The origin of contraversive pushing: evidence for a second graviceptive system in humans

Six-month outcomes and patterns of recovery for people with lateropulsion following stroke

PURPOSE

This study investigated the (1) six-month outcomes of individuals with lateropulsion; (2) the relationship between baseline measures (from in-patient hospitalisation) and six-month functional abilities; and (3) recovery patterns for lateropulsion in stroke survivors.

MATERIALS AND METHODS

Forty-one individuals with lateropulsion participated in this study. Measures of lateropulsion, postural function, and weight-bearing asymmetry in standing were taken initially and fortnightly over eight weeks. Functional independence and walking abilities were assessed at six months post-stroke.

RESULTS

Compared to individuals with moderate to severe lateropulsion, those with mild lateropulsion achieved higher levels of functional outcome at six months. However, there were a wide range of scores. Baseline lateropulsion severity explained 26% of the variation in functional outcome. A stronger correlation with functional outcome was observed for lateropulsion (-0.526) than function independence at baseline (0.384). For the task of standing with arm support, patterns of asymmetry were divergent at baseline, favouring either the paretic or non-paretic leg. Over the eight-week period, asymmetry moved towards the non-paretic leg and lateropulsion reduced consistently.

CONCLUSIONS

Individuals with lateropulsion can recover from lateropulsion and make meaningful functional gains, including some individuals with more severe lateropulsion. Lateropulsion severity is a key indicator of functional outcome post-stroke.IMPLICATIONS FOR REHABILITATIONIndividuals with lateropulsion can make significant gains in terms of mobility and functional abilities by six months post-stroke, learning to compensate for their verticality impairment in standing by loading their non-paretic leg.It is important that stroke survivors with lateropulsion, including those with moderate and severe lateropulsion, are provided with adequate rehabilitation to optimise their longer-term mobility and functional abilities.Routine screening of acute stroke survivors for lateropulsion is recommended, given lateropulsion may negatively impact longer-term functional outcomes in stroke survivors.Therapists should carefully analyse the weight-bearing pattern which an individual with lateropulsion adopts in standing and subsequently tailor treatment to target this.

The association between neuroimaging data and presence of lateropulsion after stroke

BACKGROUND

Post-stroke lateropulsion is prevalent and has been associated with varied lesion locations, but existing imaging studies are limited by small participant cohorts. Evidence to guide lateropulsion rehabilitation is also limited. Improved understanding of lesion localization associated with lateropulsion post-stroke may inform more targeted intervention approaches.

OBJECTIVES

This study investigated the associations between stroke neuroimaging data and presence of lateropulsion at inpatient rehabilitation admission.

METHODS

This prospective, observational study included participants aged ≥65 years, admitted for inpatient stroke rehabilitation. Using routinely collected clinical neuroimaging data, stroke type, location, and volume were reported, and their association with lateropulsion presence (Four-Point Pusher Score - 4PPS) at admission was explored.

RESULTS

Of 144 included participants, 82 (56.9%) had lateropulsion (4PPS ≥1). Lateropulsion presence was univariately associated with hemorrhagic stroke (p = 0.002), frontal cortical involvement (OR = 2.17, 95%CI 1.02-6.46), and white matter involvement (OR = 2.45, 95%CI 1.24-4.85), particularly frontal white matter (p = 0.021). Lesions involving the posterior limb of the internal capsule (OR = 2.88, 95% CI 1.14-7.27) and those involving the entire thalamus (OR = 1.0, p = 0.03) were associated with lateropulsion presence. When stratified by stroke type, no specific location was significantly associated with lateropulsion presence in hemorrhagic strokes. Among participants with ischemic stroke, involvement of the pre-central gyrus (OR = 2.45, 95%CI 1.05-5.76), post-central gyrus (OR = 2.76, 95%CI 1.15-6.60), inferior parietal cortex (OR = 3.95, 95%CI 1.43-10.90), and supramarginal gyrus (OR = 3.73, 95%CI 1.25-11.13) were associated with lateropulsion presence. The stroke laterality and size were not significantly associated with lateropulsion presence.

CONCLUSIONS

The findings indicate a role of network disconnection in the post-stroke lateropulsion presence. Future, larger-cohort lesion-network mapping studies are recommended.

Do we need to consider head-on-body position, starting roll position and presence of visuospatial neglect when assessing perception of verticality after stroke?

BACKGROUND AND OBJECTIVE

Considering various factors that influence the accuracy of the Subjective Visual Vertical (SVV) and Subjective Postural Vertical (SPV), standardization of assessment methods is needed. This retrospective study examined the contribution of Head-on-Body (HOB) position, starting roll position (SRP) and visuospatial neglect (VSN) to SVV and SPV constant errors (i.e. deviation from true vertical). Also, the contribution of HOB position and VSN presence to SVV and SPV variability (i.e. intra-individual consistency between trials) was assessed.

METHODS

First-ever unilateral hemispheric stroke survivors (<85 years; <100 days post-stroke) were assessed with three HOB positions (neutral, contralesional, and ipsilesional) and seven starting positions (20°Contralesional to 20° ipsilesional) of the laser bar and tilt chair. Linear mixed models were selected to evaluate the contribution of HOB, SRP, and VSN to SVV/SPV constant errors and variability.

RESULTS

Thirty-four subjects (24 VSN-/10 VSN+) were assessed. A tilted HOB position led to significantly higher constant errors for the SVV and SPV (the latter only in the VSN- group), and an increased SVV variability. SRP only significantly contributed to the SVV constant errors and only in the VSN- group. Furthermore, the presence of VSN resulted in a significantly higher SVV and SPV variability.

CONCLUSIONS

HOB position and the presence of SRP and VSN are important factors to consider during SVV and SPV measurements. Assessment with a neutral HOB position leads to more accurate results. HOB position and SRP influence the results of SVV and SPV differently in individuals with and without VSN, which highlights the relevance of VSN assessment.

Improving orientation with respect to gravity enhances balance and gait recovery after stroke: DOBRAS cohort

BACKGROUND

Lateropulsion is a deficit in body orientation with respect to gravity, frequent after stroke. Although it is a primary factor affecting mobility, the impact of its attenuation on balance and gait recovery has never been investigated. Moreover, most studies on the lateropulsion time-course focus on severe forms suspected to have a poor recovery, which is not proven.

OBJECTIVES

To investigate lateropulsion attenuation and test 2 hypotheses: 1) lateropulsion attenuation greatly contributes to balance and gait recovery and 2) severe forms of lateropulsion recover slower than moderate forms.

METHODS

This longitudinal study involved individuals included in the Determinants of Balance Recovery After Stroke (DOBRAS) cohort, after a first-ever hemispheric stroke, with data collected on day 30 (D30), D60 and D90 post-stroke. Body orientation with respect to gravity was assessed using the Scale for Contraversive Pushing (both scores and severity grouping), in parallel with balance (Postural Assessment Scale for Stroke) and gait (modified Fugl-Meyer Gait Assessment).

RESULTS

Among the 106 eligible individuals (mean age 66.5 [SD 9.7] years), on D30, 43 (41%) were considered upright and 63 (59%) showed lateropulsion: 30 (28%) moderate and 33 (31%) severe. Most individuals with lateropulsion (73%) improved their body orientation, progressing from severe to moderate lateropulsion, or becoming upright. However, half were still not upright on D90. The improvement in body orientation had a large impact on mobility, especially in individuals with severe lateropulsion, in whom it explained about 50% of balance and gait recovery between D30 and D60, then 20% (D60-D90). For moderate lateropulsion, its attenuation explained about 20% of balance and gait recovery until D90. Lateropulsion attenuation was not slower in individuals with severe forms.

CONCLUSIONS

Lateropulsion attenuation enhances balance and gait recovery in individuals after stroke suggesting that specific rehabilitation of body orientation with respect to gravity might help to recover mobility.

REGISTRATION

NCT03203109.

