Changes in temporal features of speech in secondary progressive multiple sclerosis (SPMS) - case studies

Multiple sclerosis (MS) is a chronic inflammatory disease which, in addition to affecting motor and cognitive functions, may involve language disorders. Despite the importance of speech and language disorders in the quality of life of patients, there are only a few studies about language and speech production difficulties in MS. The aim of this research is to describe the limitation patterns of speech and temporal characteristics of the suprasegmental level in two SPMS cases related to various types of spontaneous speech tasks. We assumed the change of the cognitive load has a greater effect on spontaneous speech in MS patients than in controls. Two SPMS patients, and two sex-, age- and education matched healthy controls were studied. We applied verbal fluency tests (phonemic, episodic, semantic, verb), digit span test, non-word repetition test, Corsi Block Tapping Test, Stroop Colour and Word Test, and Trail Making Test. Token Test was used to measure speech comprehension. The four speech tasks required relatively different degrees of cognitive effort: (a) spontaneous narrative about own life; (b) event description; (c) picture description; (d) narrative recall. Our results show that there are differences between MS patients and controls: MS patients produced slower speech and articulation rate, and they had more and longer pauses in every speech task. Speech tasks and the degree of the cognitive load had a greater effect on MS patients than on control speakers.