The AHA/ASA and DSM-V diagnostic criteria for vascular cognitive impairment identify cases with predominant vascular pathology.

BACKGROUND: There are major challenges in determining the etiology of vascular cognitive impairment (VCI) clinically, especially in the presence of mixed pathologies, such as vascular and amyloid. Most recently, two criteria (American Heart Association/American Stroke Association (AHA/ASA) and Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V)) have been proposed for the clinical diagnosis of VCI but have not as yet been validated using neuroimaging. AIMS: This study aims to determine whether the AHA/ASA and DSM-V criteria for VCI can distinguish between cases with predominantly vascular pathology and cases with mixed pathology. METHODS: A total of 186 subjects were recruited from a cross-sectional memory clinic-based study at the National University Hospital, Singapore. All subjects underwent clinical and neuropsychological assessment, magnetic resonance imaging (MRI) and carbon 11-labeled Pittsburgh Compound B ([11C] PiB) positron emission tomography (PET) scans. Diagnosis of the etiological subtypes of VCI (probable vascular mild cognitive impairment (VaMCI), possible VaMCI, non-VaMCI, probable vascular dementia (VaD), possible VaD, non-VaD) were performed following AHA/ASA and DSM-V criteria. Brain amyloid burden was determined for each subject with standardized uptake value ratio (SUVR) values ⩾1.5 classified as amyloid positive. RESULTS: Using κ statistics, both criteria had excellent agreement for probable VaMCI, probable VaD, and possible VaD (κ = 1.00), and good for possible VaMCI (κ = 0.71). Using the AHA/ASA criteria, the amyloid positivity of probable VaMCI (3.8%) and probable VaD (15%) was significantly lower compared to possible VaMCI (26.7%), non-VaMCI (33.3%), possible VaD (73.3%), and non-VaD (76.2%) (p < 0.001). Similarly, using the DSM-V criteria, the amyloid positivity of probable VaMCI (3.8%) and probable VaD (15%) was significantly lower compared to possible VaMCI (26.3%), non-VaMCI (32.1%), possible VaD (73.3%), and non-VaD (76.2%) (p < 0.001). In both criteria, there was good agreement in differentiating individuals with non-VaD and possible VaD, with significantly higher (p < 0.001) global [11C]-PiB SUVR, from individuals with probable VaMCI and probable VaD, who had predominant vascular pathology. CONCLUSION: The AHA/ASA and DSM-V criteria for VCI can identify VCI cases with little to no concomitant amyloid pathology, hence supporting the utility of AHA/ASA and DSM-V criteria in diagnosing patients with predominant vascular pathology. DATA ACCESS STATEMENT: Data supporting this study are available from the Memory Aging and Cognition Center, National University of Singapore. Access to the data is subject to approval and a data sharing agreement due to University policy.

Long-term neurobehavioral correlates of brain cortical microinfarcts in a memory clinic cohort in Singapore.

BACKGROUND: Cortical cerebral microinfarcts are a small vessel disease biomarker underlying cognitive impairment and dementia. However, it is unknown whether cortical cerebral microinfarcts are associated with neuropsychiatric disturbances, and whether its effects are independent of conventional small vessel disease markers. AIMS: We investigated the associations of cortical cerebral microinfarcts burden with incidence and progression of neuropsychiatric subsyndromes in a memory clinic cohort of elderly in Singapore. METHODS: In this prospective cohort, 496 subjects underwent detailed neuropsychological and clinical assessments, 3T brain MRI, and Neuropsychiatric Inventory assessment at baseline and two years later. Cortical cerebral microinfarcts and other small vessel disease markers, including white matter hyperintensities, lacunes, and microbleeds, were graded according to established criteria. Neuropsychiatric symptoms (NPS) were clustered into subsyndromes of hyperactivity, psychosis, affective, and apathy following prior findings. Functional decline was determined using the clinical dementia rating (CDR) scale. RESULTS: The presence of multiple cortical cerebral microinfarcts (≥2) was associated with higher total NPS scores (ß = 4.19, 95% CI = 2.81-5.58, p < 0.001), particularly hyperactivity (ß = 2.01, 95% CI = 1.30-2.71, p < 0.01) and apathy (ß = 1.42, 95% CI = 0.65-2.18, p < 0.01) at baseline. Between baseline and year-2, multiple cortical cerebral microinfarcts were associated with accelerated progression in total NPS scores (ß = 0.29, 95% CI = 0.06-0.53, p = 0.015), driven by hyperactivity (ß = 0.45, 95% CI = 0.17-0.72, p < 0.01). Subjects with multiple cortical cerebral microinfarcts also had a faster functional decline, as measured with the CDR-sum-of-boxes scores, when accompanied with progression (ß = 0.31, 95% CI = 0.11-0.51, p < 0.01) or hyperactivity in total NPS (ß = 0.34, 95% CI = 0.13-0.56, p < 0.01). CONCLUSION: Cortical cerebral microinfarcts are associated with incidence and progression of geriatric neurobehavioral disturbances, independent of conventional small vessel disease markers. The impact of incident cortical cerebral microinfarcts on neurocognitive and neuropsychiatric trajectories warrants further investigations.