Lateropulsion in Right-Sided Stroke: Brain Anatomical Correlates of Severity and Duration

BACKGROUND AND PURPOSE

Lateropulsion (LP) is a profound disorder of postural control that has a significant impact on neurorehabilitation. Knowledge of relevant brain areas could guide decisions on appropriate intervention methods. Although LP severity and duration are highly variable in individuals with LP, imaging studies on LP have not sufficiently considered these aspects. The aim of this study was to investigate the lesion location in individuals after stroke and the correlation with LP duration and severity.

METHODS

A retrospective case-control study using voxel lesion symptom mapping (VLSM) in 74 individuals with right-sided brain lesion (49 with and 25 without LP) was performed to analyze the correlation between lesion location and LP severity. Duration was investigated in a subsample of 22 individuals with LP. LP was diagnosed by means of the Scale for Contraversive Pushing.

RESULTS

Individuals with LP showed significantly larger lesion sizes compared with the individuals with no LP. VLSM analysis of LP severity did not reveal statistically significant results. VLSM analysis showed a statistically significant association with longer LP duration for the inferior frontal gyrus, the hippocampus, the inferior parietal gyrus, the supramarginal gyrus, the angular gyrus, the temporal cortex, the sagittal stratum, and the superior longitudinal fasciculus.

DISCUSSION AND CONCLUSION

LP-relevant areas are located in the multisensory network. Areas of the frontoparietal network, which are related to spatial cognition, memory, and attention, were found to be relevant for duration and severity. The findings, especially those regarding duration involving the middle temporal cortex, could explain the better intervention outcomes for methods based more on implicit than on explicit knowledge of verticality.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1 available at: http://links.lww.com/JNPT/A433 ).

Predictors indicating the continuous need for a knee-ankle-foot orthosis in stroke patients at 1 month after onset

OBJECTIVES

To investigate predictors indicating the continuous need for a knee-ankle-foot orthosis (KAFO) at 1 month after stroke onset in patients who cannot walk without a KAFO in the acute period.

MATERIALS AND METHODS

We enrolled patients with severe hemiplegia (n = 139) who were unable to walk without a KAFO on day 10 from stroke onset. The patients were divided into two groups depending on the need for a KAFO at 1 month after the onset: the KAFO group and non-KAFO group. Logistic regression analysis was used to identify predictors of the continuous need for a KAFO at 1 month after stroke onset. In addition, significant predictors were analyzed using receiver operating characteristic curves.

RESULTS

The number of patients in the KAFO group and non-KAFO group was 72 (51.8 %) and 67 (48.2 %), respectively. Motor deficit, sensation disorder, severity of pusher syndrome, and body mass index were identified as predictors of the continuous need for a KAFO. Moreover, active range of motion of knee extension on the affected side was found to have the highest predictive ability, with an area under the receiver operating characteristic curve of 0.89 (95 % confidence interval, 0.83-0.94).

CONCLUSIONS

In this study, multiple factors were associated with the continuous need for a KAFO at 1 month after stroke onset. In particular, active range of motion of knee extension on the affected side is suggested to be a highly accurate predictor for the need for a KAFO in the subacute phase.

Nonhuman primates exploit the prior assumption that the visual world is vertical

When human subjects tilt their heads in dark surroundings, the noisiness of vestibular information impedes precise reports on objects' orientation with respect to Earth's vertical axis. This difficulty is mitigated if a vertical visual background is available. Tilted visual backgrounds induce feelings of head tilt in subjects who are in fact upright. This is often explained as a result of the brain resorting to the prior assumption that natural visual backgrounds are vertical. Here, we tested whether monkeys show comparable perceptual mechanisms. To this end we trained two monkeys to align a visual arrow to a vertical reference line that had variable luminance across trials, while including a large, clearly visible background square whose orientation changed from trial to trial. On ∼20% of all trials, the vertical reference line was left out to measure the subjective visual vertical (SVV). When the frame was upright, the monkeys' SVV was aligned with the gravitational vertical. In accordance with the perceptual reports of humans, however, when the frame was tilted it induced an illusion of head tilt as indicated by a bias in SVV toward the frame orientation. Thus all primates exploit the prior assumption that the visual world is vertical.NEW & NOTEWORTHY Here we show that the principles that characterize the human perception of the vertical are shared by another old world primate species, the rhesus monkey, suggesting phylogenetic continuity. In both species the integration of visual and vestibular information on the orientation of the head relative to the world is similarly constrained by the prior assumption that the visual world is vertical in the sense of having an orientation that is congruent with the gravity vector.

Primary Graviceptive System and Astasia: A Case Report and Literature Review

Astasia refers to the inability to maintain upright posture during standing, despite having full motor strength. Impairment of the vestibulocerebellar pathway, graviceptive system, and cingulate motor area have been proposed to be related to astasia. However, the responsible neural pathways remain unclear. We hypothesize that there is a common neural network behind astasia. To test the hypothesis, we reviewed all reported cases with astasia, including ours, and focused on the correlation between anatomical destruction and symptom presentation. A total of 26, including ours, non-psychogenic astasia patients were identified in the English literature. Seventy-three percent of them were associated with other neurologic symptoms and sixty-two percent of reported lesions were on the right side. Contralateral lateropulsion was very common, followed by retropulsion, when describing astasia. Infarction (54%) was the most reported cause. The thalamus (65%) was the most reported location. Infarctions were the fastest to recover (mean: 10.6 days), while lesions at the brainstem needed a longer time (mean: 61.6 days). By combining the character of lateropulsion in astasia and the presentation of an interrupted graviceptive system, we concluded that the primary graviceptive system may be the common neural network behind astasia. Future studies on astasia should focus on the pathological changes in the perception of verticality in the visual world and the body.

Post-Stroke Lateropulsion: Resolution and Function After Discharge From Inpatient Rehabilitation - A Cohort Study

Purpose

A person with post-stroke lateropulsion pushes their body toward their hemiparetic side and/or resists accepting weight onto their nonparetic side. Research findings regarding long-term persistence of lateropulsion and its association with function are lacking. This study reports associations between lateropulsion severity (Four Point Pusher Score - 4PPS) and functional outcome (Functional Independence Measure - FIM) at three months after discharge.

Methods

This prospective cohort study included 41 consecutive admissions to a stroke rehabilitation unit. Lateropulsion severity and FIM were measured at admission, discharge and three-month follow-up. Lateropulsion status at discharge, stroke laterality, ongoing physiotherapy after discharge, and demographic variables (age and sex) were tested for association with FIM change over the follow-up period.

Results

Complete data were available for 38 participants. Among these, 17 (44.7%) showed lateropulsion (4PPS ≥ 1) on admission, 9 (23.7%) showed persistent lateropulsion on discharge, and 7 (18.4%) showed persistent lateropulsion at three month follow-up. Improved functional status (FIM score) was seen at follow-up in those discharged with lateropulsion who had right-sided lesions but not in those with left-sided lesions.

Conclusions

Lateropulsion can continue to resolve after discharge from inpatient rehabilitation. Larger cohort studies are needed to further explore associations between persistent lateropulsion and long-term outcomes.

