Background and Purpose Patient-reported outcome measures have been found useful in many disciplines but have received limited evaluation after stroke. The current study investigated the relationship that patient-reported measures have with standard impairment and disability scales after stroke. Methods Patients with motor deficits after stroke were scored on standard assessments including NIH Stroke Scale (NIHSS), modified Rankin Scale (mRS), and Fugl-Meyer motor scale (FM), and on two patient-reported measures, the hand function domain of the Stroke Impact Scale (SIS), which documents difficulty of hand motor usage, and the amount of use portion of the Motor Activity Log (MAL), which records amount of arm motor usage. Results The 43 participants had mild disability (median mRS=2), moderate motor deficits (FM=46 ± 22), and mild cognitive/language deficits. The two patient-reported outcome measures, SIS and MAL, were sensitive to the presence of arm motor deficits. Of 21 patients classified as having minimal or no impairment or disability by the NIHSS or mRS (score of 0-1), 15 (71%) reported difficulty with hand movements by the SIS score or reduced arm use by the MAL score. Furthermore, of 14 patients with a normal exam, 10 (71%) reported difficulty with hand movements or reduction in arm use. Conclusions Patient-reported measures were a unique source of insight into clinical status in the current population. Motor deficits were revealed in a majority of patients classified by standard scales as having minimal or no disability, and in a majority of patients classified as having no deficits.

While the corpus callosum (CC) is important to normal sensorimotor function, its role in motor function after stroke is less well understood. This study examined the relationship between structural integrity of the motor and sensory sections of the CC, as reflected by fractional anisotropy (FA), and motor function in individuals with a range of motor impairment level due to stroke. Fifty-five individuals with chronic stroke (Fugl-Meyer motor score range 14 to 61) and 18 healthy controls underwent diffusion tensor imaging and a set of motor behavior tests. Mean FA from the motor and sensory regions of the CC and from corticospinal tract (CST) were extracted and relationships with behavioral measures evaluated. Across all participants, FA in both CC regions was significantly decreased after stroke (p < 0.001) and showed a significant, positive correlation with level of motor function. However, these relationships varied based on degree of motor impairment: in individuals with relatively less motor impairment (Fugl-Meyer motor score > 39), motor status correlated with FA in the CC but not the CST, while in individuals with relatively greater motor impairment (Fugl-Meyer motor score ≤ 39), motor status correlated with FA in the CST but not the CC. The role interhemispheric motor connections play in motor function after stroke may differ based on level of motor impairment. These findings emphasize the heterogeneity of stroke, and suggest that biomarkers and treatment approaches targeting separate subgroups may be warranted.

Advances in neuroimaging have enabled the mapping of white matter connections across the entire brain, allowing for a more thorough examination of the extent of white matter disconnection after stroke. To assess how cortical disconnection contributes to motor impairments, we examined the relationship between structural brain connectivity and upper and lower extremity motor function in individuals with chronic stroke. Forty-three participants [mean age: 59.7 (611.2) years; time poststroke: 64.4 (658.8) months] underwent clinical motor assessments and MRI scanning. Nonparametric correlation analyses were performed to examine the relationship between structural connectivity amid a subsection of the motor network and upper/lower extremity motor function. Standard multiple linear regression analyses were performed to examine the relationship between cortical necrosis and disconnection of three main cortical areas of motor control [primary motor cortex (M1), premotor cortex (PMC), and supplementary motor area (SMA)] and motor function. Anatomical connectivity between ipsilesional M1/SMA and the (1) cerebral peduncle, (2) thalamus, and (3) red nucleus were significantly correlated with upper and lower extremity motor performance (P 0.003). M1-M1 interhemispheric connectivity was also significantly correlated with gross manual dexterity of the affected upper extremity (P 5 0.001). Regression models with M1 lesion load and M1 disconnection (adjusted for time poststroke) explained a significant amount of variance in upper extremity motor performance (R 2 5 0.36-0.46) and gait speed (R 2 5 0.46), with M1 disconnection an independent predictor of motor performance. Cortical disconnection, especially of ipsilesional M1, could significantly contribute to variability seen in locomotor and upper extremity motor function and recovery in chronic stroke. Hum Brain Mapp 39:120-132, 2018.V C 2017 Wiley Periodicals, Inc.

