Distinguishing Spastic and Dystonic Features in a Patient With a History of Brainstem Encephalitis: A Clinical Case Study

Abstract

Purpose One role of a speech-language pathologist (SLP) is to differentially diagnose motor speech disorders to aid physicians, typically neurologists, in establishing a medical diagnosis. The present case study describes the clinical problem solving undertaken by the SLP to characterize the nature of neurological deficits to develop an appropriate management plan. Method The patient is a 29-year-old man with a history of brainstem encephalitis who presented for evaluation of dysarthria, dysphagia, and gait difficulties. The neurological exam characterized a spastic dysarthria. The SLP conducted a motor speech examination expressly for the purpose of differential diagnosis. Results The patient exhibited features of spastic dysarthria including strained phonation and hypernasality, equivocally slow rate associated with intermittent interword pauses rather than lengthened segments, and articulatory imprecision in the absence of weakness or slowness of the articulators. Defining features of spastic dysarthria absent from his speech were monopitch and monoloudness, as well as slow alternate motion rates. A diagnosis of hyperkinetic dysarthria associated with dystonia was informed by (a) hypernasality disproportionate to other deviant speech features, with preserved reflexive velar movements and nonspeech movements; (b) adventitious lip pursing; (c) modest improvement in speech with sensory tricks; (d) mild and intermittent phonatory strain; and (e) normal nonspeech oral motor function. Conclusions This case demonstrates the role speech-language pathology can play in the neurological assessment and management process. The recognition by the SLP of hyperkinetic dysarthria led to additional diagnostic tests and to a broader range of options for medical management.