Thalamocortical disconnection involved in pusher syndrome

The presence of both isolated thalamic and isolated cortical lesions have been reported in the context of pusher syndrome-a disorder characterized by a disturbed perception of one's own upright body posture, following unilateral left- or right-sided stroke. In recent times, indirect quantification of functional and structural disconnection increases the knowledge derived from focal brain lesions by inferring subsequent brain network damage from the respective lesion. We applied both measures to a sample of 124 stroke patients to investigate brain disconnection in pusher syndrome. Our results suggest a hub-like function of the posterior and lateral portions of the thalamus in the perception of one's own postural upright. Lesion network symptom mapping investigating functional disconnection indicated cortical diaschisis in cerebellar, frontal, parietal and temporal areas in patients with thalamic lesions suffering from pusher syndrome, but there was no evidence for functional diaschisis in pusher patients with cortical stroke and no evidence for the convergence of thalamic and cortical lesions onto a common functional network. Structural disconnection mapping identified posterior thalamic disconnection to temporal, pre-, post- and paracentral regions. Fibre tracking between the thalamic and cortical pusher lesion hotspots indicated that in cortical lesions of patients with pusher syndrome, it is disconnectivity to the posterior thalamus caused by accompanying white matter damage, rather than the direct cortical lesions themselves, that lead to the emergence of pusher syndrome. Our analyses thus offer the first evidence for a direct thalamo-cortical (or cortico-thalamic) interconnection and, more importantly, shed light on the location of the respective thalamo-cortical disconnections. Pusher syndrome seems to be a consequence of direct damage or of disconnection of the posterior thalamus.

Dynamic changes of the direction and angle of radiographic ocular lateral deviation in patients with lateropulsion after stroke onset

OBJECTIVE

To examine if radiographic ocular lateral deviation (rOLD) could be provoked in stroke patients with mild-to-moderate lateropulsion according to vertical perception.

METHODS

In this single-center, retrospective study, acute stroke patients with mild-to-moderate lateropulsion assessed by the Scale for Contraversive Pushing were enrolled. Computed tomography or magnetic resonance imaging was performed on all patients on admission and then according to their conditions. The direction and angle of rOLD were compared among three groups according to the responsible lesion: lateral medullary (LM), pontine (P), and hemispheric (H).

RESULTS

Sixty-six patients (male, 47; average age, 67 years) were enrolled and divided into the LM (n = 37), P (n = 8), and H (n = 21) groups. All patients had body tilt. Patients in the LM group showed body tilt to the ipsilesional side during hospitalization, while those in the P and H groups tilted to the contralesional side. All patients had rOLD at the final assessment at an average of 13 days after onset; patients in the P and H groups showed contralateral rOLD, while those in the LM group showed ipsilateral rOLD if they did not have cerebellar or pontine lesions. Significant decreases in the angle and changes in direction of rOLD according to lesion site were observed during hospitalization.

CONCLUSION

Serial changes in rOLD findings after stroke onset are different according to the responsible lesion. The direction of rOLD in most patients is in accordance with vertical perception after the acute stage of stroke.

Lateropulsion with active pushing in stroke patients: its link with lesion location and the perception of verticality. A systematic review

BACKGROUND

Lateropulsion with active Pushing (LwP) is characterized by impairments in postural control. Previous research suggests an association between LwP, lesion location and verticality misperception. This first-ever systematic review evaluates the association between LwP, lesion location and the perception of verticality (PROSPERO: CRD42020159248).

METHODS

PubMed, Web of Science, REHABDATA, Embase, Cochrane Library and PEDro were systematically searched on December 16, 2021. Studies were included when examining lesion location or perception of verticality (Subjective Haptic, Visual or Postural Vertical) in supratentorial stroke patients showing LwP. Two reviewers independently screened and assessed risk of bias using the Newcastle Ottawa Scale. Data were qualitatively analyzed and extracted.

RESULTS

Nineteen studies were included, examining a total of 340 LwP patients. Lesions in: the thalamus, internal capsule, inferior parietal lobule at the junction of the postcentral gyrus, the posterior insula and the superior temporal gyrus, were associated with LwP. Whereas all studies examining the Subjective Postural and Haptic Vertical (haptic only examined once) reported a significant increased deviation in LwP patients, inconsistent results were found for the Subjective Visual Vertical. Furthermore, the Subjective Visual and Postural Vertical showed inconsistent results for magnitude, direction and variability of this deviation.

DISCUSSION

A complex brain network, rather than only one brain region, seems responsible for body control with respect to gravity. A disruption within this network might lead to a bias in the construction of a correct internal reference frame, crucial for perceiving verticality. There was an association of LwP with verticality misperception in all three modalities.

Spatial neglect encompasses impaired verticality representation after right hemisphere stroke

Spatial neglect after right hemisphere stroke (RHS) was recently found to encompass lateropulsion, a deficit in body orientation with respect to gravity caused by altered brain processing of graviception. By analogy, we hypothesized that spatial neglect after RHS might encompass an altered representation of verticality. We also assumed a strong relation between body neglect and impaired postural vertical, both referring to the body. To tackle these issues, we performed contingency and correlation analyses between two domains of spatial neglect (body, extra-body) and two modalities of verticality perception (postural, visual) in 77 individuals (median age = 67) with a first-ever subacute RHS (1-3 months). All individuals with a transmodal (postural and visual) tilt in verticality perception (n = 26) had spatial neglect, but the reverse was not found. Correlation and multivariate analyses revealed that spatial neglect (and notably body neglect) was associated more with postural than visual vertical tilts. These findings indicate that after RHS, an impaired verticality representation results from a kind of graviceptive neglect, bearing first on somaesthetic graviception and second on vestibular graviception. They also suggest that the human brain uses not only a mosaic of 2D representations but also 3D maps involving a transmodal representation of verticality.

Lower limb muscle strength of the affected side in stroke patients is an accurate predictor of the need for a KAFO

BACKGROUND

Accurate prediction of recovery is essential to determine whether a knee-ankle-foot orthosis (KAFO) is required in the subacute phase of stroke. However, there are currently no reliable methods to predict such recovery.

OBJECTIVE

This study aimed to determine whether muscle strength of the affected lower limb (affected side LL strength) in stroke patients in the subacute phase who cannot walk without a KAFO can be used to predict the continuous need for a KAFO, using a hand-held dynamometer.

METHODS

We enrolled patients with severe hemiplegia (n = 51) who were unable to walk without a KAFO for 10 days after stroke onset. They were divided into two groups depending on the continuous need for a KAFO at 1 month after onset; the KAFO and non-KAFO groups. Logistic regression analysis was used to investigate whether the affected side LL strength was a predictor of the continuous need for a KAFO at 1 month after onset. In addition, significant predictors were analyzed using receiver operating characteristic (ROC) curves.

RESULTS

The KAFO and non-KAFO groups included 23 (45.10%) and 28 (54.90%) patients, respectively. The affected side LL strength and pusher syndrome severity were identified as predictors of the continuous need for a KAFO. The predictor with the highest predictive ability was the affected side LL strength, with an area under the ROC curve of 0.80 (95% CI, 0.68-0.93).

CONCLUSIONS

Affected side LL strength may be a highly accurate predictor of the need for a KAFO in the subacute phase of stroke.

Efficacy of lateral truncal tilt training with a wedge on postural vertical and activities of daily living in recovery phase after stroke: A randomized crossover trial

BACKGROUND: The subjective postural vertical (SPV) is affected by training that requires participants to maintain balance; training to achieve sitting balance may also help SPV recovery and activities of daily living (ADLs). OBJECTIVE: This study aimed to assess the medium-term effects of balance training on the postural vertical (PV) and ADLs in patients with stroke. METHODS: Thirty-three patients with stroke were enrolled in this randomized crossover trial. The outcomes were SPV, SPV with eyes opened (SPV-EO), and the Functional Independent Measure (FIM) after the 14-day intervention of experimental or control training. Experimental training consisted of a maximum lateral truncal tilt to the paretic side at 0.25 Hz with or without a 10° wedge, repeated 60 times. Repeated-measures two-way analysis of variance was performed with two factors: intervention and the intervention period. RESULTS: There was no interaction between the control condition and the PV, but there was interaction between the intervention period and using a wedge for SPV variability errors. FIM showed an interaction between the intervention period and the use of a wedge. CONCLUSIONS: Balance training while sitting with a wedge significantly improved the SPV and FIM. This improved cognition and perception, which facilitate difficult dynamic tasks in ADLs.

