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<jats:p> Fatigue is one of the most common debilitating symptoms reported by persons with multiple sclerosis (MS). It reflects feelings of tiredness, lack of energy, low motivation, and difficulty in concentrating. It can be measured at a specific instant in time as a perception that arises from interoceptive networks involved in the regulation of homeostasis. Such ratings indicate the state level of fatigue and likely reflect an inability to correct deviations from a balanced homeostatic state. In contrast, the trait level of fatigue is quantified in terms of work capacity (fatigability), which can be either estimated (perceived fatigability) or measured (objective fatigability). Clinically, fatigue is most often quantified with questionnaires that require respondents to estimate their past capacity to perform several cognitive, physical, and psychosocial tasks. These retrospective estimates provide a measure of perceived fatigability. In contrast, the change in an outcome variable during the actual performance of a task provides an objective measure of fatigability. Perceived and objective fatigability do not assess the same underlying construct. Persons with MS who report elevated trait levels of fatigue exhibit deficits in interoceptive networks (insula and dorsal anterior cingulate cortex), including increased functional connectivity during challenging tasks. The state and trait levels of fatigue reported by an individual can be modulated by reward and pain pathways. Understanding the distinction between fatigue and fatigability is critical for the development of effective strategies to reduce the burden of the symptom for individuals with MS. </jats:p>

<jats:sec><jats:title>Background</jats:title><jats:p> Recovery of quiet standing balance early poststroke has been poorly investigated using repeated measurements. </jats:p></jats:sec><jats:sec><jats:title>Objective</jats:title><jats:p> To investigate (1) the time course of steady-state balance in terms of postural stability and inter-limb symmetry, and (2) longitudinal associations with lower limb motor recovery in the first 3 months poststroke. </jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p> Forty-eight hemiparetic subjects (age: 58.9 ± 16.1 years) were evaluated at weeks 3, 5, 8, and 12 poststroke. Motor impairments concerned the Fugl-Meyer assessment (FM-LE) and Motricity Index total score (MI-LE) or ankle item separately (MI-ankle). Postural stability during quiet 2-legged stance was calculated as the net center-of-pressure area (COP<jats:sub>Area</jats:sub>) and direction-dependent velocities (COP<jats:sub>Vel-ML</jats:sub> and COP<jats:sub>Vel-AP</jats:sub>). Dynamic control asymmetry (DCA) and weight-bearing asymmetry (WBA) estimated inter-limb symmetries in balance control and loading. Linear mixed models determined (1) time-dependent change and (2) the between- and within-subject associations between motor impairments and postural stability or inter-limb symmetry. </jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p> Time-dependent improvements were significant for FM-LE, MI-LE, MI-ankle, COP<jats:sub>Area</jats:sub>, COP<jats:sub>Vel-ML</jats:sub>, and COP<jats:sub>Vel-AP</jats:sub>, and tended to plateau by week 8. DCA and WBA did not exhibit significant change. Between-subject analyses yielded significant regression coefficients for FM-LE, MI-LE, and MI-ankle scores with COP<jats:sub>Area</jats:sub>, COP<jats:sub>Vel-ML</jats:sub>, and COP<jats:sub>Vel-AP</jats:sub> up until week 8, and with WBA until week 12. Within-subject regression coefficients of motor recovery with change in COP<jats:sub>Area</jats:sub>, COP<jats:sub>Vel-ML</jats:sub>, COP<jats:sub>Vel-AP</jats:sub>, DCA, or WBA were generally non-significant. </jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p> Postural stability improved significantly in the first 8 weeks poststroke, independent of lower limb motor recovery at the most affected side within subjects. Our findings suggest that subjects preferred to compensate with their less affected side, making metrics reflecting inter-limb asymmetries in balance invariant for change early poststroke. Clinical Trial Registration: Clinicaltrials.gov. unique identifier NCT03728036. </jats:p></jats:sec>

<jats:p> Visuospatial neglect (VSN) is a negative, strong, and independent predictor of poor outcome after stroke, and is associated with poorer upper limb (UL) motor recovery in terms of function or capacity (ie, in standardized, lab-based testing). Although the main aim of stroke rehabilitation is to re-establish optimal functioning in daily life, the impact of VSN on UL performance (ie, in unstructured, everyday environments) is largely unknown. In this proof of principle study, the impact of VSN on the strength of the association between UL motor function (Jamar Hand Dynamometer) and UL performance (Upper Limb Lucerne ICF-based Multidisciplinary Observation Scale) was investigated in 65 (hyper)acute first-ever stroke patients. In a moderator analysis, the interaction term was negative and significant, showing that VSN suppresses the use of UL motor function in daily life (ie, performance). This finding suggests that, when considering UL performance in the (hyper)acute phase after stroke, interventions aimed to reduce deficits in both UL motor function and visuospatial function should already be started in the acute stroke unit setting. </jats:p>