Pilot Evaluation of the Informant AD8 as a Case-Finding Instrument for Cognitive Impairment in General Practitioner Clinics of Singapore: A Brief Report.

BACKGROUND: Case-finding services using a composite total risk score (TRS) and the informant AD8 have been previously recommended to detect cognitive impairment (CI) in government subsidized primary health care centers of Singapore (ie, polyclinics). OBJECTIVE: We compared the feasibility of implementing the services recommended for government-subsidized primary health care in private, primary health care service providers such as general practitioner (GP) clinics. METHOD: 123 patients ≥60 years of age were recruited from 2 GP clinics within Singapore. Trained research personnel administered the AD8 to informants. Patients of the present study were compared against a random sample of 123 patients selected from polyclinics. RESULTS: Significantly higher positive screening rates (AD8 ≥3) were found among patients in polyclinics than GP clinics (P < .001). Patients attending polyclinics reported more comorbid medical issues such as subjective cognitive complaint (P < .001) and heart disease (P < .001). The TRS of patients attending polyclinics was significantly higher than those attending GP clinics (P < .001), indicating a higher proportion of patients at risk of CI in polyclinics. Therefore, patients attending polyclinics were found to have higher AD8 scores compared with patients in GP clinics (P < .001). CONCLUSION: Compared with GP clinics, polyclinics may be more suited to provide case-finding services for the detection of CI in primary health care.

Pilot Evaluation of a Dementia Case Finding Clinical Service Using the Informant AD8 for At-Risk Older Adults in Primary Health Care: A Brief Report.

BACKGROUND: An AD8 cut-off score of ≥4 has been reported to successfully detect 90% of dementia cases in elderly patients aged 75 years and above. OBJECTIVE: We investigated the benefits of a pilot clinical service conducted in primary care that used the AD8 to identify patients with dementia in an at-risk population. METHOD: Patients ≥75 years of age were recruited from a primary health care center in Singapore. Trained nurses administered the AD8 to informants of eligible patients. Patients screened positive (AD8 score ≥4) were referred to specialist memory clinics by primary health care physicians for further evaluation. RESULTS: Of the 551 eligible patients in the primary health care center, 168 (30.5%) consented and the AD8 was administered to their informants. Among the recruited patients, 23 (13.7%) were screened positive and 7 (30.4%) of them accepted referrals to specialist memory clinics. The clinical diagnoses for these patients were as follows: no cognitive impairment (NCI) (n = 1), cognitive impairment no dementia (CIND) (n = 5), and dementia (n = 1). Most of the (98.8%) nurses found AD8 user-friendly and could track functional decline. Eighteen of the 23 (78.3%) primary health care physicians who referred patients to specialist memory clinics considered the AD8 useful for facilitating referrals. The remaining physicians (21.7%) preferred performance-based tests. CONCLUSION: The AD8 is easily administered by nurses and useful to a majority of primary health care physicians to generate referrals. However, physician preference for performance-based tests and a lower prevalence of dementia in the at-risk population may indicate the need to consider a "2-pronged assessment approach" that combines both performance-based and informant-based brief tests to reduce false positive rates and better detect dementia.

Metabolic syndrome among ethnic South Asian patients with ischemic stroke and comparison with ethnic Chinese patients: the Singapore General Hospital experience.

BACKGROUND: South Asians are the largest ethnic group in the world, yet there are no data on metabolic syndrome (MetS) among ethnic South Asian patients with ischemic stroke. Ethnic differences in the prevalence of MetS are known to exist. METHODS: We studied 126 consecutive ethnic South Asian patients and 126 age-, sex-, and diabetes-matched ethnic Chinese patients admitted with acute ischemic stroke. RESULTS: The prevalence of MetS among ethnic South Asian patients, at 61%, was significantly higher than among ethnic Chinese patients (47%) (P < .001). Of note, mean high-density lipoprotein was lower among ethnic South Asian compared with ethnic Chinese patients (P = .002). CONCLUSION: We describe a high burden of MetS among ethnic South Asian patients, which was significantly greater than that found among ethnic Chinese patients.