Sleep Apnea and Cognitive Function in Subjects With Subjective or Mild Cognitive Impairment

Study Overview
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Brief Summary
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Obstructive sleep apnea (OSA) is recurrent episodes of partial or complete obstruction of the upper airway during sleep that causes intermittent hypoxia and sleep fragmentation and leads to cardiometabolic and neurocognitive sequelae. Chronic intermittent hypoxia, sleep fragmentation of OSA, and insufficient sleep have been significantly associated with higher risks of neurocognitive impairment, including mild cognitive impairment (MCI) and Alzheimer's disease. Thus, sleep and circadian function might be modifiable neurocognitive impairment factors. The significance of the study is to understand the relationships of MCI with sleep apnea and sleep-related symptoms, which helps pave the groundwork for further research.

Detailed Description
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Obstructive sleep apnea (OSA) is recurrent episodes of partial or complete obstruction of the upper airway during sleep that causes intermittent hypoxia and sleep fragmentation. Chronic intermittent hypoxia, sleep fragmentation of OSA, and insufficient sleep have been significantly associated with higher risks of neurocognitive impairment, including mild cognitive impairment (MCI) and Alzheimer's disease. Thus, sleep and circadian function might be modifiable neurocognitive impairment factors. A recent review of 11 studies involving 5826 subjects [96% with OSA and 9% with MCI or Alzheimer's disease] suggests OSA is a modifiable risk factor for cognitive decline. Thus, improving sleep, sleep apnea and circadian function could be a high-value intervention target to alleviate cognitive impairment and decline in subjects with MCI. The study aims to understand the relationships of prevalent sleep apnea and sleep-related symptoms with neurocognitive status in patients who presented with the main complaint of neurocognitive impairment ( to the Memory clinic). The information would help pave the groundwork for further research.

Official Title
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Exploring the Association of Sleep Apnea With Cognitive Function in Subjects With Subjective or Mild Cognitive Impairment

Conditions
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Obstructive Sleep Apnea, Mild Cognitive Impairment, Subjective Cognitive Impairment

Intervention / Treatment
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* Diagnostic Test: Home Sleep Apnea test (HSAT)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: (i) Aged 18 years and above (ii) Clinical diagnosis of mild cognitive impairment (MCI) based on Petersen's criteria. The criteria include the following: (1) memory problems, (2) objective memory disorder, (3) absence of other cognitive disorders or repercussions on daily life, (4) normal general cognitive function and (5) absence of dementia OR, (iii) Diagnosis of subjective cognitive impairment, based on the subject's own complaint of cognitive impairment but with an unremarkable assessment of the Hong Kong version of Montreal Cognitive Assessment scores (iv) Able to speak and read Chinese (v) Adequate visual and auditory to perform a cognitive test Exclusion Criteria: (i) Diagnosed psychiatric illness with or without medication, e.g. major depressive disorder. (ii) Other clear organic causes of cognitive impairment, e.g. old stroke, brain tumour, dementia with Lewy body, Parkinson's disease, normal pressure hydrocephalus, neurosyphilis, autoimmune encephalitis, substance abuse, history of alcohol abuse. (iii) Diagnosis of major unstable illness or cancer on active treatment (iv) Unable to perform Home Sleep Apnea Test (v) Those patients who require legal guardians

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| MCI or SCI patient<br>At baseline: Cognitive tests, questionnaire, and Home Sleep Apnea Test will be done. | Diagnostic Test: Home Sleep Apnea test (HSAT)<br>* Patient will received HSAT at baseline<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sleep study parameters | Measured by Apnea Hypopnea Index (AHI). Score less than 5 is no OSA, score 5-15 is categorized as mild OSA, 15-30 is categorized as moderate OSA, and>30 is severe OSA. | Baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Daytime sleepiness | Measured by Epworth Sleepiness Scale. Each item asks the individual to rate their daytime sleepiness. The total score ranges from 0 to 24. The higher the scores, the greater the severity of daytime sleepiness | Baseline | 
| Sleep apnea symptoms | Measured by Pittsburgh Sleep Quality Index. Each of the sleep components yields a score ranging from 0 to 3, with 3 indicating the greatest dysfunction. The sleep component scores are summed to yield a total score ranging from 0 to 21, with the higher total score indicating worse sleep quality. | Baseline | 
| Insomnia symptoms | Measured by Severe Insomnia Index. Each item asks the individual to rate the severity of his or her symptoms with a 4-point Likert scale. The total score ranges from 0 to 28. The higher the scores the greater the severity of insomnia | Baseline | 
| Sleep profile and quality | Measured by Pittsburgh Sleep Quality Index. Each of the sleep components yields a score ranging from 0 to 3, with 3 indicating the greatest dysfunction. The sleep component scores are summed to yield a total score ranging from 0 to 21, with the higher total score indicating worse sleep quality. | Baseline | 
| Depression symptoms | Measured by Geriatric Depression Scale - short form. The score ranges from 0 to 15. The higher the scores the more severe of depression. | Baseline | 
| Activities of Daily Living | Measured by Instrumental Activities of Daily Living Scale (I.A.D.L.) and Simplified Barthel ADL index. The total score of I.A.D.L ranges from 0 to 8, 0 is the worst possible score, while 8 is the best possible score. The total score of A.D.L ranges from 0 to 20, 0 is the worst possible score, while 20 is the best possible score. | Baseline | 
| Cognitive function | Measured by Montreal Cognitive Assessment (MoCA) score and ADAS-Cog. The scores of MoCA range from 0 to 30, 0 is the worst possible score and 30 is the best possible score. The scores of ADAS-Cog range from 0 to 70, 0 is the best possible score and 70 is the worst possible score. | Baseline | 
| Ability to inhibit cognitive interference | Measured by Stroop Colour and Word Test (SCWT). Scored by time and error. A longer time indicates a worst score, while a shorter time indicates a better score. | Baseline |