP have impaired functional connectivity between the right LFC and other brain structures in the network, and that neurotransmitter deficits in the right LFC correlate with their impulsivity Alongside pharmacological approaches, non-invasive brain stimulation techniques are rapidly expanding as a potential therapeutic tool. Transcranial direct current stimulation (tDCS), by modulating cortical excitability, is a promising technique. It is simple to administer and has demonstrated efficacy in several clinical settings. Furthermore, a recent meta-analysis of 45 clinical studies shows that single or repeated tDCS sessions could modestly but significantly improve the inhibitory response-measured by reaction time in the stop-signal paradigm-especially when active (anodal) stimulation was applied to the right GFI. These studies primarily involved healthy subjects?healthy subjects People who do not have the condition being studied who are allowed to take part. Some studies include both people with the condition and healthy volunteers; others may enrol only healthy volunteers.. A few studies have examined the effects of tDCS in neurodegenerative diseases and in PSP. These studies are still preliminary, involving small sample sizes, but are encouraging. Among these, a randomized?randomized Participants are assigned to the study groups by chance, like a coin toss, rather than chosen by the doctor or the participant. This is done so the groups are comparable. study comparing tDCS to sham?sham A procedure designed to resemble the real procedure, for example the same visit and equipment, without its active part. It is the procedure equivalent of a placebo. tDCS demonstrated a beneficial effect of a single-session tDCS session targeting the dorsolateral prefrontal cortex on verbal fluency in patients with PSP. The hypothesis of our study is that applying tDCS stimulation over the right GFI will improve certain cognitive functions and reduce behavioral impulsivity in patients. Very little data on tDCS in PSP is available to date. Only three studies have been published. With very different designs-including only one randomized trial comparing tDCS to sham tDCS-these studies evaluated the effects of tDCS applied to the dorsolateral prefrontal cortex or to motor and premotor areas on language and motor symptoms, respectively. In this randomized, double-blind?double-blind Two types of people involved in the study do not know which intervention a participant is receiving. The ClinicalTrials.gov record specifies who is masked, for example participants, care providers, investigators or outcome assessors., controlled study, the investigators propose to explore the effects of tDCS on the right GFI on executive functions and, more specifically, on inhibitory control. Another strength of our study is that only patients with proven frontal cerebral hypometabolism on FDG-PET?PET A scan in which a small amount of a radioactive tracer is injected so that activity in tissues can be seen. Often combined with a CT or MRI scan.-MRI?MRI A scan that uses magnets and radio waves, not X-rays, to make detailed pictures of the inside of the body. Some implants and metal objects mean a person cannot have one. will be included, which will allow us to test the effect of tDCS on a clearly dysfunctional neural network. Furthermore, as a secondary objective?secondary objective An additional result the study measures alongside the primary outcome, for example quality of life or a laboratory value., the investigators will be able to assess whether the effects of tDCS depend on the intensity and/or topography of cerebral hypometabolism. The neurophysiological effects of a single tDCS session appear to last up to 60 to 90 minutes. In this proof-of-concept study, the assessment tests were deliberately chosen for their short administration time and low test-retest effect. Finally, the Stop Signal Test, already used in this population, is widely used and well-standardized. This pilot study will provide initial data on the cognitive and motor effects of a tDCS session on the GFI, with a focus on inhibition. Given the limited effectiveness of symptomatic treatments-particularly pharmacological ones-having a new option capable of improving cognitive and/or behavioral performance would have a significant impact on the quality of life of patients and their families. tDCS has the advantage of being easily accessible and generally well-tolerated by patients and could eventually be administered in patients' homes. If our study demonstrates an improvement in certain cognitive/motor functions, it would lead to a larger-scale study with repeated sessions to assess its benefits over a longer period. Finally, if an improvement in executive functions is demonstrated in PSP, this could apply to other neurodegenerative diseases.

Eligibility

The criteria exactly as listed on ClinicalTrials.gov. Only the study team can say whether they apply to you.

Study description and what participation involves

The registry record has no detailed description beyond the summary above.