Post-stroke lateropulsion terminology: pushing for agreement amongst experts

Post-stroke lateropulsion is prevalent. The global inconsistency in terminology used to describe the condition presents obstacles in accurately comparing research results, reaching consensus on use of measurement tools, agreeing upon a consistent approach to rehabilitation, and translating research to clinical practice. Commencing in 2021, 20 international experts undertook a Delphi Process that aimed to compile clinical practice recommendations for the rehabilitation of lateropulsion. As a part of the process, the panel agreed to aim to reach consensus regarding terminology used to describe the condition. Improved understanding of the condition could lead to improved management, which will enhance patient outcomes after stroke and increase efficiency of healthcare resource utilisation. While consensus was not reached, the panel achieved some agreement that 'lateropulsion' is the preferred term to describe the phenomenon of 'active pushing of the body across the midline toward the more affected side, and / or actively resisting weight shift toward the less affected side'. This group recommends that 'lateropulsion' is used in future research and in clinical practice.

Lateropulsion Prevalence after Stroke: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVES

Lateropulsion is a deficit of active body orientation with respect to gravity in the frontal plane, mostly observed after a stroke. It magnifies mobility limitations and so represents an emerging target in rehabilitation. Efforts to design specific interventional studies require some basic knowledge of epidemiology, which is insufficient today because many studies focused on a few severe forms in individuals called pushers. The objectives of this study were to bridge this gap.

METHODS

We systematically searched MEDLINE, EMBASE, CINAHL, and Cochrane Clinical Trials up to 31 May 2021 for original research reporting a prevalence or incidence of post-stroke lateropulsion. We followed MOOSE and PRISMA guidelines. Eligibility for inclusion, data extraction, and study quality (Joanna Briggs Institute guidelines) were evaluated by two reviewers who used a standardized protocol: PROSPERO (CRD42020175037). A random-effects meta-analysis was used to obtain the pooled prevalence, whose heterogeneity was investigated by subgroup analysis (stroke locations and post-stroke phases) and meta-regression.

RESULTS

We identified 22 studies (5125 individuals; mean age 68.5 years; 42.6% female; assessed 24 days, on average, after stroke), most published after 2000. The studies' quality was adequate, with only 8 (36.4%) showing risk of bias. The pooled lateropulsion prevalence was 55.1% (95% confidence interval [CI] [35.9-74.2]) and was consistent across assessment tools. After supratentorial stroke, lateropulsion prevalence was 41% (95%CI [33.5-48.5]), and only 12.5% (95%CI [9.2-15.9]) in individuals with severe lateropulsion, called pushers. Meta-regression did not reveal any effect of age, sex, geographic region, publication year, or study quality. Lateropulsion prevalence progressively decreased from 52.8% (95%CI [40.7-65]) in the acute phase to 37% (95%CI [26.3-47.7]) in the early subacute phase and 22.8% (95%CI [0-46.3]) in the late subacute phase. The ratio of right- to left-hemispheric stroke with lateropulsion increased as a function of time: 1.7 in the acute phase to 7.7 in the late subacute phase. After infratentorial stroke, lateropulsion prevalence was very high, reaching 83.2% (95%CI [63.9-100.3]).

CONCLUSIONS

Post-stroke lateropulsion prevalence is high, which appeals for its systematic detection to guide early interventions. Uprightness is predominantly controlled from the right hemisphere.

Watching the Effects of Gravity. Vestibular Cortex and the Neural Representation of "Visual" Gravity

Gravity is a physical constraint all terrestrial species have adapted to through evolution. Indeed, gravity effects are taken into account in many forms of interaction with the environment, from the seemingly simple task of maintaining balance to the complex motor skills performed by athletes and dancers. Graviceptors, primarily located in the vestibular otolith organs, feed the Central Nervous System with information related to the gravity acceleration vector. This information is integrated with signals from semicircular canals, vision, and proprioception in an ensemble of interconnected brain areas, including the vestibular nuclei, cerebellum, thalamus, insula, retroinsula, parietal operculum, and temporo-parietal junction, in the so-called vestibular network. Classical views consider this stage of multisensory integration as instrumental to sort out conflicting and/or ambiguous information from the incoming sensory signals. However, there is compelling evidence that it also contributes to an internal representation of gravity effects based on prior experience with the environment. This a priori knowledge could be engaged by various types of information, including sensory signals like the visual ones, which lack a direct correspondence with physical gravity. Indeed, the retinal accelerations elicited by gravitational motion in a visual scene are not invariant, but scale with viewing distance. Moreover, the "visual" gravity vector may not be aligned with physical gravity, as when we watch a scene on a tilted monitor or in weightlessness. This review will discuss experimental evidence from behavioral, neuroimaging (connectomics, fMRI, TMS), and patients' studies, supporting the idea that the internal model estimating the effects of gravity on visual objects is constructed by transforming the vestibular estimates of physical gravity, which are computed in the brainstem and cerebellum, into internalized estimates of virtual gravity, stored in the vestibular cortex. The integration of the internal model of gravity with visual and non-visual signals would take place at multiple levels in the cortex and might involve recurrent connections between early visual areas engaged in the analysis of spatio-temporal features of the visual stimuli and higher visual areas in temporo-parietal-insular regions.

Evaluation of subjective vertical perception among stroke patients: a systematic review

BACKGROUND

Verticality misperception is relatively common among patients after stroke, and it may be evaluated in terms of (a) subjective visual vertical (SVV), (b) subjective haptic vertical (SHV) and (c) subjective postural vertical (SPV). To better understand these assessment methods, we conducted a systematic review of the methodological characteristics of different protocols for evaluating SVV, SHV and SPV among individuals after stroke.

OBJECTIVE

To standardize the methodological characteristics of protocols for evaluating verticality perception after stroke.

METHODS

We searched the following databases: PUBMED, regional BVS portal (MEDLINE, LILACS, IBECS, CUBMED, Psychology Index and LIS), CINAHL, SCOPUS, Web of Science, Science Direct, Cochrane Library and PEDro. Two review authors independently used the QUADAS method (Quality Assessment of Diagnostic Accuracy Studies) and extracted data.

RESULTS

We included 21 studies in the review: most (80.9%) used SVV, eight (38.1%) used SPV and four (19.0%) used SHV. We observed high variability in assessments of verticality perception, due to patient positions, devices used, numbers of repetitions and angle of inclination for starting the tests.

CONCLUSION

This systematic review was one of the first to explore all the methods of assessing verticality perception after stroke, and it provides crucial information on how to perform the tests, in order to guide future researchers/clinicians.

Effects of prismatic adaptation on balance and postural disorders in patients with chronic right stroke: protocol for a multicentre double-blind randomised sham-controlled trial

INTRODUCTION

Patients with right stroke lesion have postural and balance disorders, including weight-bearing asymmetry, more pronounced than patients with left stroke lesion. Spatial cognition disorders post-stroke, such as misperceptions of subjective straight-ahead and subjective longitudinal body axis, are suspected to be involved in these postural and balance disorders. Prismatic adaptation has showed beneficial effects to reduce visuomotor disorders but also an expansion of effects on cognitive functions, including spatial cognition. Preliminary studies with a low level of evidence have suggested positive effects of prismatic adaptation on weight-bearing asymmetry and balance after stroke. The objective is to investigate the effects of this intervention on balance but also on postural disorders, subjective straight-ahead, longitudinal body axis and autonomy in patients with chronic right stroke lesion.

METHODS AND ANALYSIS

In this multicentre randomised double-blind sham-controlled trial, we will include 28 patients aged from 18 to 80 years, with a first right supratentorial stroke lesion at chronic stage (≥12 months) and having a bearing ≥60% of body weight on the right lower limb. Participants will be randomly assigned to the experimental group (performing pointing tasks while wearing glasses shifting optical axis of 10 degrees towards the right side) or to the control group (performing the same procedure while wearing neutral glasses without optical deviation). All participants will receive a 20 min daily session for 2 weeks in addition to conventional rehabilitation. The primary outcome will be the balance measured using the Berg Balance Scale. Secondary outcomes will include weight-bearing asymmetry and parameters of body sway during static posturographic assessments, as well as lateropulsion (measured using the Scale for Contraversive Pushing), subjective straight-ahead, longitudinal body axis and autonomy (measured using the Barthel Index).

