Cognitive function tests (CFTs) were introduced in Visit 5 (1988) and included in each subsequent RBS clinic visit. The test battery assesses multiple cognitive domains vulnerable to effects of aging and critical for maintenance of independence, such as episodic memory and executive function. The specific tests administered at each visit are shown in here. The tests were selected in consultation with the Alzheimer’s Disease Research Center at the University of California, San Diego. The core tests, administered at every visit, include a subset of the tests included in the NACC UDS, enabling direct comparison of results with the NACC database and other large cohort studies. All CFTs in RBS were administered by trained, certified personnel, with consistent administration and scoring across visits.
RBS Core Cognitive Function Battery, administered at all 8 visits includes:
The Mini Mental State Exam (MMSE) uses 11 questions to assess orientation, registration, attention, calculation, language, and recall. Total MMSE scores range from 0 to 30. At visit 8, the MMSE was replaced by the Modified MMSE (3MS), an expanded version of the MMSE which assesses a wider range of cognitive abilities, with an expanded range of scores (0 to 100) to provide a more sensitive and reliable measure of global function than the MMSE. The 3MS was designed to enable derivation of the MMSE score, enabling direct comparison of results on the MMSE at all time points. Trail-Making Test Part B (Trails B) from the Halstead-Reitan Neuropsychological Test Battery is a sensitive measure of executive function, in which participants are required to connect, in ascending order, an alternating series of letters and numbers. Scores reflect time to complete the test, with a maximum of 300 seconds allowed. Category Fluency test of semantic ability asks participants to name as many animals as possible within one minute.
Additional tests administered at one or more visits, include:
The Buschke-Fuld Selective Reminding Test of verbal episodic memory, ten unrelated words are read to participants at a rate of one every two seconds. Immediately thereafter, the participant is asked to recall the entire list, and reminded of any words that were missed. The participant is asked to recall the entire list again. This procedure is followed for six trials. By examining the number and consistency of recall across trials, measures of short and long term storage are derived, as well as the total number of words recalled across all trials. This test was administered in five visits. The Heaton Visual Reproduction Test, adapted from the Wechsler Memory Scale test of visuospatial memory, participants are shown three cards containing increasingly complex geometric figures. Each card is shown for 10 seconds, and the participant is asked to reproduce the figures immediately and after a 30-minute delay. Participants are then asked to copy each figure to enable control for visuospatial impairments. This test was administered in four visits. The American National Adult Reading Test (AMNART) provides an estimate of intelligence. Participants read aloud a list of 50 irregular words. This test was administered in two visits. The CERAD Word List, the 10-item word list memory test from the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) was administered in two visits. Two items from the Blessed Information-Memory- Concentration Test (Blessed Items) that assess executive function and episodic memory were administered Participants were asked to name the months of the year backward, and to recall a five-part name and address following a 10-minute delay. These items were administered in two visits. Logical Memory IA and IIA from The Wechsler Logical Memory-Revised is a test of verbal episodic memory in which participants are read a short paragraph and asked to recall as much of the story as possible immediately and after a 20-min delay. The Modified Pfeffer Functional Activities Questionnaire (FAQ) is a survey of functional ability where the participant or an informant answer questions about ten instrumental activities of daily living, such as ability to balance a check book or shop independently. The FAQ, which is also part of the NACC UDS, was administered at five visits.