Mild Cognitive Impairment and Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) has been linked to increased risk for Alzheimer's disease (AD), but little prospective evidence exists on the effects of OSA treatment in preclinical AD. The objective was to determine if CPAP treatment adherence, controlling for baseline differences, predicts cognitive and everyday function after 1 year in older adults with MCI and to determine effect sizes for a larger trial. The aim of the Mild Cognitive Impairment and Obstructive Sleep Apnea (Memories 1) trial was to determine whether CPAP treatment adherence, controlling for any baseline differences in OSA severity, ApoE4, and other previously identified demographic and patient factors, might predict cognitive and everyday function after 1 year in older adults with amnestic MCI.

In this prospective open label clinical trial, primary inclusions were age 55-89 years and apnea-hypopnea index ≥ 10. Groups were: (1) MCI, OSA, and CPAP adherent (MCI+CPAP); (2) MCI, OSA, CPAP nonadherent(MCI-CPAP). There were 68 MCI+OSA participants at baseline, and 14 (21%) dropped out during the 1 year follow-up. At 1 year, n=54, with MCI+CPAP group n=29, and MCI-CPAP group n=25. Statistically significant improvements in psychomotor/cognitive processing speed in the MCI+CPAP group versus the MCI-CPAP group were observed at 1 year after adjustment for age, race, and marital status. There were small to moderate effect sizes (ES) for memory, attention, daytime sleepiness, and everyday function, favoring the MCI+CPAP group versus the MCI-CPAP group.

Eligibility Criteria:
Inclusion criteria

Participants are included in the study if all of the following criteria are met:

(1) Are able to provide written informed consent by self or legally authorized representative. MacArthur Competency Assessment Tool for Clinical Research (MacCAT-CR) will be used to assess decision making capacity; (2) OSA defined as an apnea-hypopnea index (AHI) ≥10, using either a clinical split- or whole-night polysomnography. We chose an AHI cut-off of ≥10 as opposed to ≥15, the conventional cut-off for moderate OSA because split-night studies underestimate the AHI; (3) education-adjusted scores of 28-35 on the modified Telephone Interview for Cognitive Status; (4) 0-0.5 on the Clinical Dementia Rating (CDR); (5) 24-30 on the Mini-Mental State Examination (MMSE); (6) memory impairment approximately 1.0-1.5 standard deviations below normal (adjusted for age and education), determined by scores on the Logical Memory II test; (7) performance approximately 1.0-1.5 standard deviations below normal (adjusted for age and education) in no more than one cognitive domain in addition to memory; (8) medications stable for at least 4 weeks; washout from psychoactive medications (e.g., excluded anti-depressants, neuroleptics, chronic anxiolytics, and sedative hypnotics) for 4 weeks; (9) score of ≤28 on the 21-item Beck Depression Inventory II; (10) a study partner who spends at least 10 hours per week in phone or in-person contact with participant; (11) visual and auditory acuity for testing; (12) 6 or more grades of education completed, or a history to exclude intellectual disability; and (13) English fluency.

Exclusion criteria

Patients are excluded from participating in this study if 1 or more of the following criteria are met:

(1) significant neurologic disease other than MCI; (2) MRI exclusions, e.g. metal; (3) psychiatric disorders, including uncontrolled major depression, bipolar disorder, or schizophrenia; (4) history of alcohol dependence within 6 months; (5) current significant unstable medical condition; (6) participation in studies involving neuropsychological testing; (7) currently receiving CPAP; (8) requiring oxygen during CPAP; (9) dementia indicated by impairment in 3-5 age and education adjusted cognitive domains.