Aberrant functional connectivity in brain networks associated with motor impairment after stroke is well described, but little is known about the association with somatosensory impairments. The objective of this cross-sectional observational study was to investigate the relationship between brain functional connectivity and severity of somatosensory impairments in the upper limb in the acute phase post stroke. Nineteen first-ever stroke patients underwent resting-state functional magnetic resonance imaging (rs-fMRI) and a standardized clinical somatosensory profile assessment (exteroception and higher cortical somatosensation) in the first week post stroke. Integrity of inter- and intrahemispheric (ipsilesional and contralesional) functional connectivity of the somatosensory network was assessed between patients with severe (Em-NSA< 13/32) and mild to moderate (Em-NSA> 13/32) somatosensory impairments. Patients with severe somatosensory impairments displayed significantly lower functional connectivity indices in terms of interhemispheric (p = 0.001) and ipsilesional intrahemispheric (p = 0.035) connectivity compared to mildly to moderately impaired patients. Significant associations were found between the perceptual threshold of touch assessment and interhemispheric (r = -0.63) and ipsilesional (r = -0.51) network indices. Additional significant associations were found between the index of interhemispheric connectivity and light touch (r = 0.55) and stereognosis (r = 0.64) evaluation. Patients with more severe somatosensory impairments have lower inter- and ipsilesional intrahemispheric connectivity of the somatosensory network. Lower connectivity indices are related to more impaired exteroception and higher cortical somatosensation. This study highlights the importance of network integrity in terms of inter- and ipsilesional intrahemispheric connectivity for somatosensory function. Further research is needed investigating the effect of therapy on the re-establishment of these networks.

Purpose: To investigate the relation between observed and perceived upper limb motor function in patients with chronic stroke. Material and methods: We investigated 32 patients at six months after stroke with the Fugl-Meyer Assessment (observed function) and hand subscale of the Stroke Impact Scale (perceived function). Spearman correlation was calculated to relate observed and perceived function. Through cut-off scores, we divided our sample in low (Fugl-Meyer Assessment <31/66) and good observed function, and low (hand subscale of Stroke Impact Scale <61/100) and good perceived function. Scatterplot and hierarchical clustering analysis was conducted to detect distinct groups. Results: A strong positive relation was found between observed and perceived function (r = 0.84). Three groups could be identified; a “low match group” of patients with low observed and low perceived function (n = 11, 34%), a “good match group” containing patients with good observed and good perceived function (n = 15, 47%), and a “mismatch group” comprising patients with good observed but low perceived function (n = 6, 19%). Conclusions: In our chronic sample, one in five patients showed good upper limb observed but low perceived function. Measuring both observed and perceived arm and hand function seems warranted together with considering a differential therapy approach for the distinct groups.

Background. Proportional motor recovery in the upper limb has been investigated, indicating about 70% of the potential for recovery of motor impairment within the first months poststroke. Objective. To investigate whether the proportional recovery rule is applicable for upper-limb somatosensory impairment and to study underlying neural correlates of impairment and outcome at 6 months. Methods. A total of 32 patients were evaluated at 4 to 7 days and 6 months using the Erasmus MC modification of the revised Nottingham Sensory Assessment (NSA) for impairment of (1) somatosensory perception (exteroception) and (2) passive somatosensory processing (sharp/blunt discrimination and proprioception); (3) active somatosensory processing was evaluated using the stereognosis component of the NSA. Magnetic resonance imaging scans were obtained within 1 week poststroke, from which lesion load (LL) was calculated for key somatosensory tracts. Results . Somatosensory perception fully recovered within 6 months. Passive and active somatosensory processing showed proportional recovery of 86% (95% CI = 79%-93%) and 69% (95% CI = 49%-89%), respectively. Patients with somatosensory impairment at 4 to 7 days showed significantly greater thalamocortical and insulo-opercular tracts (TCT and IOT) LL ( P < .05) in comparison to patients without impairment. Sensorimotor tract disruption at 4 to 7 days did not provide significant contribution above somatosensory processing score at 4 to 7 days when predicting somatosensory processing outcome at 6 months. Conclusions. Our sample of stroke patients assessed early showed full somatosensory perception but proportional passive and active somatosensory processing recovery. Disruption of both the TCT and IOT early after stroke appears to be a factor associated with somatosensory impairment but not outcome.

