Affiliation:
1. Corinne Goldsmith Dickinson Center for Multiple Sclerosis, Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
2. Department of Health Studies and Applied Educational Psychology, Teachers College, Columbia University, New York, NY, USA
Abstract
Background: Word-finding difficulty is prevalent but poorly understood in persons with relapsing-remitting multiple sclerosis (RRMS). Objective: The objective was to investigate our hypothesis that phonological processing ability is below expectations and related to word-finding difficulty in patients with RRMS. Method: Data were analyzed from patients with RRMS ( n = 50) on patient-reported word-finding difficulty (PR-WFD) and objective performance on Wechsler Individual Achievement Test, Fourth Edition (WIAT-4) Phonemic Proficiency (PP; analysis of phonemes within words), Word Reading (WR; proxy of premorbid literacy and verbal ability), and Sentence Repetition (SR; auditory processing of word-level information). Results: Performance (mean (95% confidence interval)) was reliably lower than normative expectations for PP (−0.41 (−0.69, −0.13)) but not for WR (0.02 (−0.21, 0.25)) or SR (0.08 (−0.15, 0.31). Within-subjects performance was worse on PP than on both WR ( t(49) = 4.00, p < 0.001, d = 0.47) and SR ( t(49) =3.76, p < 0.001, d = 0.54). Worse PR-WFD was specifically related to lower PP ( F2,47 = 6.24, p = 0.004, η2 = 0.21); worse PP performance at PR-WFD Often ( n = 13; −1.16 (−1.49, −0.83)) than Sometimes ( n = 17; −0.14 (−0.68, 0.41)) or Rarely ( n = 20; −0.16 (−0.58, 0.27). PR-WFD was unrelated to WR or SR ( ps > 0.25). Conclusion: Phonological processing was below expectations and specifically linked to word-finding difficulty in RRMS. Findings are consistent with early disease-related cortical changes within the posterior superior temporal/supramarginal region. Results inform our developing model of multiple sclerosis-related word-finding difficulty.