Harry Lee Parker and paroxysmal dysarthria and ataxia

Objective: To review descriptions of paroxysmal dysarthria and ataxia in multiple sclerosis (MS), with special attention given to Parker and his 1946 case series. Methods: Evaluation of original publications describing paroxysmal dysarthria and ataxia, bibliographic information, writings, and unpublished letters from the Mayo Clinic Historical Unit. Results: In 1940, Störring described a patient with MS with paroxysmal symptoms that included dizziness and trouble speaking, but also unilateral extremity weakness. In 1946, Parker published a series of 11 patients with paroxysmal dysarthria and ataxia. Six of these patients had MS, and he recognized this phenomenon as a manifestation of the disease. The term "paroxysmal dysarthria and ataxia" was first used in 1959 by Andermann and colleagues. Since that time, paroxysmal dysarthria and ataxia has become a well-recognized phenomenon in MS. More recent reports have suggested that the responsible lesion is located in the midbrain, near or involving the red nucleus. Conclusions: Parker was the first to accurately describe paroxysmal dysarthria and ataxia in patients with MS.