Background: A previously shown ‘mismatch’ group of patients with good observed upper limb (UL) motor function but low perceived UL activity at six months post stroke tends to use the affected UL less in daily life than would be expected based on clinical tests, and this mismatch may also be present at 12 months. We aimed to confirm this group in another cohort, to investigate the evolution of this group from six to 12 months, and to determine factors on admission to inpatient rehabilitation and at 6 months that can discriminate between mismatch and good match groups at 12 months.Methods: Persons after stroke were recruited on rehabilitation admission and re-assessed at six and 12 months. Observed UL function was measured with the upper extremity subscale of the Fugl-Meyer Assessment (FMA-UE) and perceived UL activity by the hand subscale of the Stroke Impact Scale 3.0 (SIS-Hand). We defined mismatch as good observed UL function (FMA-UE > 50/66) but low perceived activity (SIS-Hand≤75/100). Potential discriminators at admission and 6 months (demographic characteristics, stroke characteristics, UL somatosensory function, cognitive deficits, mental function and activity) were statistically compared for match and mismatch groups at 12 months.Results: We included 60 participants (female: 42%) with mean (SD) age of 65 (12) years. We confirmed a mismatch group of 11 (18%) patients at 6 months, which increased to 14 (23%) patients at 12 months. In the mismatch group compared to the good match group at 12 months, patients had a higher stroke severity and more somatosensory impairments on admission and at 6 months.Conclusions: We confirmed a group of patients with good observed UL function but low perceived activity both at six and at 12 months post stroke. Assessment of stroke severity and somatosensory impairments on admission into rehabilitation could determine mismatch at 12 months and might warrant intervention. However, large differences in clinical outcomes between patients in the mismatch group indicate the importance of tailoring training to the individual needs.

We investigated actual daily life upper limb (UL) activity in relation to observed UL motor function and perceived UL activity in chronic stroke in order to better understand and improve UL activity in daily life. In 60 patients, we collected (1) observed UL motor function (Fugl-Meyer Assessment (FMA-UE)), (2) perceived UL activity (hand subscale of the Stroke Impact Scale (SIS-Hand)), and (3) daily life UL activity (bilateral wrist-worn accelerometers for 72 h) data. Data were compared between two groups of interest, namely (1) good observed (FMA-UE >50) function and good perceived (SIS-Hand >75) activity (good match, n = 16) and (2) good observed function but low perceived (SIS-Hand ≤75) activity (mismatch, n = 15) with Mann–Whitney U analysis. The mismatch group only differed from the good match group in perceived UL activity (median (Q1–Q3) = 50 (30–70) versus 93 (85–100); p < 0.001). Despite similar observed UL motor function and other clinical characteristics, the affected UL in the mismatch group was less active in daily life compared to the good match group (p = 0.013), and the contribution of the affected UL compared to the unaffected UL for each second of activity (magnitude ratio) was lower (p = 0.022). We conclude that people with chronic stroke with low perceived UL activity indeed tend to use their affected UL less in daily life despite good observed UL motor function.

The role of somatosensory feedback in motor performance has been warranted in the literature. Although sensorimotor deficits are common after stroke, current rehabilitation approaches primarily focus on restoring upper limb motor ability. Evidence for integrative sensorimotor rehabilitation approaches is scarce, as is knowledge about neural correlates of somatosensory impairments after stroke and the effect of rehabilitation on brain connectivity level. Therefore, we aim to investigate changes in sensorimotor function and brain connectivity following a sensorimotor therapy program compared to an attention-matched motor therapy program for the upper limb after stroke. An assessor-blinded randomized controlled trial will be conducted. Sixty inpatient rehabilitation patients up to eight weeks after stroke will be included. Patients will be randomized to either an experimental group receiving sensorimotor therapy or a control group receiving attention-matched motor therapy for the upper limb, with both groups receiving conventional therapy. Thus, all patients will receive extra therapy, a total of 16 1-h sessions over four weeks. Patients will be assessed at baseline, after four weeks of training, and after four weeks of follow-up. Primary outcome measure is the Action Research Arm Test. Secondary outcome measures will consist of somatosensory, motor and cognitive assessments, and a standardized resting-state functional magnetic resonance imaging protocol. The integration of sensory and motor rehabilitation into one therapy model might provide the added value of this therapy to improve sensorimotor performance post stroke. Insight in the behavioral and brain connectivity changes post therapy will lead to a better understanding of working mechanisms of therapy and will provide new knowledge for patient-tailored therapy approaches. ClinicalTrials.gov, NCT03236376 . Registered on 8 August 2017.