The older adult (65 years or older) population is growing. The probability of developing cognitive impairment increases as adults pass the age of 65 years old. Cognitive reserve theory proposed factors that influence the expression of cognitive impairment. The lifestyle factors, namely: (a) education, (b) occupation, (c) social, (d) physical, and (e) leisure activities, influence cognitive reserve, which may affect how older adults express existence of cognitive impairment. Studies on cognitive reserve however, lack a standardized instrument to measure its constructs. In assessing the construct of lifestyle factors in a lifetime perspective, the Lifetime Experience Questionnaire (LEQ) is the only known instrument available. Therefore, to advance the cognitive reserve theory, an evaluation of the LEQ using different populations is essential. The study used a descriptive, test-retest, correlational design to examine the reliability and validity of the LEQ among older American adults (N=90) in North Carolina. Self-administered questionnaires including demographic data, the Geriatric Depression Scale-Short Form, the Mini-Mental State Exam (MMSE), and the LEQ were collected. A test and retest of the LEQ were conducted for 30 randomly selected participants. Test-retest reliabilities of the three subscales (r = .79 - .91), and the total LEQ score (r = .93) were acceptable. The Cronbach's alpha of the LEQ was .65. The association of the MMSE and LEQ that evaluated the concurrent validity of LEQ demonstrated minimal positive correlation (r = .19) that is not statistically significant with low effect size (.10). Although not statistically significant, the group that had low LEQ scores showed lower scores on the MMSE. The exploratory factor analysis supported the multidimensionality of LEQ. The LEQ had satisfactory temporal stability and interpretable construct validity; however, revisions of three items may be needed to increase its internal consistency. Quantifying lifestyle factors in a lifespan perspective is an immense beginning to operationally define the broad construct of cognitive reserve that may guide healthcare providers in individually planning interventions for maintenance or enhancement of older American adults' mental activities
