Four-hour delayed memory recall for stories: Theoretical and clinical implications of measuring accelerated long-term forgetting.
It has been noted that clinical neuropsychological assessment is "blind" to certain abnormalities of consolidation that occur beyond standard 30-min delay intervals. For example, normal forgetting at 30-min delays has been followed by enhanced forgetting at longer delays in temporal-lobe epilepsy, termed accelerated long-term forgetting (ALF). To evaluate whether ALF could be identified in the neuropsychological assessment of a small sample of examinees with head injuries or other neurological diagnoses (n = 42), a 4-hr delayed recall condition was added to the Logical Memory subtest of the Wechsler Memory Scale-Third Edition. A small percentage of examinees (5/42 or 11%), despite exhibiting unimpaired story recall immediately and after 30-min delays, showed increased forgetting when compared with the average retention of stories (M = 0.83, SD = 0.17) after a 4-hr delay. Three of these 5 examinees also had impaired scores on 20-min delayed recall of the California Verbal Learning Test-Second Edition (CVLT-II) and would have been identified as having memory impairment without an extended, 4-hr delayed recall. In fact, the highest correlation among memory indexes was between 4-hr delayed recall of stories and delayed recall of the CVLT-II word list (r = .59, p < .0001), suggesting different consolidation rates for relational and nonrelational material.
a Private Practice , Toronto , Ontario , Canada.
Ricki L
RL
Ladowsky-Brooks
D000328:Adult; D000368:Aged; D000070642:Brain Injuries, Traumatic / Q000150:complications; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis* / Q000209:etiology; D011939:Mental Recall / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D012153:Retention, Psychology / Q000502:physiology; D013223:Statistics as Topic; D013997:Time Factors; D014706:Verbal Learning / Q000502:physiology; D055815:Young Adult
Accelerated long-term forgetting; consolidation; hippocampus; logical memory; temporal lobe