High-frequency tRNS for Sleep Disturbances in Neurocognitive Disorders Due to Vascular Disease

High-frequency Transcranial Random Noise Stimulation (Hf-tRNS) for Sleep Disturbances in Neurocognitive Disorders Due to Vascular Disease

The investigators aim to 1) investigate and compare the safety, efficacy and sustainability of hf-tRNS, tACS and sham transcranial current stimulation (tCS) over left inferior parietal lobe (IPL) in mild neurocognitive disorder due to vascular disease (NCD-vascular) patients with sleep disturbances; 2) examine the relationship between the changes in sleep quality, cognitive function and brain morphometry.

Methods: Chinese right-handed mild NCD-AD patients with sleep disturbances (aged from 60 to 90 years) will be randomly assigned to a 2-week intervention of either hf-tRNS, tACS, or sham tCS, with 10 participants per arm. Before intervention, structural magnetic resonance imaging (MRI) data is used to construct individual realistic head model. Comprehensive assessments, including sleep quality, cognitive performance and blood pressure will be conducted at baseline, 2th week, 6th week and 12th week. Program adherence and adverse effects will be monitored throughout intervention.

This study aims to investigate the feasibility, safety and efficacy of hf-tRNS and tACS over left IPL for sleep disturbances and cognitive dysfunction in mild NCD-vascular patients. It wills also test the program adherence, tolerability and adverse effects of this innovative neurotechonology. Information will be helpful for in-depth understanding the relationship of "sleep disturbances-cognition" and guiding the further studies of sleep medicine and neurodegenerative diseases.

Inclusion Criteria:

• Chinese, right-handed, aged from 60 to 80 years.
• With at least one cerebrovascular risk factor, e.g., a history of hypertension defined as systolic blood pressure (BP) 140 mm Hg or higher, diastolic BP of 90 mm Hg or higher; or receiving antihypertensive medication.
• Score of Montreal Cognitive Assessment Hong Kong version (HK MoCA) range from 22 to 26 (Lu et al., 2019).
• With preserved functional abilities reflected by a Functional Assessment Questionnaire score of 7 or lower (Hajjar et al., 2020).
• With a medial temporal lobe atrophy (MTA) score < 2
• No interference with independence in everyday activities.

Exclusion Criteria:

• Previous diagnosis of dementia or stroke;
• Past history of bipolar disorders or psychosis;
• Physically frail affecting attendance to training sessions;
• Already attending regular training, such as cognitive behavioral therapy;
• Taking a psychotropic or other medication known to affect cognition (e.g. anti-dementia medication);
• Significant communicative impairments.