Although intermixing different motor learning tasks via random schedules enhances long-term retention compared with "blocked" schedules, the mechanism underlying this contextual interference effect has been unclear. Furthermore, previous studies have reported inconclusive results in individuals poststroke. We instructed participants to learn to produce three grip force patterns in either random or blocked schedules and measured the contextual interference effect by long-term forgetting: the change in performance between immediate and 24-h posttests. Nondisabled participants exhibited the contextual interference effect: no forgetting in the random condition but forgetting in the blocked condition. Participants at least 3 mo poststroke exhibited no forgetting in the random condition but marginal forgetting in the blocked condition. However, in participants poststroke, the integrity of visuospatial working memory modulated long-term retention after blocked schedule training: participants with poor visuospatial working memory exhibited little forgetting at 24 h. These counterintuitive results were predicted by a computational model of motor memory that contains a common fast process and multiple slow processes, which are competitively updated by motor errors. In blocked schedules, the fast process quickly improved performance, therefore reducing error-driven update of the slow processes and thus poor long-term retention. In random schedules, interferences in the fast process led to slower change in performance, therefore increasing error-driven update of slow processes and thus good long-term retention. Increased forgetting rates in the fast process, as would be expected in individuals with visuospatial working memory deficits, led to small updates of the fast process during blocked schedules and thus better long-term retention. stroke; neurorehabilitation; motor learning; computational neuroscience DURING NEUROREHABILITATION after brain injury, but also in activities such as sports, technical training, and music, one must often learn, or relearn, multiple motor tasks within a given period. Intermixing the learning of different tasks via random schedules reduces performance during training but enhances long-term retention compared with blocked schedules, (e.g., Schmidt and Lee 1999;Shea and Morgan 1979;Tsuitsui et al. 1998). This phenomenon is known as the contextual interference (CI) effect.Despite close to a century of research (Pyle 1919), however, the mechanism underlying the CI effect are unclear. According to the "forgetting-reconstruction" hypothesis of the CI effect, short-term forgetting between successive presentations of the same task during random training requires the learner to "reconstruct the action plan at each presentation," resulting in stronger memory representations (Lee and Magill 1983;Lee et al. 1985). Recent computational models similarly suggest a crucial role of working memory in the CI effect. It has notably been proposed that motor adaptation occurs via simultaneous update of a fast proce...

Task performance for behaviors that engage motor cognitive processes may be particularly sensitive to age-related changes. One well-studied model of cognitive motor function involves engagement of action selection (AS) processes. In young adults, task conditions that add AS demands result in increased preparation times and greater engagement of bilateral dorsal premotor (PMd) and parietal cortices. The current study investigated the behavioral and neural response to a change in motor cognitive demands in older adults through the addition of AS to a movement task. Sixteen older adults made a joystick movement under two conditions during functional magnetic resonance imaging. In the AS condition, participants moved right or left based on an abstract rule; in the execution only (EO) condition, participants moved in the same direction on every trial. Across participants, the AS condition, as compared to the EO condition, was associated with longer reaction time and increased activation of left inferior parietal lobule. Variability in behavioral response to the AS task between participants related to differences in brain function and structure. Overall, individuals with poorer AS task performance showed greater activation in left PMd and dorsolateral prefrontal cortex and decreased structural integrity of white matter tracts that connect sensorimotor, frontal, and parietal regions--keys regions for AS task performance. Additionally, two distinct patterns of functional connectivity were found. Participants with a pattern of decreased primary motor-PMd connectivity in response to the AS condition, compared to those with a pattern of increased connectivity, were older and had poorer behavioral performance. These neural changes in response to increased motor cognitive demands may be a marker for age-related changes in the motor system and have an impact on the learning of novel, complex motor skills in older adults.