Neurologic signs in Alzheimer's disease. Results of a prospective clinical and neuropathologic study
H. Forstl, A. Burns, R. Levy, N. Cairns, P. Luthert and P. Lantos
Section of Old Age Psychiatry, Institute of Psychiatry, London, England.
Neurologic signs and their neuropathologic correlates were examined in a
sample of 56 patients with autopsy-proved Alzheimer's disease (13 men, 43
women; mean age at death, 83.1 years; range, 67 to 96 years) from a
prospective longitudinal study. Full-range regular rigidity with
cog-wheeling was found in 20 patients and was significantly associated with
lower neuron counts in the substantia nigra and with the presence of Lewy
bodies in the brain stem and neocortex. Twelve patients with myoclonus had
a younger age at onset, a lower age at death (mean, 78.6 years), and lower
neuron counts in the serotoninergic dorsal raphe nucleus and in the
noradrenergic locus coeruleus than did the patients without myoclonus.
Generalized motor seizures were reported in six patients, and they had
significantly lower counts of pyramidal cells in cortical layers III
through IV of the parietal cortex (area 7) and slightly decreased pyramidal
cell numbers in the parahippocampal gyrus (area 28). The 19 patients with a
positive grasp reflex had an earlier onset of illness and a significantly
inferior performance on the Mini-Mental State examination and Cambridge
Cognitive Examination tests. They, and 25 patients with a positive snout
reflex, had significantly lower counts of large pyramidal cells in layers
III through V of the frontal cortex (area 32). These results indicate that
different neurologic symptoms in Alzheimer's disease can be related to
disproportionate neuronal degeneration in functionally different brain
areas.
