Spinal deformities have been evaluated in a five year retrospective study where 28 boys and 25 girls all having Friedreich's ataxia were on the average assessed once a year in a multidisciplinary clinic. Scoliosis seems somewhat more progressive in girls than in boys and more severe in non-ambulatory than ambulatory patients. Some of those scolioses are very progressive reaching 60° to 100° Cobb angle values requiring spinal surgery while other progress less rapidly and do well on their own. In addition it was shown that the intrinsic geometric spine curve parameters namely that of curvature and torsion are a powerful diagnostic tool in the assessment of evolutive scoliosis.

l-Methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) selectively destroys dopaminergic neurons in the pars compacta of the substantia nigra (A8 and A9 cells). MPTP or its metabolite enters nerve cells at the level of their terminals in the caudate nucleus and putamen leading to a disturbance in axoplasmic flow and retrograde degeneration. The species-dependent neurotoxicity of MPTP (primate vs. rodent) suggests that a biochemical property of the cell related to neuromelanin may be important in the mechanism of cell injury.

Myocardial scanning after the intravenous administration of Thallium 201 was used to evaluate regional myocardial perfusion in 14 patients with Friedreich's ataxia. Isotopic ventriculography was also used to assess left ventricular contractility. Myocardial images in patients with Friedreich's ataxia were found to be precociously abnormal irrespective of the degree of neurological impairment or of the severity of myocardial hypertrophy.

Local cerebral glucose utilization was measured in patients with predominantly unilateral Parkinson’s disease using 18F-2-fluoro-deoxyglucose and positron emission tomography. Preliminary results indicate the presence of asymmetric metabolic rates in the inferior basal ganglia. The structure comprising the largest portion of basal ganglia at this level is globus pallidus. These findings are consistent with metabolic studies on animals with unilateral nigrostriatal lesions in which pallidal hypermetabolism on the lesioned side has been demonstrated. Increased pallidal activity is likely secondary to a loss of inhibitory dopaminergic input to the striatum from substantia nigra.

[18F] 6-fluoro-L-dopa and positron emission tomography has been used to study intracerebral dopamine distribution in five control subjects and six patients with hemiparkinsonism. In the control subjects striatal, frontal and cingulate accumulations were clearly seen. In addition 18F concentrated in the region of the insula and the parietal lobe.

In the patients striatal accumulation 18F was reduced in the contralateral striatum, especially in the putamen. The uniformity of distribution of 18F in the striatum on the side of the parkinsonian signs was also irregular. This finding is consonant with the suggestion that intracerebral compensatory mechanisms prevent the manifestation of intracerebral dopamine deficiency from becoming obvious until a late stage of the disease.

We present the pathological data from the autopsies performed on 6 Friedreich's disease patients since the start of the Quebec Cooperative Study. All patients met the strict diagnostic criteria of the QCSFA. The anatomical lesions found in the peripheral and central nervous system were similar in all 6 cases and do not differ from those described in the literature. The clinical findings correlate closely with the histological lesions found in the peripheral nervous system and spinal cord. The evidence of segmental demyelination and remyelination in the spinal ganglia and posterior roots further supports the dying-back axonopathy hypothesis.

The literature pertinent to the pathological anatomy subserving dementia in Parkinsonian patients is reviewed. Mechanisms discussed include cerebral cortical atrophy; hydrocephalus; Lewy body inclusions; neocortical lesions of the Alzheimer type; depletion of cholinergic, dopaminergic or noradrenergic transmitter systems; ‘subcortical’ dementia; and neuronal depopulation of the basal forebrain.

New autopsy data are presented to confirm that, contrary to published reports, most patients with parkinsonism who exhibit dementia do not have concomitant Alzheimer’s disease, and that some different pathogenetic mechanism must be sought to account for this increasingly common cause of cognitive decline in the sufferers of Parkinson’s disease.