Dissociation of Two Verbal Memory Tasks in a Brain Injured Sample: List Learning Versus Paragraph Memory.
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文摘
The present study was undertaken to assess the relative sensitivities of a serial list learning task (Rey AVLT) and a prose memory task (WMS Logical Memory subtest) for detecting impaired verbal short term memory performance in patients with traumatic brain injuries (TBI). Patients were 67 consecutive clinical referrals who were administered the AVLT and LM tasks as part of a comprehensive neurobehavioral examination following TBI. The majority of the patients were clearly classifiable as mild (LOC + PTA ≤ 1 h,n = 21) or severe (LOC + PTA ≥ 100 h, n = 39) TBI. To facilitate comparisons, all memory measures were converted to standard scores using published norms (Geffen et al., 1990; Osborne et al., 1973). Principal findings were as follows: (a) Although both the AVLT and LM are purported to measure verbal memory functioning, the measures correlated only r = .43 for the total sample. In paired comparisons, the mean AVLT total recall score was 1.3 standard deviations below LM (LM M = 94.05 vs. AVLT M = 74.87,p < .0005). (b) Within the sample as a whole, 60 % () of patients failed the AVLT, whereas only 22 % () failed the LM task. Failure was defined as performance below the 10th percentile of established norms. Ratings of impairment for the two tasks were concordant in only 18 % of the cases. (c) Mean LM scores in the mild and severe TBI groups were significantly different, but both were in the average range (Mild M = 98.9, Severe M = 92.0). In contrast, AVLT performance appeared to be much more sensitive to injury severity; mild TBI patients scored near the lower limit of the average range (M = 90.6), but the severe TBI group was grossly impaired (M = 67.0). The present findings suggest that clinicians should not rely solely on measures of prose memory in evaluating the mnemonic functioning of TBI patients, nor should they expect these measures to be interchangeable. List learning tasks, such as the AVLT used in the present study, would appear to be significantly more sensitive to verbal memory deficits in TBI patients, and seem to reflect injury severity.