Effects of t-DCS and Cognitive Training on Apathy in Elderly With Minor Neurocognitive Impairment

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique using a low intensity electric current to modify cortical excitability. Apathy is a pervasive neuropsychiatric symptom characterized by a reduction in goal-directed behavior and activity that persists over time and causes identifiable functional impairment. The aim of this study is to evaluate the effects of repeated sessions of tDCS combined with simultaneous cognitive training on apathy in older people with minor neurocognitive disorders.

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique using a low intensity electric current to modify cortical excitability. There is growing interest for tDCS for psychiatric illnesses, notably for depression.

Apathy is a pervasive neuropsychiatric symptom characterized by a reduction in goal-directed behavior and activity that persists over time and causes identifiable functional impairment. tDCS could be a promising new area for non-pharmacological treatment of apathy.

The aim of this study is to evaluate the effects of repeated sessions of tDCS combined with simultaneous cognitive training on apathy in older people with minor neurocognitive disorders. For this, 30 apathetic subjects with minor neurocognitive disorders will be included and randomized between two groups. The intervention group will follow sessions of tDCS combined with a simultaneous cognitive training on tablet. The control group will follow cognitive training with a combined sham tDCS. Intervention will last for 4-week with 3 sessions per week (12 sessions). Stimulation will be performed with Startim 20 (Neuroelectrics®) which is approved by the European Union as a Class IIa medical device and meeting European safety standards. Stimulation will last for 20 minutes and the dorsolateral prefrontal cortex (F3) will be targeted. For the intervention group, the electric current will be 2mA. Assessments will be done at baseline, just after the end of intervention and 3 months after intervention. Apathy, daily functional motor behaviors, cognitive functions and fatigue will be assessed with clinician assessment, self-administered questionnaires, ambulatory actigraphy and cognitive tests. The assessments and the intervention will be done by different people. Study will be a double-blind randomized controlled trial.

Eligibility Criteria:
Inclusion Criteria:

* Age ≥ 65 years
* Subject consulting in one of the investigating centers
* Clinical diagnosis of Minor Neurocognitive Disorder according to DSM 5 criteria (APA, 2013)
* Apathetic syndrome defined according to the Diagnostic Criteria for Apathy (Miller \& al., 2021)
* Subject who can read and write French
* Subjects who are beneficiaries of a social security plan
* Signature of free and informed consent

Exclusion Criteria:

* Current clinical diagnosis of a depressive episode characterized by DSM 5 criteria (APA, 2013)
* Known diagnosis of schizophrenia, bipolar disorder, substance abuse or dependence
* Significant sensory or motor impairment
* Subject under guardianship, conservatorship, or conservatorship
* Active smoking or smoking cessation of less than one year
* Contraindications to the practice of tDCS: history of intracranial hypertension, neurosurgery, metallic implant at the cephalic level, pacemaker
* Unbalanced epilepsy
* Severe somatic disease not stabilized
* Previous use of tDCS (problem of maintaining the integrity of the blinding procedure)
* Scalp skin disease
* Concurrent participation in another drug research study or any other study that may interfere with study results