Interhemispheric disconnection syndrome in Alzheimer's disease.

It is commonly acknowledged that patients with Alzheimer's disease show memory and cognitive deficits that result from their cerebral histopathological abnormalities. We report new evidence showing that they also manifest deficits in interhemispheric integration of information, probably reflecting a corpus callosum dysfunction. Patients were given a battery of motor, somatosensory, and visual tests that had to be carried out by using either one or both hemispheres. Tasks were chosen such that subjects with Alzheimer's disease performed normally when using intrahemispheric processing. They, however, performed poorly when interhemispheric communication was required. This observation attests to the presence of a disconnection syndrome and suggests that these interhemispheric tasks can serve as diagnostic tools for the early assessment of their dementia.

[1]  R. Nicoletti,et al.  Is interhemispheric transfer of visuomotor information asymmetric? Evidence from a meta-analysis , 1991, Neuropsychologia.

[2]  P. Lantos,et al.  β-Amyloid protein load is relatively uniform throughout neocortex and hippocampus in elderly Alzheimer's disease patients , 1991, Neuroscience Letters.

[3]  B. Reisberg,et al.  The Global Deterioration Scale for assessment of primary degenerative dementia. , 1982, The American journal of psychiatry.

[4]  M. Lassonde,et al.  Absence of disconnexion syndrome in callosal agenesis and early callosotomy: Brain reorganization or lack of structural specificity during ontogeny? , 1991, Neuropsychologia.

[5]  G Rizzolatti,et al.  Simple reaction times of ipsilateral and contralateral hand to lateralized visual stimuli. , 1971, Brain : a journal of neurology.

[6]  G K Wilcock,et al.  Anatomical correlates of the distribution of the pathological changes in the neocortex in Alzheimer disease. , 1985, Proceedings of the National Academy of Sciences of the United States of America.

[7]  A. Brun,et al.  Regional pattern of degeneration in Alzheimer's disease: neuronal loss and histopathological grading , 1981, Histopathology.

[8]  P. Moes,et al.  Interhemispheric transfer time differences related to aging and gender , 1996, Neuropsychologia.

[9]  M Moscovitch,et al.  Memory as assessed by recognition and reading time in normal and memory-impaired people with Alzheimer's disease and other neurological disorders. , 1986, Journal of experimental psychology. General.

[10]  N. Geschwind.  Disconnexion syndromes in animals and man. I. , 1965, Brain : a journal of neurology.

[11]  Gillian Cohen,et al.  Hemispheric differences in a letter classification task , 1972 .

[12]  M. Moscovitch,et al.  Intermanual information transfer in patients with lesions in the trunk of the corpus callosum , 1984, Neuropsychologia.

[13]  A. Baddeley,et al.  Autobiographical memory and executive function in early dementia of Alzheimer type , 1995, Neuropsychologia.

[14]  G. Geffen,et al.  The effect of lesions of the corpus callosum on finger localization , 1985, Neuropsychologia.

[15]  M. Gazzaniga.  The Bisected Brain , 1970 .

[16]  M. Apuzzo,et al.  Transcallosal, interfornicial approaches for lesions affecting the third ventricle: surgical considerations and consequences. , 1982, Neurosurgery.

[17]  G. Fisher,et al.  Free D-aspartate and D-alanine in normal and Alzheimer brain , 1991, Brain Research Bulletin.

[18]  S. Bellur.  Alzheimer's Disease: Senile Dementia and Related Disorders , 1979 .

[19]  K. Shoumura,et al.  Structural organization of ‘callosal’ OBg in human corpus callosum agenesis , 1975, Brain Research.

[20]  J. Morris,et al.  Validation of clinical diagnostic criteria for Alzheimer's disease , 1988, Annals of neurology.

[21]  Suzanne Corkin,et al.  Visual dysfunction in Alzheimer's disease: Relation to normal aging , 1991, Annals of neurology.

[22]  M. Albert,et al.  Neurobiological Bases of Age-Related Cognitive Decline in the Rhesus Monkey , 1996, Journal of neuropathology and experimental neurology.

[23]  B. Preilowski,et al.  Possible contribution of the anterior forebrain commissures to bilateral motor coordination. , 1972, Neuropsychologia.

[24]  S. Folstein,et al.  "Mini-mental state". A practical method for grading the cognitive state of patients for the clinician. , 1975, Journal of psychiatric research.

[25]  Extent and limits of cerebral adjustment to early section or congenital absence of the corpus callosum , 1988, Behavioural Brain Research.

[26]  T. Powell,et al.  An electron microscopic study of the laminar pattern and mode of termination of afferent fibre pathways in the somatic sensory cortex of the cat. , 1970, Philosophical transactions of the Royal Society of London. Series B, Biological sciences.

[27]  M J Campbell,et al.  Laminar and regional distributions of neurofibrillary tangles and neuritic plaques in Alzheimer's disease: a quantitative study of visual and auditory cortices , 1987, The Journal of neuroscience : the official journal of the Society for Neuroscience.