Memory and encoding of spoken discourse following right hemisphere damage:Evidence from the Auditory Moving Window (AMW) technique

We investigated the hypotheses that impaired discourse processing following right hemisphere damage is mediated by task difficulty and is associated w ith deficits in discourse encoding. Spoken discourse passages differing in contextual predictability were presented to right hemisphere-damaged (RHD) patients and to non-brain-damaged (NBD) controls for subsequent recall usin g the Auditory Moving Window paradigm. To manipulate processing difficulty, speech segments were of normal or accelerated speech rates. The recall res ults showed that RHD adults recalled less than NBD controls overall and fai led to recall major idea units better than minor idea units for high predic tability passages presented at accelerated speech rates. Both RHD patients and NBD controls failed to recall major idea units better than minor idea u nits for low predictability passages, regardless of speech rate. The encodi ng results showed that RHD adults were both slower overall and differential ly slower than NBD controls when listening to accelerated passage segments. Taken together, the encoding and recall results are consistent with the vi ew that extracting passage gist under difficult listening conditions is esp ecially vulnerable for patients with right hemisphere strokes. (C) 2001 Aca demic Press.