The short-term memory binding test differentiates elderly with subjective cognitive decline from healthy controls in a Brazilian cohort

Background Several epidemiological studies have shown that individuals with subjective cognitive decline (SCD) experience a higher risk of progression to dementia. The Short-term Memory Binding (STMB) test seems to be useful in detecting early cognitive changes in this population. Objective: To compare the performance in the STBM test of healthy controls (HC) and elderly with SCD. Methods The sample consisted of elderly recruited from a Geriatric outpatient clinic and a healthy aging center. Dementia, mild cognitive impairment, major psychiatric disorder or use of psychotropic drugs were the exclusion criteria. Subjects were divided into HC and SCD groups. The volunteers were evaluated with the Clinical Dementia Rating scale (CDR), Functional Activities Questionnaire, Mini Mental Status Examination (MMSE), Montreal Cognitive Assessment (MoCA), Brief Cognitive Screening Battery, a standard neuropsychological battery and the STMB test. SCD evaluation was based on the Cognitive Function Instrument (CFI). The Geriatric Anxiety Inventory (GAI) and Geriatric Depression Scale (GDS) were applied for the screening of anxiety and depression symptoms. Results Initially 94 elderly individuals were evaluated. Sixty-four had at least one cognitive test z-score at -1.5 SD or below and were excluded. In all, 30 elderly individuals (25 females) were included, with 21 in the SCD group. For the whole sample, mean age and schooling were 70.83 (± 5.85) and 12.38 (± 3.98) years, respectively, with no significant differences between the groups. The CFI score was higher in the SCD group (SCD 4.38 ± 2.88 vs HC 0.72 ± 0.87, p < 0.001). The SCD group had more anxiety symptoms (p = 0.005). No differences were found between groups in the MMSE (SCD 29.00 ± 0.949 vs HC 29.33 ± 0.71, p = 0.449) and MoCA (SCD 23.76 ± 2.34 vs HC 24.22 ± 23.11, p = 0.659). There were also no significant differences in specific cognitive tests. Only the STMB differentiated SCD (11.00 ± 1.90) from HC (13.33 ± 1.56; p =0.004). Conclusions The STMB was the most sensitive to differentiate SCD from HC in this sample. Alzheimer disease neuroimaging biomarkers will be used to assess participants in future phases of the study.