Information processing speed in multiple sclerosis is associated with higher disability level

Information processing speed (IPS) impairment is a disabling cognitive symptom often present in people with multiple sclerosis (PwMS). IPS is the foundation of higher order cognitive processes, and therefore IPS dysfunction significantly lowers quality of live. Early identification of PwMS at risk for IPS decline is necessary in order to provide timely cognitive rehabilitation and psychoeducation. As such, identifying who will or will not develop IPS impairment over time is important. Here, we investigated retrospectively which characteristics were associated with IPS impairment in a real-life sample of 218 PwMS (158 female; age M=47±12.7; baseline disease duration M=9.8±9.9) that visited the Noorderhart Rehabilitation and MS Centre in Overpelt (Belgium). IPS decline was determined based on performance on the Symbol Digit Modalities Test (SDMT), with two threshold settings: (1) minus 1.5 standard deviation, and (2) minus eight points decline of raw score. Next to SDMT scores,...Show moreInformation processing speed (IPS) impairment is a disabling cognitive symptom often present in people with multiple sclerosis (PwMS). IPS is the foundation of higher order cognitive processes, and therefore IPS dysfunction significantly lowers quality of live. Early identification of PwMS at risk for IPS decline is necessary in order to provide timely cognitive rehabilitation and psychoeducation. As such, identifying who will or will not develop IPS impairment over time is important. Here, we investigated retrospectively which characteristics were associated with IPS impairment in a real-life sample of 218 PwMS (158 female; age M=47±12.7; baseline disease duration M=9.8±9.9) that visited the Noorderhart Rehabilitation and MS Centre in Overpelt (Belgium). IPS decline was determined based on performance on the Symbol Digit Modalities Test (SDMT), with two threshold settings: (1) minus 1.5 standard deviation, and (2) minus eight points decline of raw score. Next to SDMT scores, demographic information was collected (sex, age, educational level) as well as MS-specific characteristics (disease severity [measured with the EDSS], disease duration, MS subtype), and psychological measures (fatigue [FSMC], depression and anxiety [HADS]). The analyses at baseline showed that EDSS score (impaired median=4 [2.5-6]; preserved median=2 [1.1-3.5]; d=0.9), disease duration (impaired M=11±10.8; preserved M=7±7.6; ƞ2=0.04), MS subtype (V=0.26), and perceived fatigue (impaired M=68.2±18.5; preserved M=53.5±20.8; d=0.75) were significantly higher/ progressive for IPS impaired PwMS (N=134) compared to preserved (N=84). Measured over time (average of three years), nine PwMS (N=50) were found to decline from preserved IPS functioning into impairment, independent of threshold setting for impairment. However, for both thresholds no longitudinal differences between IPS impaired and preserved PwMS were found. Our results demonstrate that IPS impairment is very prevalent in PwMS (61% at baseline) and is associated with higher levels of disability (more progressive subtype, longer disease duration, higher disease severity) and more fatigue. Worsening of these factors indicate the need to pay extra attention to IPS functioning. Secondly, IPS impairment does not develop quickly, with only a few PwMS (9/50) who decline into IPS impairment in a three-year period. It is recommended to start early with regular measurements of cognitive functioning to detect initial IPS changes.Show less

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Information processing speed in multiple sclerosis is associated with higher disability level