ETHICS AND DISSEMINATION

The study has been approved by the ethical review board in France. Findings will be submitted to peer-reviewed journals relative to rehabilitation or stroke.

TRIAL REGISTRATION NUMBER

NCT03154138.

Spanish translation and validation of the Scale for Contraversive Pushing to measure pusher behaviour

INTRODUCTION

The aim of this study was to develop and validate a Spanish-language version of the Scale for Contraversive Pushing, used to diagnose and measure pusher behaviour in stroke patients.

METHODS

Translation-back translation was used to create the Spanish-language Scale for Contraversive Pushing; we subsequently evaluated its validity and reliability by administering it to a sample of patients. We also analysed its sensitivity to change in patients identified as pushers who received neurological physiotherapy.

RESULTS

Experts indicated that the content of the scale was valid. Internal consistency was very good (Cronbach's alpha of 0.94). The intraclass correlation coefficient showed high intra- and interobserver reliability (0.999 and 0.994, respectively). The Kappa and weighted Kappa coefficients were used to measure the reliability of each item; the majority obtained values above 0.9. Lastly, the differences between baseline and final evaluations of pushers were significant (paired sample t test), showing that the scale is sensitive to changes obtained through physical therapy.

CONCLUSIONS

The Spanish-language version of the Scale for Contraversive Pushing is valid and reliable for measuring pusher behaviour in stroke patients. In addition, it is able to evaluate the ongoing changes in patients who have received physical therapy.

Case Report: Visual Deprivation in Pusher Syndrome Complicated by Hemispatial Neglect After Basal Ganglia Stroke

We aimed to explore whether motor function and activities of daily life (ADL) could be improved with the application of visual deprivation in two patients with Pusher syndrome complicated by hemispatial neglect after right basal ganglia stroke. We assessed two stroke patients suffering from severe motor disturbances, both tilting heavily to the left, with diagnoses of Pusher syndrome and left hemispatial neglect. Vision in the left eye was deprived using patches during clinical rehabilitation. Motor function promotion was confirmed using the Burke Lateropulsion Scale (BLS), Fugl–Meyer Balance Scale (FMBS), and Holden grade (HG), while the Barthel index (BI) assessed ADL immediately and 1 week after intervention. Both patients regained standing balance immediately using visual deprivation, as well as walking ability, although both scored 0 on the FMBS and HG. After 1 week of treatment, one patient increased to 11 and 3 on the FMBS and HG, respectively, while the BLS score decreased from 12 to 2, and the ADL increased from 23 to 70. The other patient demonstrated increases to 10 and 3 on the FMBS and HG, respectively, with the BLS decreasing from 13 to 3, and the ADL increasing from 25 to 60. Therefore, in the rehabilitation treatment of Pusher syndrome complicated by hemispatial neglect due to basal ganglia stroke, visual deprivation can significantly improve motor function and shorten the treatment course.

Effects of dynamic supported standing training in a patient with pusher behavior: a case report

BACKGROUND

The effects of task-specific and voluntary exercise in upright positions for pusher behavior remain unclear. In this report, we aimed to describe the effects of dynamic supported standing training using a modified standing frame to correct the alignment in a patient with severe pusher behavior.

CASE DESCRIPTION

A 76-year-old man with cardioembolic ischemic stroke demonstrated pusher behavior. The patient underwent 3 days of dynamic supported standing training using a modified standing frame. The Scale for Contraversive Pushing, the Burke Lateropulsion Scale, and the Trunk Control Test were used to assess changes.

OUTCOMES

Immediate improvements in sitting balance were observed after the intervention, and the effects persisted to 8 days later.

CONCLUSION

Dynamic supported standing training using a modified standing frame may improve pusher behavior with short-term training. The collapsed posture of the patient in the present case was corrected using the modified standing frame. This neutral standing position could have a positive effect on motor learning with respect to holding one's posture.

Scale for contraversive pushing in stroke patients: pusher behavior vs Thalamic astasia differential diagnosis and psychometric properties

BACKGROUND

: Few studies have investigated the psychometric properties of the Scale for Contraversive Pushing (SCP) in depth, and none have evaluated its ability to establish differential diagnosis between pusher behavior (PB) and thalamic astasia (TA).

OBJECTIVES

: To study the ability of the SCP to establish differential diagnosis, its reliability, content, construct, and internal validity in the assessment of subacute stroke patients.

METHODS

: 120 individuals were evaluated using the SCP over a four-week period of treatment. Intra- and inter-observer reliability, floor and ceiling effects, minimum detectable change (MDC), internal validity and sensitivity to change were explored. In addition, the Barthel Index and the Trunk Control Test were used to study their correlations with the SCP.

RESULTS

: Discriminant validity provides evidence that the correlation between SCP items was large or moderate. Convergent validity demonstrated that the correlation of each item with the total score of the scale was high (at around 0.8). Sensitivity to change was large (W = 0.274). Intra- and inter-observer reliability were excellent (Intraclass Correlation Coefficient > 0.9; k > 0.8), except for items B standing and C sitting (k > 0.7). The MDC was 1.39, and ceiling (8.333%) and floor (15.833%) effects were adequate. Cronbach's alpha (α) was equal to 0.901 (0.874-0.924) and McDonald's Omega (ω) was equal to 0.883 (0.856-0.973), showing excellent internal consistency.

CONCLUSIONS

: The SCP is a reliable and valid tool which can successfully establish differential diagnosis between PB and TA and evaluate the changes generated by physiotherapy treatment.

Use of transcranial direct current stimulation in poststroke postural imbalance

Independent gait following stroke is ultimate goal of rehabilitation. Non-invasive neuromodulation achieving it has never been reported. A 74-year-old woman suffered from subarachnoid haemorrhage, followed by hydrocephalus. Both were treated successfully. Even 1 year after the ictus, ambulation was difficult due to truncal instability with lateropulsion mainly to the left side. Transcranial direct current stimulation (tDCS) was applied to the parietal area (2mA for 20 min/day; anode on left side, cathode on right) for 16 days. The intervention improved her truncal instability and she achieved independent gait. tDCS of the parietal area could be a novel treatment option for gait disturbance due to postural instability following stroke.

Multisensory contribution in visuospatial orientation: an interaction between neck and trunk proprioception

A coherent perception of spatial orientation is key in maintaining postural control. To achieve this the brain must access sensory inputs encoding both the body and the head position and integrate them with incoming visual information. Here we isolated the contribution of proprioception to verticality perception and further investigated whether changing the body position without moving the head can modulate visual dependence-the extent to which an individual relies on visual cues for spatial orientation. Spatial orientation was measured in ten healthy individuals [6 female; 25-47 years (SD 7.8 years)] using a virtual reality based subjective visual vertical (SVV) task. Individuals aligned an arrow to their perceived gravitational vertical, initially against a static black background (10 trials), and then in other conditions with clockwise and counterclockwise background rotations (each 10 trials). In all conditions, subjects were seated first in the upright position, then with trunk tilted 20° to the right, followed by 20° to the left while the head was always aligned vertically. The SVV error was modulated by the trunk position, and it was greater when the trunk was tilted to the left compared to right or upright trunk positions (p < 0.001). Likewise, background rotation had an effect on SVV errors as these were greater with counterclockwise visual rotation compared to static background and clockwise roll motion (p < 0.001). Our results show that the interaction between neck and trunk proprioception can modulate how visual inputs affect spatial orientation.

Lateropulsion After Hemispheric Stroke: A Form of Spatial Neglect Involving Graviception

OBJECTIVE

To test the hypothesis that lateropulsion is an entity expressing an impaired body orientation with respect to gravity in relation to a biased graviception and spatial neglect.

