Impaired Long-Term Retention Despite Normal Verbal Learning in Patients With Temporal Lobe Dysfunction

Long-term retention of verbal material was investigated in patients with unilateral temporal lobe (TL) dysfunction (n = 21) and tension headache controls (n = 21) who were matched on a pairwise basis for initial learning on the Selective Reminding Test. Free recall and recognition memory performances were assessed following 30-min and 24-hr delays. Patients with TL dysfunction recalled significantly fewer words at the 24-hr delay despite equivalent recall performance during the final learning trial and at the 30-min delay. No significant group differences were found for recognition memory performance across delay conditions. These data suggest that TL dysfunction contributes to impaired retention of verbal information over time despite normal learning ability. Inclusion of multiple delay measures may improve the likelihood of detecting subtle memory deficits in TL patients who demonstrate normal learning ability.