Phonological networks remain intact in multiple sclerosis

Multiple sclerosis (MS) is a neurological condition characterized by white and gray matter decline that leads to slower motor function and cognitive impairment. Although language remains relatively intact, individuals with MS often have word retrieval difficulties. Previous research suggests that these difficulties may be related to vocabulary, the number of words an individual knows, and other semantic aspects of language. However, few studies have examined phonological aspects of speech.

We examined speech in 89 individuals with MS and 88 age-matched neurotypical adults using a phonemic verbal fluency task. We took a network science approach, building a phonological network from participants' responses and their close phonological neighbors. We then examined the local network characteristics (degree, clustering coefficient) of participants' responses to assess whether responses differed between the groups.

Although individuals with MS produced fewer responses during the task, the network characteristics of their responses were similar to neurotypical adults, the control group. Moreover, lexical characteristics such as word length and lexical frequency were also similar between groups (model R² values < 1%). Finally, a forward flow analysis, which quantifies the phonological similarity between adjacent responses and provides a metric of how people search phonemic space, did not differ between groups.

Overall, these results suggest that phonological aspects of speech remain stable in individuals with MS. Word retrieval difficulties in MS may arise from neurological changes in semantic processes, in combination with other cognitive abilities such as speed of processing and executive function, which are common in MS. (PsycInfo Database Record (c) 2026 APA, all rights reserved).