The morphological and morphometric estimation of the acoustic cortex revealed loss of Cajal-Retzius cells in layer I, as well as an impressive abbreviation of the dendritic fields associated with loss of dendritic spines in all layers of the cortex. Numerous distorted, dystrophic and degenerated dendritic spines were also seen, which were intermixed with a considerable number of giant spines. The dendritic and spinal alterations were closely associated with mitochondrial alterations.

The morphological and morphometric analysis revealed substantial neuronal loss and synaptic alterations in the medial geniculate bodies as well as in inferior colliculi. Dendritic spines of the polyhedral and elongated cells of the medial geniculate bodies were decreased in number. Mitochondrial alterations and fragmentation of Golgi apparatus were seen in 15% of the neurons of the medial geniculate bodies and in 5% of the neurons of the inferior colliculi. Senile plaques and neurofibrillary tangles were not seen in either the medial geniculate bodies or the inferior colliculi.

The morphological and morphometric estimation of the acoustic cortex revealed loss of Cajal-Retzius cells in layer I, as well as an impressive abbreviation of the dendritic fields associated with loss of dendritic spines in all the layers of the cortex. Numerous distorted, dystrophic, and degenerated dendritic spines were also seen, which were intermixed with a considerable number of giant spines. The dendritic and spinal alterations were closely associated with mitochondrial alterations.

The morphological and morphometric analysis revealed substantial neuronal loss and synaptic alterations in the acoustic cortex in all the cases of FTD and particularly in Pick disease and in primary progressive aphasia. Mitochondria alterations and changes of the Golgi apparatus were seen mostly in Pick disease.

Biopsy material from the vocal muscle of patients suffering from Steinert's muscular dystrophy, Duchenne's muscular dystrophy, oculopharyngeal progressive muscular dystrophy, and paraneoplastic myopathy was examined under the light and electron microscope. The histological findings were compatible with the muscular changes seen in the skeletal muscles of the extremities of the same patients. Slight differences in the severity of the pathologic process were noticed in correlation with the muscles of the extremities which were always more seriously affected than the vocal muscles. The ultrastructural study revealed a moderate to very permanent dilatation of the sarcotubular system, involving the T-tubules and the cisternae of the smooth endoplasmic reticulum as well. From the clinical point of view, the vocal muscle biopsy was beneficial to the patients suffering from Steinert's myotonic muscular dystrophy, whereas it did not affect the clinical condition of the others.