Background: Sleep disturbances are highly prevalent in ageing population and patients with age-related neurodegenerative diseases, which severely affect cognition and even lead to accumulated amyloid-β (Aβ). At present, non-pharmacological interventions for sleep disturbances in dementia patients are accepted as first line of treatment, of which the evidence from clinical trials is very limited. Encouraging results from recent studies on transcranial direct current stimulation (tDCS) showed moderate positive effects on sleep quality in preclinical Alzheimer's disease (AD). Compared to tDCS, high-definition transcranial alternating current stimulation (HD-tACS) enables the entrainment of neuronal activities with optimized focality through injecting small electric current with a specific frequency and has significant enhancement effects on slow wave activities. Objectives: The investigators aim to 1) investigate and compare the safety, efficacy and sustainability of 40 Hz HD-tACS and HD-tDCS over left dorsolateral prefrontal cortex (DLPFC) in mild neurocognitive disorder due to AD (NCD-AD) patients with sleep disturbances; 2) examine the relationship between the changes in sleep quality, cognitive function and saliva Aβ levels. Methods: Chinese right-handed mild NCD-AD patients with sleep disturbances (aged from 60 to 90 years) will be randomly assigned to a 4-week intervention of either HD-tACS, HD-tDCS, or sham HD-tCS, with 33 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 saliva Aβ levels will be conducted at baseline, 4th week, 8th week, 12th week and 24th week. Program adherence and adverse effects will be monitored throughout intervention. Data analysis: The primary outcomes will be the changes in sleep quality and memory performance with modality-driven paradigms (HD-tACS, HD-tDCS, sham HD-tCS), and comparisons of group differences across different time points. Secondary outcomes will be the changes objective sleep pattern, global cognition, saliva Aβ levels and quality of life. Intention-to-treat analysis will be carried out. Changes of efficacy indicators from baseline to each follow up point will be tested with mixed effect model. Significance: This study aims to investigate the feasibility, safety and efficacy of HD-tACS and HD-tDCS over left DLPFC for sleep disturbances and cognitive dysfunction in mild NCD-AD 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-amyloid deposition" and guiding the further studies of sleep medicine and neurodegenerative diseases.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
99
High-definition transcranial current stimulation (HD-tCS) is delivered by a battery driven direct current stimulator (DC-Stimulator Plus, NeuroConn, Ilmenau, Germany) through a central anodal electrode surrounded by four return cathodal electrodes.
The Chinese University of Hong Kong
Hong Kong, Hong Kong
Pittsburg Sleep Quality Index (PSQI)
The PSQI is a 19-item questionnaire that includes seven areas of subjective sleep quality and patterns in adults over the last month including the following components: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, SDs, use of sleeping medications, and daytime dysfunction (Buysse et al., 1988). Each item in the scale is scored from 0 to 3 scale (0 = no difficulty; 3 = severe difficulty). The scores are added to yield a global score ranging from 0 to 21 (0 = no difficulty; 21 = severe difficulties in all areas). This scale has good reliability and validity psychometrics and is widely used in research: Cronbach's alpha (0.77 to 0.83), sensitivity (89.6%), specificity (86.5%)(Buysse et al., 1988). Greater score of PSQI indicates worse sleep quality.
Time frame: 24 weeks
Delayed recall of words
Word-list learning test (WLLT), consisting of sixteen semantically non-associated words, is presented consecutively over three free trials of immediate recall, a 20-min delayed recall (to prevent recency effects) (Lu et al., 2018). The raw numbers of words recalled are used to assess the memory function.
Time frame: 24 weeks
Efficacy evaluated by attention function performance
Attention network function measured by computerized attention network test (ANT)
Time frame: 24 weeks
Efficacy evaluated by executive function performance
Executive function is measured by category verbal fluency test (CVFT).
Time frame: 24 weeks
Efficacy evaluated by saliva Aβ40 and Aβ42 levels
The levels of Aβ40 and Aβ42 in the saliva samples will be quantified by enzyme-linked immunosorbent assay (ELISA)-type assays (Aurin Biotech, Inc.).
Time frame: 24 weeks
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