METHODS

Data from the DOBRAS cohort (ClinicalTrials.gov: NCT03203109) were collected 30 days after a first hemisphere stroke. Lateral body tilt, pushing, and resistance were assessed with the Scale for Contraversive Pushing.

RESULTS

Among 220 individuals, 72% were upright and 28% showed lateropulsion (tilters [14%] less severe than pushers [14%]). The 3 signs had very high factor loadings (>0.90) on a same dimension, demonstrating that lateropulsion was effectively an entity comprising body tilt (cardinal sign), pushing, and resistance. The factorial analyses also showed that lateropulsion was inseparable from the visual vertical (VV), a criterion referring to vertical orientation (graviception). Contralesional VV biases were frequent (44%), with a magnitude related to lateropulsion severity: upright -0.6° (-2.9; 2.4), tilters -2.9° (-7; 0.8), and pushers -12.3° (-15.4; -8.5). Ipsilesional VV biases were less frequent and milder (p < 0.001). They did not deal with graviception, 84% being found in upright individuals. Multivariate, factorial, contingency, and prediction analyses congruently showed strong similarities between lateropulsion and spatial neglect, the latter encompassing the former.

CONCLUSIONS

Lateropulsion (pusher syndrome) is a trinity constituted by body tilt, pushing, and resistance. It is a way to adjust the body orientation in the roll plane to a wrong reference of verticality. Referring to straight above, lateropulsion might correspond to a form of spatial neglect (referring to straight ahead), which would advocate for 3D maps in the human brain involving the internal model of verticality.

Is Lateropulsion Really Related with a Specific Lesion of the Brain?

Lateropulsion (pusher syndrome) is an important barrier to standing and gait after stroke. Although several studies have attempted to elucidate the relationship between brain lesions and lateropulsion, the effects of specific brain lesions on the development of lateropulsion remain unclear. Thus, the present study investigated the effects of stroke lesion location and size on lateropulsion in right hemisphere stroke patients. The present retrospective cross-sectional observational study assessed 50 right hemisphere stroke patients. Lateropulsion was diagnosed and evaluated using the Scale for Contraversive Pushing (SCP). Voxel-based lesion symptom mapping (VLSM) analysis with 3T-MRI was used to identify the culprit lesion for SCP. We also performed VLSM controlling for lesion volume as a nuisance covariate, in a multivariate model that also controlled for other factors contributing to pusher behavior. VLSM, combined with statistical non-parametric mapping (SnPM), identified the specific region with SCP. Lesion size was associated with lateropulsion. The precentral gyrus, postcentral gyrus, inferior frontal gyrus, insula and subgyral parietal lobe of the right hemisphere seemed to be associated with the lateropulsion; however, after adjusting for lesion volume as a nuisance covariate, no lesion areas were associated with the SCP scores. The size of the right hemisphere lesion was the only factor most strongly associated with lateropulsion in patients with stroke. These results may be useful for planning rehabilitation strategies of restoring vertical posture and understanding the pathophysiology of lateropulsion in stroke patients.

The association between contraversive lateropulsion and outcomes post stroke: A systematic review

Background: Contraversive lateropulsion is a common post-stroke impairment. Rehabilitation outcomes in stroke survivors exhibiting lateropulsion may differ from those without lateropulsion.Objectives: To systematically review evidence regarding associations between:1. Presence/severity of lateropulsion after stroke and functional outcome, rehabilitation length of stay, and discharge destination;2. Stroke-related factors and resolution of lateropulsion, functional outcome, rehabilitation length of stay, and discharge destination in affected stroke survivors.Methods: Medline, CINAHL, and Embase databases were searched. Journal articles published in English reporting on resolution of lateropulsion, length of stay, functional outcome, and/or discharge destination associated with post-stroke lateropulsion were included for review. Studies that did not include a comparison group (stroke survivors without lateropulsion, or sub-groups of participants with lateropulsion based on stroke-related factors), animal studies, and studies reporting only on ipsiversive lateropulsion and/or lateral medullary syndrome were excluded. Two authors independently assessed studies for inclusion. Included studies were evaluated using the Risk of Bias Assessment Tool for Nonrandomized Studies.Results: Screening identified 133 articles. Seven articles met inclusion criteria. People with contraversive lateropulsion after stroke can achieve similar improvements in function as those without lateropulsion, increasing likelihood of discharge home, but require longer rehabilitation durations to do so.Conclusions: The finding that longer rehabilitation durations are required for people with post-stroke lateropulsion to achieve their functional potential and increase likelihood of discharge home has implications for resourcing rehabilitation services. Given an additional three to four weeks in rehabilitation, people with post-stroke lateropulsion can achieve functional improvements function similar to those without lateropulsion.

Postural Assessment Scale for Stroke Patients in Acute, Subacute and Chronic Stage: A Construct Validity Study

(1) Background: Observational scales are the most common methodology used to assess postural control and balance in people with stroke. The aim of this paper was to analyse the construct validity of the Postural Assessment Scale for Stroke Patients (PASS) scale in post-stroke patients in the acute, subacute, and chronic stroke phases. (2) Methods: Sixty-one post-stroke participants were enrolled. To analyze the construct validity of the PASS, the following scales were used: the Functional Ambulatory Category (FAC), the Wisconsin Gait Scale (WGS), the Barthel Index (BI) and the Functional Independence Measure (FIM). (3) Results: The construct validity of the PASS scale in patients with stroke at acute phase was moderate with the FAC (r = −0.791), WGS (r = −0.646) and FIM (r = −0.678) and excellent with the BI (r = 0.801). At subacute stage, the construct validity of the PASS scale was excellent with the FAC (r = 0.897), WGS (r = −0.847), FIM (r = −0.810) and BI (r = −0.888). At 6 and 12 months, the construct validity of the PASS with the FAC, WGS, FIM and BI was also excellent. (4) Conclusions: The PASS scale is a valid instrument to assess balance in post-stroke individuals especially, in the subacute and chronic phases (at 6 and 12 months).

Multisensory Interactions in Head and Body Centered Perception of Verticality

Percepts of verticality are thought to be constructed as a weighted average of multisensory inputs, but the observed weights differ considerably between studies. In the present study, we evaluate whether this can be explained by differences in how visual, somatosensory and proprioceptive cues contribute to representations of the Head In Space (HIS) and Body In Space (BIS). Participants (10) were standing on a force plate on top of a motion platform while wearing a visualization device that allowed us to artificially tilt their visual surroundings. They were presented with (in)congruent combinations of visual, platform, and head tilt, and performed Rod & Frame Test (RFT) and Subjective Postural Vertical (SPV) tasks. We also recorded postural responses to evaluate the relation between perception and balance. The perception data shows that body tilt, head tilt, and visual tilt affect the HIS and BIS in both experimental tasks. For the RFT task, visual tilt induced considerable biases (≈ 10° for 36° visual tilt) in the direction of the vertical expressed in the visual scene; for the SPV task, participants also adjusted platform tilt to correct for illusory body tilt induced by the visual stimuli, but effects were much smaller (≈ 0.25°). Likewise, postural data from the SPV task indicate participants slightly shifted their weight to counteract visual tilt (0.3° for 36° visual tilt). The data reveal a striking dissociation of visual effects between the two tasks. We find that the data can be explained well using a model where percepts of the HIS and BIS are constructed from direct signals from head and body sensors, respectively, and indirect signals based on body and head signals but corrected for perceived neck tilt. These findings show that perception of the HIS and BIS derive from the same sensory signals, but see profoundly different weighting factors. We conclude that observations of different weightings between studies likely result from querying of distinct latent constructs referenced to the body or head in space.

