Posts Tagged Somatosensory Disorders
[DOCTORAL DISSERTATION] Upper extremity disability after stroke. Psychometric properties of outcome measures and perceived ability to perform daily hand activities – Full Text
Department of Health Sciences, Physiotherapy, Lund University
Date of issue 2016-10-08
Author(s) Elisabeth Ekstrand
Disability of the upper extremity is common after stroke. To be able to evaluate recovery and effects of interventions there is a need for stable and precise outcome measures. In order to design and target efficient rehabilitation interventions it is important to know which factors that affect the ability to perform daily hand activities. At the time when the studies in this thesis were planned there was limited knowledge of the psychometric properties of outcome measures for persons with mild to moderate impairments of the upper extremity after stroke. There was also a lack of knowledge of which daily hand activities these persons perceive difficult to perform and which factors are associated with the performance.
The overall aim of this thesis was to evaluate the psychometric properties of outcome measures for upper extremity after stroke, and to describe which daily hand activities persons with mild to moderate impairments in upper extremity after stroke perceive difficult to perform and identify associated factors with their performance.
In paper I – IV, between 43 and 45 participants were included. Muscle strength in the upper extremity, somatosensation (active touch), dexterity and self-perceived ability to perform daily hand activities were assessed twice, one to two weeks apart. In paper V, 75 participants were included and the evaluated measures of the upper extremity were used together with other stroke specific outcomes to cover important aspects of functioning and disability according to the International Classification of Functioning, Disability and Health (ICF). Test-retest analyses for continuous data were made with the Intraclass Correlation Coefficient (ICC), the Change in Mean, the Standard Error of Measurement (SEM) and the Smallest Real Difference (SRD) (Paper I, III and IV). For ordinal data the Kappa coefficient and the Elisabeth Svensson rank-invariant method were used (Paper II and III). For analyses of convergent validity the Spearman’s correlation coefficient (rho) was calculated (Paper III). The ability to perform daily hand activities and the associations with potential factors were evaluated by univariate and multivariate linear regression models (Study V).
The results showed that outcome measures for isometric and isokinetic muscle strength, active touch, dexterity and self-perceived daily hand activities have high test-retest agreements and can be recommended for persons with mild to moderate impairments in the upper extremity after stroke (Paper I to IV). Isometric strength measurements had lower measurement errors than isokinetic measurements and might be preferred (Paper I). The outcomes of dexterity showed learning effects (Paper III) and the ratings of perceived daily hand activities (Paper IV) had relatively high random measurement errors which must be taken into account when recovery and effects of interventions are evaluated. The three evaluated dexterity measures were partly related and can complement each other (Paper IV). Daily hand activities that require bimanual dexterity were perceived most difficult to perform, and dexterity and participation were the strongest contributing factors for performing daily hand activities after stroke (Paper V).
In conclusion, this thesis has shown that outcome measures assessing functioning and disability of upper extremity after stroke are reliable and can be used in clinical settings and research. To increase the ability to perform daily hand activities, dexterity and perceived participation, in particular, should be considered in the assessments, goal-settings and rehabilitation after stroke.
[Editorial] Principles underlying post-stroke recovery of upper extremity sensorimotor function – a neuroimaging perspective – frontiers
A substantial proportion of stroke survivors suffers from long-term sensorimotor deficits of the contralesional arm and hand (1). Neuroimaging, using a diversity of methods, has the potential to uncover underlying principles of functional disabilities and recovery characterizing patient groups as well as individual variability (2-6). The present issue aimed at: i. revealing the physiological mechanisms and the long term course of stroke recovery with respect to site and size of lesions, ii. correlating behavioral deficits and electrophysiological parameters with imaging patterns; iii. delineating neural networks involved; and iv. identifying sites where interventions enhance the recovery process.
