The aim was to compare the effectiveness of dual-task training (DTT) compared to single mobility training (SMT) on dual-task walking, mobility and cognition, in persons with Multiple Sclerosis (pwMS). Forty pwMS were randomly assigned to the DTT or SMT groups. The DTT-group performed dual-task exercises using an interactive tablet-based application, while the SMT-group received conventional walking and balance exercises. Both interventions were supervised and identical in weeks (8) and sessions (20). Nine cognitive-motor dual-task conditions were assessed at baseline, after intervention and at 4-weeks follow-up (FU). The dual-task cost (DTC), percentage change of dual-task performance compared to single-task performance, was the primary outcome. Mobility and cognition were secondarily assessed. Mixed model analyses were done with group, time and the interaction between group and time as fixed factors and participants as random factors. Significant time by group interactions were found for the digit-span walk and subtraction walk dual-task conditions, with a reduction in DTC (gait speed) for the DTT maintained at FU. Further, absolute dual-task gait speed during walking over obstacles only improved after the DTT. Significant improvements were found for both groups in various motor and cognitive measures. However, the DTT led to better dual-task walking compared to the SMT.

Background. Simultaneous execution of motor and cognitive tasks can result in worsened performance on one or both tasks, indicating cognitive-motor interference (CMI). A growing amount of research on CMI in persons with multiple sclerosis (pwMS) is observed. However, psychometric properties of dual-task outcomes have been scarcely reported. Objective. To investigate the between-day test-retest reliability of the motor and cognitive dual-task costs (DTCs) during multiple CMI test conditions with various task complexities in pwMS and matched healthy controls (HCs). Methods. A total of 34 pwMS (Expanded Disability Status Scale score 3.0 ± 0.8) and 31 HCs were tested and retested on 3 single cognitive, 4 single motor, and 12 cognitive-motor dual tasks. Cognitive tasks included serial subtraction by 7, titrated digit span backward, and auditory vigilance. Motor tasks were walking at self-selected speed, over obstacles, crisscross, and while carrying a water-filled cup. Outcome measures were cognitive and motor DTC, calculated as percentage change of dual-task performance compared with single-task performance. Intraclass correlations (ICCs) and Spearman correlation coefficients were calculated as appropriate. Results. For DTC_motor of gait speed, ICCs ranged from 0.45 to 0.81 and Spearman correlations from 0.74 to 0.82. For DTC_cognitive, ICCs ranged from −0.18 to 0.49 and Spearman correlations from −0.28 to 0.26. Reliability depended on the type of motor and cognitive task. Conclusion. Reliability of the DTC_motor was, overall, good, whereas that of the DTC_cognitive was poor. The “walking” and “cup” dual-task conditions were the most reliable regardless of the integrated cognitive task.

Background: Performing a cognitive task and a motor task simultaneously is an everyday act that can lead to decreased performance on both tasks. Objective: To provide insight into the neural correlates associated with cognitive–motor dual tasking in individuals with a neurologic disorder. Method: We searched the PubMed and Web of Science databases for studies that had been published up to January 16th, 2019. Studies investigating the neural correlates of cognitive–motor dual task performance in individuals with a variety of neurologic disorders were included, independently from whether the study included healthy controls. Clinical and imaging data were abstracted for the comparison between single tasks and a dual task in the individuals with a neurologic disorder and for the comparison between the healthy controls and the individuals with a neurologic disorder. Results: Eighteen studies met the inclusion criteria. Study populations included individuals with Parkinson disease, multiple sclerosis, mild cognitive impairment, Alzheimer disease, traumatic brain injury, and stroke. Neuroimaging types used to study the neural correlates of cognitive–motor dual tasking during upper limb or gait tasks included fMRI, functional near-infrared spectroscopy, EEG, and PET. Conclusion: Despite large heterogeneity in study methodologies, some recurrent patterns were noted. Particularly, in neurologic patients, an already higher brain activation during single tasks was seen compared with healthy controls, perhaps compromising the patients’ ability to further adapt brain activation with increasing load during dual tasking and resulting in reduced behavioral dual task performance.

Background: Day-to-day reliability and cut-off values to detect abnormal walking fatigability (WF) remain to be investigated in persons with multiple sclerosis (pwMS). Methods: In all, 49 pwMS (mean Expanded Disability Status Scale (EDSS) ± standard deviation (SD): 3.3 ± 1.9) and 28 matched healthy controls (HC) performed the six-minute walking test (6MWT) on two different days to determine day-to-day reliability (intraclass correlation coefficient (ICC)) and limits of agreement (LOA) for five different equations of WF. Objective: To examine day-to-day reliability, agreement and discriminative validity for measuring WF. Results and conclusion: WF expressed as the ratio between the first and sixth minute had the best day-to-day reliability (ICC’s range of 0.76–0.95 and 0.60–0.86, respectively) in both pwMS and HC, while LOA were 15% and 7%, respectively. Ecological validity and clinical importance should be further investigated.

Background: Interest toward dual-task training (DTT) is increasing as traditional interventions may not prepare patients to adequately face the challenges of most activities of daily living. These usually involve simultaneous cognitive and motor tasks, and they often show a decline in performance. Cognitive-motor interference (CMI) has been investigated in different neurological populations, but limited evidence is present for people with multiple sclerosis (MS). The use of computerized tools is mandatory to allow the application of more standardized assessment and rehabilitation intervention protocols and easier implementation of multicenter and multilanguage studies. Objective: To describe the design and development of CMI-APP, an adaptive and interactive technology tablet-based app, and to present the preliminary results of a multicenter pilot study involving people with MS performed in several European centers for evaluating the feasibility of and adherence to a rehabilitation program based on CMI-APP. Methods: CMI-APP includes user-friendly interfaces for personal data input and management, assessment of CMI, and DTT. A dedicated team developed CMI-APP for Android tablets above API level 14 (version 4.0), using C# as the programming language and Unity and Visual Studio as development tools. Three cognitive assessment tests for working memory, information processing speed, and sustained attention and four motor assessment tests for walking at different difficulty levels were implemented. Dual cognitive-motor tasks were performed by combining single cognitive and motor tasks. CMI-APP implements exercises for DTT involving the following 12 cognitive functions: sustained attention, text comprehension, verbal fluency, auditory discrimination, visual discrimination, working memory, information processing speed, auditory memory, visual memory, verbal analog reasoning, visual analog reasoning, and visual spatial planning, which can be performed during walking or stepping on the spot. Fifteen people with MS (mean age 52.6, SD 8.6 years; mean disease duration 9.4, SD 8.4 years; mean Expanded Disability Status Scale score 3.6, SD 1.1) underwent DTT (20 sessions). Adherence to the rehabilitation program was evaluated according to the percentage of performed sessions, perceived exertion during the training (Borg 15-point Ratings of Perceived Exertion [RPE] Scale), and subjective experience of the training (Intrinsic Motivation Inventory [IMI]). Results: The adherence rate was 91%. DTT was perceived as “somewhat difficult” (mean RPE Scale score 12.6, SD 1.9). IMI revealed that participants enjoyed the training and felt that it was valuable and, to some extent, important, without feelings of pressure. They felt competent, although they did not always feel they could choose the exercises, probably because the therapist chose the exercises and many exercises had few difficulty levels. Conclusions: CMI-APP is safe, highly usable, motivating, and well accepted for DTT by people with MS. The findings are fundamental for the preparation of future large-sample studies examining CMI and the effectiveness of DTT interventions with CMI-APP in people with MS.