Effects of performing a lateral-reaching exercise while seated on a tilted surface for severe post-stroke pusher behavior: A case series

Background: For patients with severe post-stroke pusher behavior (PB), acquiring a vertical posture involves correcting paretic-sided body tilt to the non-paretic side. Active lateral sitting training may facilitate improvement in postural orientation for patients with PB. However, its effect on patients with severe PB remains unclear.Objective: To determine the effect of performing a lateral-reaching exercise in patients with severe PB seated on a tilted surfaceMethods: Three patients with severe PB due to right hemispheric stroke participated in our study. Using a single-case design, the intervention's effect was verified using the applied behavior analysis method. Conventional physical therapy was performed for 1 h at baseline and at follow-up. During the intervention, lateral sitting training on a tilted surface was performed 40 times per session (total, 2 sessions). PB was assessed using the Scale for Contraversive Pushing and the Burke Lateropulsion Scale, and patient-reported fear of falling. The Function in Sitting Test (FIST) and the Trunk Control Test (TCT) were administered.Results: PB improved in all patients post-intervention and persisted at follow-up. Fear of falling during the passive sitting task while moving toward the non-paretic side disappeared post-intervention and at follow-up. FIST and TCT scores improved in 2 patients.Conclusion: The lateral sitting exercise reduced severe PB in all patients; however, sitting balance and trunk performance did not improve in 1 patient. Future studies to examine the adaptability of this task and long-term effects are needed.

Comparison of two methods based on one psychophysical paradigm to measure the subjective postural vertical in standing

The perception of verticality can be altered with age or due to neurological diseases. Different procedures have been described to measure the subjective postural vertical (SPV). A deviation from the earth vertical was either described as a single position or as a sector defined by two positions representing the edges of the perceived verticality. In this study, for the first time, we investigated if these two methods produce equal values, and consequently can be merged to set normative values. SPV in standing was tested in 24 healthy young adults (28.4 (5.2) years of age, 12 women). Each participant performed both methods in the sagittal and the frontal plane. Absolute and constant error values were found to be similar for both methods in both planes with a mean difference of less than 0.3° (p > 0.148). The mean width of the SPV sector was 3.9° (0.9°) in the sagittal and 3.7° (1.4°) in the frontal plane, ranging in the mean from -5.5° to 8.1° in the sagittal and -5.3° to 4.3° in the frontal plane. SPV values significantly differed in range between both methods in both planes with a mean difference of more than 3.1° (p<0.002). Results show that both methods, SPVposition and SPVsector, produce equal error values when applied with otherwise similar methodological settings and can therefore be used alternatively or within the same meta-analysis. The SPVsector, however, led to wider range values and was less frequently rated as the preferred method to represent the participants' subjective verticality.

Balance, Lateropulsion, and Gait Disorders in Subacute Stroke

OBJECTIVE

To test the hypothesis that impaired body orientation with respect to gravity (lateropulsion) would play a key role in poststroke balance and gait disorders.

METHODS

Cohort study of 220 individuals consecutively admitted to a neurorehabilitation ward after a first hemisphere stroke (DOBRAS cohort [Determinants of Balance Recovery After Stroke] 2012-2018, ClinicalTrials.gov: NCT03203109), with clinical data systematically collected at 1 month, then at discharge. Primary outcomes were balance and gait disorders, quantified by the Postural Assessment Scale for Stroke and the modified Fugl-Meyer Gait Assessment, to be explained by all deficits on day 30, including lateropulsion assessed with the Scale for Contraversive Pushing. Statistics comprised linear regression analysis, univariate and multivariate analyses, and receiver operating characteristic curves.

RESULTS

Lateropulsion was frequent, especially after right hemisphere stroke (RHS, D30, 48%; discharge 24%), almost always in right-handers. Among all deficits, impaired body orientation (lateropulsion) had the most detrimental effect on balance and gait. After RHS, balance disorders were proportional to lateropulsion severity, which alone explained almost all balance disorders at initial assessment (90%; 95% confidence interval [CI] [86-94], p < 0.001) and at discharge (92%; 95% CI 89-95, p < 0.001) and also the greatest part of gait disorders at initial assessment (66%; 95% CI 56-77, p < 0.001) and at discharge (68%; 95% CI 57-78, p < 0.001).

CONCLUSION

Lateropulsion is the primary factor altering poststroke balance and gait at the subacute stage and therefore should be systematically assessed. Poststroke balance and gait rehabilitation should incorporate techniques devoted to misorientation with respect to gravity.

Factors Influencing Sitting Ability During the Acute Post-Stroke Phase: A Multicenter Prospective Cohort Study in Japan

OBJECTIVES

Sitting ability during the acute phase after stroke is a useful indicator of functional outcomes; however, factors that affect this ability have not been evaluated. Therefore, this study aimed to identify and evaluate factors that affect sitting ability in the acute phase after stroke.

MATERIALS AND METHODS

This multicenter prospective cohort study included hemispheric stroke patients who underwent an inpatient rehabilitation program after acute stroke from five acute care hospitals. The effect of age, sex, lesion side, etiology, consciousness disorder, stroke and dementia history, stroke-related complications, National Institutes of Health Stroke Scale score, hemiparalysis, turn-over movement from the supine position and sit-up movement, and Scale for Contraversive Pushing on the "remain sitting" item in the revised version of the Ability of Basic Movement Scale at the time of acute hospital discharge were investigated. Factors affecting sitting ability were identified using binomial logistic regression analysis.

RESULTS

We included 293 stroke patients. Age (odds ratio: 0.943, 95% confidence interval: 0.910-0.977, p=0.001), National Institutes of Health Stroke Scale score (odds ratio: 0.862, 95% confidence interval: 0.811-0.916, p<0.001), and Scale for Contraversive Pushing score (odds ratio: 0.543, 95% confidence interval: 0.419-0.705, p<0.001) were identified as independent predictors of sitting ability at the time of hospital discharge (median; 23.0 days).

CONCLUSIONS

Older patients and those with high Scale for Contraversive Pushing and National Institutes of Health Stroke Scale scores experienced difficulties in regaining sitting ability. These results may guide physical therapy for patients with impaired sitting ability due to hemispheric stroke.

Subjective postural vertical in Parkinson's disease with lateral trunk flexion

BACKGROUND

Patients with Parkinson's disease (PD) and associated lateral trunk flexion (LTF) cannot accurately perceive their own verticality.

OBJECTIVE

We measured the subjective postural vertical in coronal plane (SPVc) angle on patients' ipsilateral and contralateral sides and combined to clarify the effects of SPVc on LTF. We also investigated effects of the SPVc angle on LTF severity.

METHODS

Thirty-nine patients (aged 74.1 ± 7.6 years) were divided between those with mild LTF (LTF angle < 10°, n = 34) and those with moderate to severe LTF (LTF angle ≥ 10°, n = 5) for comparison of the LTF angle, SPVc angle on both sides, inter-measurement variation in the SPVc angle, and the LTF to SPVc angle ratio (SPVc ratio).

RESULTS

We found significant positive correlation between LTF and the SPVc angle on the combined (r = .54, P = .001), ipsilateral (r = .51, P = .002), and contralateral (r = .50, P = .002) sides. We found significant negative correlation between the LTF angle and the SPVc ratio on the combined SPVc (r = -.82, P = .001), ipsilateral (r = -.69, P = .001), and contralateral (r = -.75, P = .001) sides and between the LTF and ipsilateral side coefficient of variation (r = -.34, P = .038). SPVc angles on ipsilateral and contralateral sides were significantly greater in cases of moderate to severe LTF than in cases of mild LTF (P < .01).

CONCLUSIONS

Subjective postural vertical in coronal plane assessment may be useful for assessing patients with PD and associated LTF.

