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M F O'Shea

Publications and source records attributed to M F O'Shea.

7 recordsLinked to original sources
PubMed2000

Components of verbal learning and hippocampal damage assessed by T2 relaxometry.

We studied a group of 31 temporal lobe epilepsy patients (25 left, 6 right) with unilateral hippocampal sclerosis evident on magnetic resonance imaging. Single slice T2 relaxation times were acquired for the left and right hippocampi. Principal components analysis of preoperative memory data resulted in two factors that reflect a distinction between arbitrary and semantic forms of verbal recall. The former component correlated with left hippocampal T2 relaxation time, while the latter component did not. This study suggests that variation in left hippocampal integrity is more related to the acquisition of arbitrary associates than semantically structured material, and reinforces the possibility that the left temporal lobe is functionally heterogeneous with respect to memory.

Adolescent↗
PubMed1999

Reorganization of verbal memory and language: a case of dissociation.

Left-to-right reorganization of verbal memory following early left hemisphere damage has been reported in patients whose expressive language is governed by the right hemisphere. We present a case in which verbal memory performance was intact, despite severe left mesial temporal damage, and despite aphasia on left internal carotid sodium amytal ablation. The distribution and degree of left mesial temporal damage was assessed visually and quantitatively on MRI. These findings raise the possibility that verbal memory may shift to the language-nondominant hemisphere as a result of early left mesial temporal damage.

Brain Damage, Chronic↗
PubMed1996

Does naming contribute to memory self-report in temporal lobe epilepsy?

The present study evaluated the hypothesis (Mayeux et al., 1980) that visual confrontation naming deficits may underlie the memory complaint in patients with temporal lobe epilepsy (TLE). Thirty-nine patients with medically refractory left (n = 23) and right (n = 16) TLE were compared with an epilepsy control group with idiopathic primary generalized epilepsy (n = 38). All subjects completed selected subtests of the Multilingual Aphasia Examination and Wechsler Memory Scale (Form 1) together with a measure specifically designed for quantification of the memory complaint in TLE. Objective verbal memory test performance, confrontation naming, repetition, and comprehension were unrelated to memory self-report. Controlled Oral Word Association was the only measure to exert an influence on memory self-ratings, and this relationship was specific to the TLE group. The hypothesis of Mayeux et al. (1980) was not specifically supported, but the present findings do suggest that cognitive processes reflected in orthographically based and internally generated word retrieval play a role in memory self-report.

Adult↗
PubMed1994

Can metamemory be localized?

This comment examines current neuropsychological literature in the field of metamemory. One notion emerging from this literature is that metamemory is mediated by the frontal lobes. We argue that this idea is the result of inadequate conceptual approaches to metamemory and that currently there is no evidence to support the cerebral localization of metamemory.

Brain Damage, Chronic↗
PubMed1994

Rey figure distortions reflect nonverbal recall differences between right and left foci in unilateral temporal lobe epilepsy.

Recall of the Rey Complex Figure (RCF) by patients with left (N = 26) or right (N = 18) temporal lobe epilepsy was scored in terms of the qualitative approach developed by Loring, Lee, and Meador. Patients with right temporal lobe epilepsy exhibited significantly more qualitative errors on recall of the RCF than patients with left temporal foci, whereas standard RCF scores failed to differentiate the groups. A linear discriminant function analysis showed that 66% of patients were correctly classified into lateral focus groups on the basis of qualitative scores, with a sensitivity of 50% and specificity of 77%. Although unsuitable for clinical use in its present form, the qualitative approach appears to be a promising one. The findings offer support for the position that some aspects of nonverbal memory are critically dependent on the integrity of the right temporal lobe. The implications of this for reorganization of cerebral representation are examined.

Journal Article↗
PubMed1993

Lateralization of verbal memory and unilateral hippocampal sclerosis: evidence of task-specific effects.

This study retrospectively investigated the effect of left (LHS) versus right (RHS) hippocampal sclerosis on verbal memory, measured by means of the Paired Associate Learning and Logical Memory subtests of the Wechsler Memory Scale (WMS) administered as part of a routine preoperative assessment. Patients were selected for the presence of unilateral hippocampal sclerosis by means of preoperative magnetic resonance imaging (MRI) and postoperative neuropathology. The LHS patients (n = 20) were significantly worse on paired associate learning than RHS patients (n = 18), the performance of RHS patients being consistent with normative standards. In contrast, no laterality effect was seen on the immediate and delayed recall of passages; the evidence suggests that both groups performed at a mildly impaired level. It was suggested that the laterality of verbal memory is conditional upon specific task demands in patients with damage to mesial temporal structures.

Adult↗