Phonological Fluency Strategy of Switching Differentiates Relapsing-Remitting and Secondary Progressive Multiple Sclerosis Patients

The strategies used to perform a verbal fluency task appear to be reflective of cognitive abilities necessary for successful daily functioning. In the present study, we explored potential differences in verbal fluency strategies (switching and clustering) used to maximize word production by patients with relapsing-remitting multiple sclerosis (RRMS) versus patients with secondary progressive multiple sclerosis (SPMS). We further assessed impairment rates and potential differences in the sensitivity and specificity of phonological versus semantic verbal fluency tasks in discriminating between those with a diagnosis of MS and healthy adults. We found that the overall rate of impaired verbal fluency in our MS sample was consistent with that in other studies. However, we found no differences between types of MS (SPMS, RRMS), on semantic or phonological fluency word production, or the strategies used to maximize semantic fluency. In contrast, we found that the number of switches differed significantly in the phonological fluency task between the SPMS and RRMS subtypes. The clinical utility of semantic versus phonological fluency in discriminating MS patients from healthy controls did not indicate any significant differences. Further, the strategies used to maximize performance did not differentiate MS subgroups or MS patients from healthy controls.