Degeneration of the brain stem reticular formation, other parts of the brain stem and the cerebellum; an example of heterogenous systemic degeneration of the central nervous system.

Degenerative diseases of the central nervous system have until recently been considered as being rather fixed in type, and most cases could be readily classified. The outstanding degenerative diseases are: Amyotrophic Lateral Sclerosis, Spinal Muscular Atrophy, and Friedreich's Tabes in the spinal cord. In the encephalon they are: Atrophy of either basal ganglia or the cerebellum, together with a number of nuclei and fiber systems related to them. While in some cases a whole system is changed, in others only parts of a certain system are involved. Transitional cases in which parts of more than one of the systems are affected apparently were rarely seen, and for a long time degenerative diseases restricted to one system only have been considered the rule. These types of diseases were in most instances familiar and hereditary, and it was assumed that the cause was a defective anlage of the system involved. However, in the course of the last 25 years a number of transitional cases have been described, and it becomes more and more obvious that the "typical" forms have too soon been assumed to be invariable. Cases of combined systemic diseases described in the literature are: Five cases of olivo-ponto-cerebellar atrophy with atrophy of the substantia nigra and the striatum (Scherer (14)); Friedreich's tabes with 1. degeneration of the lenticular nucleus (Josephy, (9)); 2. with degeneration of the globus pallidus and the substantia nigra (Greenfield, (8)); and 3. with degeneration of the pyramidal tract, the basal pontine and dentate nuclei (Gerstmann, Straussler and Scheinker, (7)). Other combinations are: Degeneration of the basal pontine nuclei, the posterior funiculi, Clarke's columns, the cerebellar cortex, the dentate nucleus and of the substantia nigra (Waggoner, Lowenberg and Speicher (19)). Verhaart (15) l'eported the combined degeneration of spinal and brain stem muscular atrophy, Clarke's columns and Gower's tract, of the globus pallidus, the subthalamic body, the basal pontine nuclei, the superior colliculus, the dentate nucleus, and of the brain stem tegmentum. Van Bogaert (4) described the following combinations: pallido-nigral, combined either with olivo-pontine degeneration and degeneration of Goll's funiculus or with degeneration of the cerebellar cortex, the dentate and olivary nuclei, Goll's funiculus, the ventral spino-cerebellar tract and the papillo-macular bundle, or with a general cerebellar atrophy. Olivo-ponto-cerebellar atrophy was combined with degeneration of the substantia nigra (Lambie, Latham and McDonald (ll)). Van Bogaert (6) reported a combination of Hallervorden-Spatz disease with cerebello-dentate