Emerging evidence indicates impairments in somatosensory function may be a major contributor to motor dysfunction associated with neurologic injury or disorders. However, the neuroanatomical substrates underlying the connection between aberrant sensory input and ineffective motor output are still under investigation. The primary somatosensory cortex (S1) plays a critical role in processing afferent somatosensory input and contributes to the integration of sensory and motor signals necessary for skilled movement. Neuroimaging and neurostimulation approaches provide unique opportunities to non-invasively study S1 structure and function including connectivity with other cortical regions. These research techniques have begun to illuminate casual contributions of abnormal S1 activity and connectivity to motor dysfunction and poorer recovery of motor function in neurologic patient populations. This review synthesizes recent evidence illustrating the role of S1 in motor control, motor learning and functional recovery with an emphasis on how information from these investigations may be exploited to inform stroke rehabilitation to reduce motor dysfunction and improve therapeutic outcomes.
Background/Objective. We investigated interhemispheric interactions in stroke survivors by measuring transcranial magnetic stimulation (TMS)–evoked cortical coherence. We tested the effect of TMS on interhemispheric coherence during rest and active muscle contraction and compared coherence in stroke and older adults. We evaluated the relationships between interhemispheric coherence, paretic motor function, and the ipsilateral cortical silent period (iSP). Methods. Participants with (n = 19) and without (n = 14) chronic stroke either rested or maintained a contraction of the ipsilateral hand muscle during simultaneous recordings of evoked responses to TMS of the ipsilesional/nondominant (i/ndM1) and contralesional/dominant (c/dM1) primary motor cortex with EEG and in the hand muscle with EMG. We calculated pre- and post-TMS interhemispheric beta coherence (15-30 Hz) between motor areas in both conditions and the iSP duration during the active condition. Results. During active i/ndM1 TMS, interhemispheric coherence increased immediately following TMS in controls but not in stroke. Coherence during active cM1 TMS was greater than iM1 TMS in the stroke group. Coherence during active iM1 TMS was less in stroke participants and was negatively associated with measures of paretic arm motor function. Paretic iSP was longer compared with controls and negatively associated with clinical measures of manual dexterity. There was no relationship between coherence and. iSP for either group. No within- or between-group differences in coherence were observed at rest. Conclusions. TMS-evoked cortical coherence during hand muscle activation can index interhemispheric interactions associated with poststroke motor function and potentially offer new insights into neural mechanisms influencing functional recovery.
Background Abnormal brain excitability influences recovery after stroke at which time a prolonged transcranial magnetic stimulation (TMS)-induced electromyographic (EMG) silent period is thought to reflect abnormal inhibitory interneuron excitability. Cortical excitability can be probed directly during the silent period using concurrent electroencephalography (EEG) of TMS-evoked responses. Objective The primary study objectives were to characterize TMS-evoked cortical potentials (TEPs) using EEG and to investigate associations with persistent hand and arm motor dysfunction in individuals with chronic stroke. Methods Thirteen participants with chronic stroke-related mild-moderate arm motor impairment and twelve matched controls completed a single TMS-EEG cortical excitability assessment. TEPs recorded from the vertex during cortical silent period (CSP) assessment and while at rest were used to evaluate differences in cortical excitability between stroke and control participants. Associations between TEPs and CSP duration with measures of upper extremity motor behavior were investigated. Results Significantly increased TEP component peak amplitudes and delayed latencies were observed for stroke participants compared to controls during CSP assessment and while at rest. Delayed early TEP component (P30) peak latencies during CSP assessment were associated with less manual dexterity. CSP duration was prolonged in stroke participants, and correlated with P30 peak latency and paretic arm dysfunction. Conclusions Abnormal cortical excitability directly measured by early TMS-evoked EEG responses during CSP assessment suggests abnormal cortical inhibition is associated with hand dysfunction in chronic stroke. Further investigation of abnormal cortical inhibition in specific brain networks is necessary to characterize the salient neurophysiologic mechanisms contributing to persistent motor dysfunction after stroke.
The Acute Care for Elders (ACE) Unit model improves cognitive and functional outcomes for hospitalized elders but reaches a small proportion of patients. To disseminate ACE Unit principles, we piloted the "Virtual ACE Intervention" that standardizes care processes for cognition and function without daily geriatrician oversight on two non-ACE units. The Virtual ACE Intervention includes staff training on geriatric assessments for cognition and function and on nurse-driven care algorithms. Completion of the geriatric assessments by nursing staff in patients aged 65 years and older and measures of patient mobility and prevalence of an abnormal delirium screening score were compared preintervention and postintervention. Postintervention, the completion of the assessments for current functional status and delirium improved (62.5% vs. 88.5%, p < .001) and (4.2% vs. 96.5%, p < .001). In a subsample analysis, in the postintervention period, more patients were up to the chair in the past day (36.4% vs. 63.5%, p = .04) and the prevalence of an abnormal delirium screening score was lower (13.6% vs. 4.8%, p = .16). The Virtual ACE Intervention is a feasible model for disseminating ACE Unit principles to non-ACE Units and may lead to increased adherence to care processes and improved clinical outcomes.
PurposeEmployee wellness is vital to creating high-quality employee–customer interactions, yet frontline service workers (FLSWs) do not typically engage in, or benefit from, wellness initiatives. This paper aims to conceptually model the interactive influences of organizational and employee factors in influencing FLSW involvement in wellness programs and provides suggestions on how service organizations can enhance wellness behaviors and outcomes.Design/methodology/approachThis paper builds upon classical and contemporary management theories to identify important gaps in knowledge about how employees and firms engage with wellness. Interactive psychology, emphasizing multidirectional interaction between person (employee) and situation (organization) wellness orientation, is introduced.FindingsThe paper develops a model that can be used to assess organizational wellness program effectiveness by emphasizing the interaction of employee and organizational wellness orientation. The model illustrates that wellness effectiveness relies equally on employee agency through an active wellness orientation matched with the organizational wellness orientation.Originality/valueThis paper questions the dominant approaches to assessing the effectiveness of workplace wellness initiatives, arguing for a more humanistic and agentic perspective rather than traditional organizationally centered fiscal measures.
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