Verbal and Non-Verbal Short-Term Memory Impairment Following Hemispheric Damage

Abstract

Short-term memory was investigated in 30 control and 125 unilaterally brain-damaged patients with a series of tests requiring the immediate reproduction of strings of items of increasing length. In three tests the items were auditorially presented digits or words: one test asked for oral repetition of digits, while the other two required the patient to point to written digits or to pictures. The fourth test aimed at measuring spatial span. On both the Digits Forward test and the two other verbal tests not requiring the use of speech, left brain-damaged patients were impaired in comparison to normals, while the right brain-damaged patients were not. Aphasics had a significantly shorter verbal span than non-aphasic patients with left hemisphere damage. Spatial span, on the other hand, was significantly affected by a lesion posteriorly located in either hemisphere, but not by aphasia. Two patients with an exceedingly poor verbal memory span were observed, one suffering from anomic aphasia and the other from conduction aphasia. There were also two right hemisphere damaged patients who showed an extreme reduction of spatial span, which could not be accounted for by space perceptual disorders and contrasted with a normal performance on a spatial long-term memory test.

Does lateral parietal cortex support episodic memory?

“…Activity in this region is strongly linked to rehearsal of information held in auditory or visual buffers, more so than to the executive components of working memory (for reviews, see Baddeley, 2003;D'Esposito et al, 2006;Martin, 2005;Smith & Jonides, 1998). Lesion studies are generally consistent with this finding (e.g., De Renzi & Nichelli, 1975;Markowitsch et al, 1999;Warrington & Shallice, 1969;Warrington et al, 1971; see also Butters et al, 1970;Samuels et al, 1971). Participants may engage in a greater degree of post-retrieval rehearsal than normal in the scanner due to the unusual demands inherent to the scanning situation.…”

A model linking immediate serial recall, the Hebb repetition effect and the learning of phonological word forms

“…Baddeley et al (1998) provided a comprehensive review, integrating data from a variety of sources. They brought together evidence from neuropsychological case studies of so-called 'short-term memory' patients (Warrington & Shallice 1969;de Renzi & Nichelli 1975;Basso et al 1982;Trojano & Grossi 1995 etc.). These patients had experienced, either developmentally or as a result of later insult, a form of brain damage that had drastically limited their auditory verbal span, in some cases to such an extent that they appeared to have no effective memory for the sequential aspects of unfamiliar auditorily presented lists.…”

The right parietal lobe is critical for visual working memory

“…In one commonly used task, the Corsi block task, participants point to a sequence of locations in the same order as that produced by the experimenter (Corsi, 1972;reviewed in Berch, Krikorian, & Huha, 1998). Although the Corsi block task has been heavily used in neuropsychology, most studies fail to adequately describe or localize the lesion, stating only that right hemisphere damage leads to impaired spatial recall (De Renzi et al, 1977;De Renzi & Nichelli, 1975;Hanley, Young, & Pearson, 1991). More recent studies with MRI-verified lesion locations have reported that either left (Baldo & Dronkers, 2006) or right (Malhotra et al, 2005) inferior parietal lobe damage can cause impaired Corsi block performance.…”