Extending the Administration Time of the Letter Fluency Test Increases Sensitivity to Cognitive Status in Aging

Abstract

The authors examined whether extending the administration time of letter fluency from 1 minute per letter trial (standard administration) to 2 minutes increased the sensitivity of this test to cognitive status in aging. Participants (mean age = 84.6) were assigned to cognitive impairment (n = 20) and control (n = 40) groups. Pearson correlations and scatter plot analyses showed that associations between the Dementia Rating Scale scores and letter fluency were higher and less variable when performance on the latter was extended to 2 minutes. Analysis of variance (ANOVA) showed that the cognitive impairment group generated fewer words in the second minute of the letter fluency task compared to the control group. Finally, discriminant function analyses revealed that extending the letter fluency trials to 2 minutes increased discrimination between the control and cognitive impairment groups.

Roee Holtzer is supported by a Paul B. Beeson Award (NIA-K23 AG030857).

Notes

∗p ≤ .05; ∗∗p ≤ .01.

DRS = Dementia Rating Scale; LF = letter fluency; LF 1 minute = total number of words generated in the first minute of administration; LF 2 minutes = total number of words generated in 2 minutes of administration; I/P = initiation/perseveration. Independent-samples t tests (df = 58) were used to examine group differences on all continuous measures. Chi-square analysis was used to examine group differences in gender distribution.

∗p ≤ .05; ∗∗p ≤ .01.

DRS = Dementia Rating Scale; LF = letter fluency; LF 1 minute = total number of words generated in the first minute of administration; LF 2 minutes = total number of words generated in 2 minutes of administration; LF difference = difference between number of words generated in 1 versus 2 minutes of administration; I/P = initiation/perseveration.

¹Analyses adjusting for age and gender as well were not materially different.