The effects of dual tasking in Parkinson's disease (PD) have been studied for a number of years. Previous research has generally focused on changes in gait patterns while another task has been performed concurrently. Very few studies have focused on the impact of a concurrent task on speech or language. Language is key for communication: to express wants and needs, to maintain familial relationships, and for social interaction. Thirty-seven individuals participated in the study: 10 with PD, 14 neurologically healthy older (HO) adults, and 13 healthy younger (HY) adults. The participants were given a list of topics to consider and were invited to select several to talk about during the experiment. Their monologues were recorded as they spoke under three conditions: standing still, walking on a treadmill, and walking over randomly presented obstacles on a treadmill. The monologue recordings were transcribed, marked for processing by Systematic Analysis of Language Transcripts (SALT), and analyzed for subordinate clauses by a language expert. The language variables measured were the mean length of utterance in morphemes (MLUm), relative clauses per utterance, adverbial clauses per utterance, noun clauses per utterance, total clauses per utterance, words per minute, different words per minute, relative clauses per minute, adverbial clauses per minute, noun clauses per minute, total clauses per minutes, and utterances per minute. There were significant changes across the conditions of standing, walking, and obstacle in the language variables of words per minute, different words per minute, noun clauses per minute, total clauses per minute, and utterances per minute. A downward trend was noted for adverbial clauses per minute as the gait task became more demanding. The PD and HO groups had less complex language than the HY group, as reflected by the following language variables: adverbial clauses per minute, noun clauses per minute, and total clauses per minute. These findings suggest that as attentional resources used for the production of language are directed to increasing levels of motoric activity, language complexity will significantly decrease across conditions.



College and Department

David O. McKay School of Education; Communication Disorders



Date Submitted


Document Type





Parkinson's disease, dual tasking, language complexity, gait