Search

A brief paper-and-pencil instrument was developed to rapidly assess visuospatial ability and serve as an alterative to the WAIS Block Design subtests during screening or when assessment time is limited. The Design Organization Test (DOT) consists of square black-and-white grids with visual patterns similar to those of the Block Design subtests. Administration is straightforward and requires examinees to reproduce as many designs as possible in 2 minutes using a numerical code key. For 411 college students, alternate forms of the DOT yielded reliability estimates comparable to that of the test-retest reliability of WAIS-III Block Design subtest. In a clinical sample, the DOT was significantly correlated (r = .92) with WAIS-III Block Design scores and was successfully substituted in place of Block Design raw scores without significant change in Performance IQ or Full Scale IQ. The results suggest that the DOT provides a useful and rapid screening measure of visuospatial ability.

Recent neuroimaging studies suggest that episodic memory encoding involves a network of neocortical structures which may act interdependently with medial temporal lobe (mTL) structures to promote the formation of durable memories, and that activation in certain structures is modulated according to task performance. Functional magnetic resonance imaging (fMRI) was used to determine the neural structures recruited during a verbal episodic encoding task and to examine the relationship between activation during encoding and subsequent recognition memory performance across subjects. Our results show performance-correlated activation during encoding both in neocortical and medial temporal structures. Neocortical activations associated with later successful and unsuccessful recognition memory were found to differ not only in magnitude, but also in hemispheric laterality. These performance-related hemispheric effects, which have not been previously reported, may correspond to between-subject differences in encoding strategy., (Copyright 2002 Elsevier Science (USA).)

The authors report the findings of multimodal structural, functional, and metabolic imaging in a patient with linear nevus sebaceous syndrome, intractable seizures, and right megalencephaly. Despite nearly continuous paroxysmal electrical activity from the megalencephalic region, imaging studies suggested nonfunctional tissue in this region with reorganization of cortical function to the unaffected ipsilateral hemisphere. Hemispherectomy has been successfully performed in previous patients; however, it could have led to marked left hemiparesis with significant functional morbidity in this patient because of ipsilateral reorganization of the primary motor cortex.

The human hippocampus is critical to episodic encoding, but the role of the amygdala in memory is less clear. Animal research suggests a role for the amygdala in associative memory, but this has not been examined systematically in humans. Using fMRI, we compared amygdala and hippocampus activation for seven healthy subjects during two visual encoding tasks: serially presented single faces and faces presented as pairs. Single faces activated bilateral hippocampi, but not the amygdala. Paired faces activated bilateral amygdala, but only the left hippocampus. Subtraction of the two conditions revealed greater activation within the left amygdala and hippocampus during paired face encoding, suggesting that associative encoding activates a left-lateralized limbic network including the hippocampus and amygdala.

Cerebral hemispheric lateralization and personality traits were evaluated in 154 undergraduate and nonclinical volunteers. Personality ratings did not differ significantly between groups defined on the basis of hand, eye, or ear preference.

Prediction of post-surgical seizure relief and potential cognitive deficits secondary to anterior temporal lobectomy (ATL) are important to pre-surgical planning. Although the intracarotid amobarbital test (IAT) is predictive of post-ATL seizure outcome, development of non-invasive and more precise means for determining post-ATL seizure relief are needed. We previously reported on a technique utilizing functional MRI (fMRI) to evaluate the relative functional adequacy of mesial temporal lobe structures in preparation for ATL. In the present study, we report follow-up outcome data on eight temporal lobe epilepsy (TLE) patients 1-year post-ATL who were evaluated pre-surgically using IAT and fMRI. Functional memory lateralization using fMRI predicted post-ATL seizure outcome as effectively as the IAT. In general, asymmetry of functional mTL activation favouring the non-epileptic hemisphere was associated with seizure-free status at 1-year follow-up. Moreover, when combined, fMRI and IAT provided complementary data that resulted in improved prediction of post-operative seizure control compared with either procedure alone., (Copyright 1999 BEA Trading Ltd.)