The psychological construct of word fluency.

Measures of word fluency have been convincingly linked in the literature to damage in the left prefrontal lobe region. Yet, a reduction in word fluency has also been reported with diffuse, multifocal and nonfrontal lobe damage. Despite the undisputed neuropsychological application of multiple word fluency measures, the psychological construct underlying this measure is not well understood. In a sample of 360 normal adults stratified by age, gender, and level of education, we found that auditory attention and word knowledge were among the most important determinants. With respect to memory, short-term memory was not significantly correlated, but long-term memory was. Despite these three determinants, a large share of the variance of the multiple regression was still not accounted for, which underscores the partial independence of word fluency per se. Thus, we propose a distinction between (1) poor word fluency secondary to deficient verbal attention, word knowledge, and/or verbal long-term memory and (2) impaired word fluency without these three areas concurrently affected. Based on a review of the literature, it seems likely that in the latter condition, the profile is more associated with prefrontal lobe impairment, versus in the former condition, diffuse multifocal or nonfrontal lobe factors can play a role.

Benton Controlled Oral Word Association Test: reliability and updated norms.

The aim of this paper is to update the over 20-year-old normative data for the Benton Controlled Word Association (COWA) Test. In a sample of 360 normal volunteers, the age ranged between 16-70 years, and the educational level ranged from 7-22 years. Care was taken to ensure that the population was heterogeneous, yet the two stratifications of gender, four age, and three educational groups led to 24 cells with 15 individuals in each. Test-retest reliability was established by testing 30% of the sample after a 6-month delay, which represents a typical follow up duration between testings in a clinical setting. The two forms of the COWA revealed significant test-retest reliability. Generally, our updated values fall above the original normative values, which were derived from a less well-educated and rural sample. No major gender or age trends were noted, but the COWA test performances were influenced by education, i.e., as the level of education increased, the performance on the COWA increased. The only gender differences that were found were for the women in the highest educational group ( > 16 years), who performed significantly better that men in the highest educational group. An error analysis of repetitions or perseverations is provided, with cut-off scores according to age levels. Finally, the updated COWA norms are compared to the original norms as well as to other measures of word fluency.

Selective Reminding Tests: a normative study of verbal learning in adults.

Verbal learning was assessed according to the Selective Reminding Test (SRT) in order to establish normative data and to provide a comparison with measures of immediate attention, verbal IQ, and verbal memory. The 392 subjects, stratified by sex (202 women, 190 men), age (4 groups: 16-70 years), and education (3 groups), were free of conflicting pathologies. Learning curves were established on centiles (75, 50, 25, 5). Sex differences favoring women were found in percent of finishers (those who reached criterion), and at all percentile levels of acquisition. Data were analyzed for group differences in performance on the SRT and related concurrent measures, but sex differences were not found on the VIQ or immediate attention tests. Also, assumptions of age and education stratification were not confirmed. However, those who completed the task were better able to form associational strategies than those who were unable to finish. The present data indicate that it is important to use detailed norms by gender and criterion level if clinical interpretations are to be valid.

Automatic detection vs controlled search: a paper-and-pencil approach.

A new measure of selective attention was presented to 259 normal volunteers. The test was derived from earlier work which emphasized the importance of controlling the distracting conditions using a selective-attention paradigm. In the present study a paper-and-pencil, digit-cancellation format was introduced and the data documented a significant dissociation between tasks analogous to controlled search and automatic detection, two theoretically important aspects of selective attention. Presented is a discussion of similarities and differences of the new measure and classical methods of discriminating between controlled search and automatic detection and the potential significance of this discrimination in clinical neuropsychological investigations.