| Research Abstract |
<1>Cervical spondylosis (CS) that can repeatedly insult the cervical cord has been one of the prime suspects of ALS etiology. Neuropathological features that CS itself brings about in the cervical cord, however, are not well differentiated from those of ALS because of rare autopsied cases with such double insults. To clarify the role of CS in pathogenesis of ALS, it is essential to differentiate the CS-from AIS-caused pathology. Then, we examined minutely the neuropathology of the cervical cord in ALS with marked cord compression at a single intervetebral level. The anterior horn was uniformly depleted of the motoneurons through the cervical cord. At the compressed level, the anterior horn neuropil was much more rarefied accompanying denser proliferation of microglia and less reaction of astrocytes, indicating that the spondylotic cord injuries may mainly involve the neuropil with suppression of astrocytic reaction and enhancement of microglial proliferation. <2>Although some patients with ALS show a particular type of dementia, the responsible neuropathology remains to be clarified because the autopsy often fails to show brain pathology that explains it. We performed ^<123>I-IMP-SPECT in 5 cases of ALS with dementia (ALSD), and analyzed the data using 3D-SSP with Z-score. This method revealed obvious reduction of cortical blood flow in the frontal and temporal lobes in ALSD. Neuropathological examination of one autopsied case which died soon after a ^<123>I-IMP-SPECT demonstrated spongy changes of the neuropil and irregular loss of neurons in the 2^<nd> and 3^<rd> cortical layers with marked astrocytosis in the subcortical white matter of the frontal lobe and medial side of temporal tip cortices. The blood flow reduction seen in the cerebral cortex in this condition is supposed to mainly reflect the neuronal loss and neuropil rarefaction in the superficial cerebral cortex.
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