Late progression of post-encephalitic Parkinson's syndrome.

We have studied 11 patients with neurological deficits due to the pandemic of encephalitis lethargica, all of whom had remained in hospital for more than forty years. Retrospective information obtained from physicians and nurses dating back as far as 1931, our own Webster and Northwestern University Disability Rating Scales available from 1976, photographic records, published narrative and hospital charts all indicate that neurological disabilities attributable to basal ganglia damage frequently increase in late life. Deterioration was most marked in motor function and largely spared the intellect, special senses and somatosensory system. The findings are discussed in relation to current hypotheses concerning the aetiology of Parkinson's disease.