The objective of this CIDA research is to specify the relations between the orofacial muscle deinnervation associated with amyotrophic lateral sclerosis (ALS) and the consequent functional disabilities that occur in speech and swallowing. While the speech and swallowing symptoms associtated with ALS have been described, almost no studies have provided data to address extant hypotheses concerning: (1) the relative severity of the ALS degeneration process in the different cranial motor nerves, or (2) the critical relations among the electromyographic, histochemical strength, speech, and swallowing aberrations that are associated with that motoneuron degeneration. Using five independent measures, data will be obtained longitudinally on a carefully selected population of 30 ALS patients and cross sectionally on a normal control group. The first data set will highlight speech motor functions, including anlyses of the speech acoutstic signal, judgements of dysarthric severity, and measures of lip, jaw and tongue movements. Secondly, videofluoroscopic analyses will be conducted on swallowing functions. The third data set will be obtained via instrumental measurement of weakness in the lip, jaw, tongue, and wrist flexor muscle groups, while the fourth set of measures will include quantitative EMG indices of single motor unit changes typically associated with ALS in several critical muscles of the tongue, jaw, lips, and forearm. Finally, as postmortem muscle tissue becomes available from the ALS subjects, a fifth set of data will include the morphology and histochemistry of the above mentioned muscles. These data will be analyzed to reveal critical causal relations between the orofacial neuromuscular pathophysiology associated with ALS and consequent problems in speech and swallowing.
