Introduction
In this report we are describing a progressive brain disease featured by supranuclear ophthalmoplegia affecting chiefly vertical gaze, pseudobulbar palsy, dysarthria, dystonic rigidity of the neck and upper trunk, and other less constant cerebellar and pyramidal symptoms. Dementia has usually remained mild. This disease would appear to be predominantly a nerve cell degeneration centered chiefly in the brain stem.The fully developed clinical picture presented by this disease seems to follow a fairly definitive pattern and does not conform to the classical system degenerations such as motor neurone disease, paralysis agitans, cerebellar degeneration, Creuzfeldt-Jakob disease, or the presenile dementias. Yet it would seem unlikely that the disease shown by our cases is a new one, and similar earlier cases may well have been accepted as arteriosclerotic parkinsonism when that diagnosis was used in a very broad sense such as in Critchley's monograph of 1929.1 There are some resemblances to