Estimating cognitive reserve in healthy adults using the Cognitive Reserve Scale

The concept of cognitive reserve emerged from observed disparities between brain pathology and clinical symptoms. It may explain better neuropsychological performance in healthy individuals. The objectives of this study were to measure reserve in healthy subjects using a new Cognitive Reserve Scale (CRS), analyze the internal consistency of the CRS, and analyze validity evidence. A total of 117 healthy individuals were divided into two groups: 87 adults (aged 18-64 years) and 30 elderly adults (≥65 years). All subjects completed the CRS and a comprehensive neuropsychological battery. The internal consistency of the scale was satisfactory (α = 0.77). No significant differences were observed between genders (t = 0.51, p = 0.611), and age was corrected by averaging the CRS score. The study of validity evidence showed that education affected the CRS (t = -2.98, p = 0.004, partial h2 = 0.07) and there was no significant relationship between the CRS and IQ (r = 0.09, p = 0.33). Occupational attainment and the CRS were not related (F2,116 = 0.11, p = 0.898). In line with previous studies on reserve, heterogeneity was observed in the analyses of relationships between the CRS and cognitive performance. There were significant relationships between CRS score and the Verbal Learning Spanish-Complutense Test last trial (r = 0.24, p = 0.009), sum (r = 0.32, p = 0.000), short-term (r = 0.29, p = 0.002) and long-term memory (r = 0.22, p = 0.018), Matrix Reasoning subtest (r = 0.20, p = 0.027) and Block Design subtest (r = 0.20, p = 0.029). No other neuropsychological variables correlated with the CRS (p>0.05). The CRS is a reliable instrument that reflects the frequency of participation in brain-stimulating activities across the lifetime. The associations between the CRS and education and neuropsychological performance support validity evidence.