Seitz and Donnan give an overview of mechanisms and disease-related limitations in post-stroke recovery (7). They address two informative subsections delineating time courses of the recovery process and state-of-the-art of neurorehabilitative training to improve the stroke-induced neurological deficit. Auriat et al. complete this clinical perspective with an overview on the use of transcranial magnetic stimulation and multimodal neuroimaging to estimate functional resources post-stroke (8). They provide a review of data from studies utilizing DTI, MRS, fMRI, EEG and brain stimulation techniques, focusing on TMS and its combination with uni- and multi-modal neuroimaging methods with respect to their benefits and limitations. Falcon et al. used “The Virtual Brain (TVB)”, an open source platform based on local biophysical models (9). Using this platform they simulated individuals’ brain activity linking structural data directly to a TVB model. Correlating TVB parameters with graph analysis metrics they obtained evidence for a shift of global to local dynamics in chronic stroke patients. Buetefisch (10) reviews the role of an intact contralesional motor cortex (M1) in post-stroke recovery of upper extremity motor function. The impact of the contralesional M1, on the lesioned motor cortex, seems to be promoting activity in the acute and inhibiting it in the chronic stage. Supportive evidence comes from animal studies including changes in neurotransmitter systems, dendritic growth and synapse formation. Thus, the contralesional M1 may represent a treatment target during rehabilitation. Sharma and Baron (11) report a fMRI study of a finger-thumb opposition sequence in chronic, well-recovered subcortical stroke patients. Using independent component analysis they could show that recovery of motor function involved pre-existing cortical networks contributing to recovery in a differentiated manner. The study of Abela et al. (12) complements these investigations of functional networks associated with recovery in the case of cortical sensorimotor stroke. The structural covariance network in patients recovering from hand paresis encompassed (i) a cortico-striato-thalamic loop involved in motor execution and (ii) higher order sensorimotor cortices affected by the stroke lesions. The network emerged in the early chronic stage post-stroke, was related to grey matter volume increases in the ipsilesional medio-dorsal thalamus, and its expression depended on an interaction of recovered hand function and the lesion size.Bannister et al. (13) report about neuroimaging evidence for the significance of the contralesional hemisphere in the recovery process after hemispheric supratentorial ischemic stroke, thus supplementing the review of Buetefisch (see above, 10). They followed the time course of touch sensation in the upper extremity using resting state – fMRI to explore functional connectivity. Improvement of touch sensation was related to changes in the contralesional hemisphere and cerebellum: 1. an increase in connectivity strength between the secondary somatosensory area seed and both inferior parietal cortex and middle temporal gyrus as well as the thalamus seed and cerebellum; and 2. a decrease in connectivity strength between SI seed and the cerebellum. Primassin et al. dealed with four exemplary cases in which motor and language domains were affected differently (14). They focused on dissociative outcomes after seven weeks of rehabilitative treatment following on the predominant failure at baseline. Primarily, precise location of the lesions in the corticospinal tract and/or fasciculus arcuatus, respectively, turned out to be critical for recovery. Motor and language improvement seemed to occur together, rather than to compete for recovery resources.
Ben-Shabat et al. investigated changes in human proprioception, its specific brain activation, laterality and changes following stroke (15). Brain activation involved the supramarginal gyrus (SMG) and dorsal premotor cortex (PMd) with a prominent lateralization in the former. Lateralization was diminished in three patients exhibiting proprioceptive deficits post-stroke and a common lesion within the thalamus. The findings underline the role of SMG and dPM in spatial processing and motor control.
Brugger et al. investigated the intriguing role of supplementary motor complex (SMC) and disturbed motor control, a retrospective clinical and lesion analysis of ten patients presenting anterior cerebral artery stroke (16). In the very acute phase alien hand syndrome (AHS) dominated accompanied by failed conscious awareness of motor intention and a missing sense of agency while performing externally triggered movements. In the follow-up motor signs specifically related to AHS, i.e. disturbed self-initiated movements, grasping and intermanual conflict, were mainly related to lesions of the pre-supplementary motor area and medial cingulate cortex.
Camilleri et al. (17) studied the neural substrate underlying the performance of the trail making test (TMT) that is often used in the follow-up of stroke. In healthy volunteers they found that performance in terms of motor speed to be related to the local brain volume of a region in the lower bank of the left inferior sulcus. Conjunction analysis of four connectivity approaches has shown this area to represent a constituent of the so-called multiple demand network, highlighting the TMT as related rather to executive than primary motor function.
In sum, the neurological deficits, recovery mechanisms and the prognosis for recovery after stroke are hot spots of clinical neurology and systems neuroscience research. Multimodal imaging, applied neurophysiology and careful neurobehavioral in-vivo correlations have opened new vistas on the pathophysiological mechanisms underlying post-stroke recovery of upper extremity sensorimotor deficits paving new avenues for future research.
Keywords: stroke recovery, multimodal neuroimaging, computational biophysical modeling, motor control, Motor Imagery, Somatosensory Disorders, perilesional plasticity, network reorganization, structural covariance, Neurorehabilitation