Starting position effects in the measurement of the postural vertical for pusher behavior

Pusher behavior (PB) is a severe lateral postural disorder that involves a disturbed subjective postural vertical (SPV) in the frontal plane. SPV is measured by determining the mean value and standard deviation of several trials beginning on both the contralesional- and ipsilesional-tilted positions. However, the postural representation, when passively tilted to the contralesional versus ipsilesional position, is different between patients with and without PB. Therefore, we hypothesized that SPV dependence on the starting position will be influenced by PB. For 53 patients with hemispheric stroke enrolled, SPV was measured using a non-motorized vertical board with eyes closed. The mean value (tilt direction) and standard deviation (variability) were calculated in four trials, each from two positions, with the patient tilted to the contralesional position (SPV-CL condition) and then to the ipsilesional position (SPV-IL condition). Patients were categorized into the non-pusher (n = 29) and pusher (n = 24) groups. In the SPV-CL trials, the tilt direction was significantly tilted contralesionally for the pusher group (- 6.3° ± 1.6°) compared with that for the non-pusher group (- 2.2° ± 1.8°; p < 0.001), with no significant difference in variability between the groups. In the SPV-IL trials, the tilt direction was not significantly different between the groups, but the variability was significantly higher in the pusher group (4.8° ± 2.0°) than in the non-pusher group (2.2° ± 1.3°; p < 0.001). The dependence of tilt direction and variability of SPV on the starting position in patients with PB differed from those noted in patients without PB. These results may help explain this abnormal posture and optimize neurological rehabilitation strategies for PB.

Rasch analysis of the Burke Lateropulsion Scale (BLS)

BACKGROUND

Lateropulsion is a common problem following stroke. Whilst the Burke Lateropulsion Scale (BLS) is recommended in the literature as the outcome measure of choice for measuring lateropulsion, the internal validity of the BLS has not been investigated.

OBJECTIVES

To evaluate the internal validity of the BLS for use in evaluating the effectiveness of therapies aimed at reducing lateropulsion.

METHODS

Rasch analysis procedures were undertaken including assessment of overall model fit, item, and person fit, threshold ordering, differential item functioning, internal consistency, targeting, and dimensionality.

RESULTS

Data from 132 participants were utilized to perform Rasch analysis of the BLS. In this preliminary study, overall model fit and individual item and person fit were found to be good using fit residual statistics and chi-square probability values. The BLS was found to be unidimensional and have good internal consistency (Person Separation Index 0.867). Thresholds for four of the five items were found to be only marginally disordered and were subsequently not modified. Non-uniform differential item functioning was detected for age for the transfers item; however, this item did not display item misfit and was therefore not removed.

CONCLUSIONS

This study identified good psychometric properties of the BLS using Rasch analysis and supports the use of the BLS as a measure of lateropulsion following stroke. Further use of Rasch analysis on the BLS using a larger sample is recommended to confirm these preliminary findings and allow transformation into an interval-level scale.

Role of diffusion tensor imaging in analyzing the neural connectivity of the parieto-insular vestibular cortex in pusher syndrome: As case report

RATIONALE

Pusher syndrome is a disorder of postural control. It is associated with unilateral lesions on central vestibular system. In the current study, we attempted to identify and investigate neural connectivity of the parieto-insular vestibular cortex in a patient with pusher syndrome, using diffusion tensor imaging.

PATIENT CONCERNS

A 60-year-old male patient had left hemiplegia due to an infarction on right premotor cortex, primary motor cortex, corona radiata and temporal and occipital lobe. The patient had severe motor weakness in left upper and lower limb, left side neglect and significant pusher syndrome.

DIAGNOSIS

Patient was diagnosed with left hemiplegia due to an infarction in the right middle cerebral artery territory at the neurology department of a university hospital.

INTERVENTIONS

One patient and 5 control subjects of similar age participated. Diffusion tensor imaging data were acquired at 4-month and 12-month after the initial injury.

OUTCOMES

Fractional anisotropy, mean diffusivity, and tract volume (TV) were measured. TV values in both affected and unaffected hemispheres of the patient were significantly decreased at 4-month compared to those of control subjects. In the unaffected hemisphere of the patient, TV value showed significant increase at 12-month compared to that at 4-month. Although the TV value at 12-month of the affected hemisphere was out of reference range, TV was considerably increased compared to that at 4-month. Mean values for fractional anisotropy or mean diffusivity in 2 hemispheres did not show significant difference compared to those of control subjects regardless of month.

LESSONS

Restoration of an injured projection pathway between the vestibular nuclei and parieto-insular vestibular cortex with recovery of pusher syndrome was found in a patient with stroke.

Novel characterization of subjective visual vertical in patients with unilateral spatial neglect

Visual vertical (VV), visually perceived direction of gravity, is widely measured to assess the vestibular function and visuospatial cognition. VV has been assessed by comparing orientation and variability of measured values separately between subject groups. However, changes in orientation and variability often differ in patients with unilateral spatial neglect (USN). Here, we developed a novel classification of VV that combines orientation and variability and characterized the effects of USN on VV. Forty-three subacute stroke patients with or without USN (USN+, n = 17; USN-, n = 26) and 33 age-matched controls were included in the study. In darkness, a luminous line, initially tilted at 30° either to the left or right, gradually rotated towards the vertical. The VV was defined as the deviation of the subjectively-perceived vertical from the true vertical. The new classification demonstrated that, while the majority of USN + patients (14/17) exhibited large variability, nine showed normal orientation and five showed greater contra-lesional deviation of orientation, suggesting different underlying mechanisms for orientation and variability. Further analyses revealed VV deviation to the initial tilt in all groups. However, the deviation in USN + was larger and more variable, indicating attentional disorders. Such characterization would contribute to individually specified clinical rehabilitation.

Electromyography-guided electrical stimulation therapy for patients with pusher behavior: A case series

BACKGROUND

Pusher behavior (PB) is a posture disorder due to a subjective bias in verticality perception. However, muscle activity characteristics in this disorder and the effective treatments are not known.

OBJECTIVE

To investigate electromyographic (EMG) activity and the effect of electrical stimulation (ES) in PB.

METHODS

Two PB patients were enrolled. The EMG activity was measured over the upper and lower limb muscles on the non-paretic side, and over the trunk muscles on both sides during sitting. We used a modified ABA single-case design consisting of consecutive baseline, intervention, and follow-up, each phase lasting 2 d. During the intervention, together with conventional treatment, the patient received ES for 5 min/d on the muscle antagonist to the muscle where excessive activity was observed. PB was assessed before and after each phase using the scale for contraversive pushing and the Burke lateropulsion scale. Truncal balance was evaluated using the trunk control test.

RESULTS

In both patients, electromyography of the non-paretic triceps brachii muscle revealed excessive activity. To inhibit the excessive activity, ES was applied to the non-paretic biceps muscle. All scores improved after the intervention and follow-up phases.

CONCLUSION

ES based on EMG activity is therapeutic for PB.

Effects of diagonally aligned sitting training with a tilted surface on sitting balance for low sitting performance in the early phase after stroke: a randomised controlled trial

PURPOSE

To clarify the effects of diagonally aligned sitting training using a tilted surface on sitting balance for patients with low sitting performance in the early phase after stroke.

MATERIALS AND METHODS

This was an assessor-blinded randomised controlled trial. The experimental group used a surface tilted 10° backward and down toward the most affected side; the control group trained on a horizontal surface. Both groups were asked to move their trunk diagonally forward toward the least affected side. Participants performed the activity 40 times/session for seven sessions over 8 days. Sitting performances were assessed using the function in sitting test (FIST), subjective postural vertical (SPV) on the diagonal plane, and trunk impairment scale (TIS).

RESULTS

Thirty-three stroke patients were randomly allocated into two groups. Treatment effects differed significantly: mean differences between groups for FIST (total score, static, dynamic, scooting, and reactive) were 8.96, 2.35, 3.01, 1.27, and 1.72 points, for the mean SPV value was 1.82°, and for the TIS (total score and static) were 1.87 and 1.58 points, respectively. These results were more favourable in the experimental group.

CONCLUSIONS

Diagonally aligned sitting training on a tilted surface improves sitting balance and modulates the SPV compared with a horizontal surface.