ENhancing Outcomes in Cognitive Impairment Through Use of Home Sleep ApNea Testing

Inclusion Criteria: * Evidence of cognitive impairment by any one of: (i) Montreal Cognitive Assessment (MoCA) score of 13-28, or (ii) Mini Mental State Examination (MMSE) score of 18-30, or (iii) Toronto Cognitive Assessment (TorCA) score ≤281. * A diagnosis of: (i) Single-domain amnestic or multiple cognitive domain (with one feature being amnestic) Mild Cognitive Impairment due to Alzheimer's disease (AD); or (ii) Probable AD dementia; or (iii) Possible AD dementia due to limited concomitant cerebrovascular disease; or (iv) Probable Vascular dementia or Vascular Mild Cognitive Impairment, as per the 2011 American Heart Association Scientific Statement; or (v) Patients with a suspected neurodegenerative condition known to be associated with non-OSA sleep disorders (e.g. Parkinson's disease-related dementia and dementia with Lewy Bodies); and/or (vi) Mixed disease * Have the competency to provide informed consent, or the availability of a substitute decision maker/caregiver who can provide consent (if needed). * The availability of a caregiver to assist in the completion of HSAT or iPSG, if needed. Exclusion Criteria: * Prior diagnosis of OSA within the last 2 years * Patients already using CPAP or a dental appliance for previously diagnosed OSA. * A known contraindication for the use of the HSAT that will be used in this study: (a) Moderate to severe pulmonary disease or congestive heart failure that could compromise the validity of the HSAT results (in users of the ApneaLink); (b) Permanent pacemaker or history of sustained non-sinus cardiac arrhythmia (in users of the WatchPAT). * Any medical device that would interfere with the placement of the HSAT * Significant physical impairment or language barrier that would restrict the ability to use the HSAT or complete the study assessments.