Latent disconnectome prediction of long-term cognitive-behavioural symptoms in stroke.

Stroke significantly impacts the quality of life. However, the long-term cognitive evolution in stroke is poorly predictable at the individual level. There is an urgent need to better predict long-term symptoms based on acute clinical neuroimaging data. Previous works have demonstrated a strong relationship between the location of white matter disconnections and clinical symptoms. However, rendering the entire space of possible disconnection-deficit associations optimally surveyable will allow for a systematic association between brain disconnections and cognitive-behavioural measures at the individual level. Here we present the most comprehensive framework, a composite morphospace of white matter disconnections (disconnectome) to predict neuropsychological scores 1 year after stroke. Linking the latent disconnectome morphospace to neuropsychological outcomes yields biological insights that are available as the first comprehensive atlas of disconnectome-deficit relations across 86 scores-a Neuropsychological White Matter Atlas. Our novel predictive framework, the Disconnectome Symptoms Discoverer, achieved better predictivity performances than six other models, including functional disconnection, lesion topology and volume modelling. Out-of-sample prediction derived from this atlas presented a mean absolute error below 20% and allowed personalize neuropsychological predictions. Prediction on an external cohort achieved an R2 = 0.201 for semantic fluency. In addition, training and testing were replicated on two external cohorts achieving an R2 = 0.18 for visuospatial performance. This framework is available as an interactive web application (http://disconnectomestudio.bcblab.com) to provide the foundations for a new and practical approach to modelling cognition in stroke. We hope our atlas and web application will help to reduce the burden of cognitive deficits on patients, their families and wider society while also helping to tailor future personalized treatment programmes and discover new targets for treatments. We expect our framework's range of assessments and predictive power to increase even further through future crowdsourcing.

Clinical practice recommendations for management of lateropulsion after stroke determined by a Delphi expert panel.

OBJECTIVE: People exhibiting post-stroke lateropulsion actively push their body across the midline to the more affected side and/or resist weight shift toward the less affected side. Despite its prevalence and associated negative rehabilitation outcomes, no clinical practice guidelines exist for the rehabilitation of post-stroke lateropulsion. We aimed to develop consensus-based clinical practice recommendations for managing post-stroke lateropulsion using an international expert panel. DESIGN: This Delphi panel process conformed with Guidance on Conducting and Reporting Delphi Studies recommendations. PARTICIPANTS: Panel members had demonstrated clinical and/or scientific background in the rehabilitation of people with post-stroke lateropulsion. MAIN MEASURES: The process consisted of four electronic survey rounds. Round One consisted of 13 open questions. Subsequent rounds ascertained levels of agreement with statements derived from Round One. Consensus was defined a priori as ≥75% agreement (agree or strongly agree), or ≥70% agreement after excluding 'unsure' responses. RESULTS: Twenty participants completed all four rounds. Consensus was achieved regarding a total of 119 recommendations for rehabilitation approaches and considerations for rehabilitation delivery, positioning, managing fear of falling and fatigue, optimal therapy dose, and discharge planning. Statements for which 'some agreement' (50%-74% agreement) was achieved and those for which recommendations remain to be clarified were recorded. CONCLUSIONS: These recommendations build on existing evidence to guide the selection of interventions for post-stroke lateropulsion. Future research is required to elaborate specific rehabilitation strategies, consider the impact of additional cognitive and perceptual impairments, describe positioning options, and detail optimal therapy dose for people with lateropulsion.

Speech rehabilitation in post-stroke aphasia using visual illustration of speech articulators: A case report study.

Recent studies on the remediation of speech disorders suggest that providing visual information of speech articulators may contribute to improve speech production. In this study, we evaluate the effectiveness of an illustration-based rehabilitation method on speech recovery of a patient with non-fluent chronic aphasia. The Ultraspeech-player software allowed visualization by the patient of reference tongue and lip movements recorded using ultrasound and video imaging. This method can improve the patient's awareness of their own lingual and labial movements, which can increase the ability to coordinate and combine articulatory gestures. The effects of this method were assessed by analyzing performance during speech tasks, the phonological processes identified in the errors made during the phoneme repetition task and the acoustic parameters derived from the speech signal. We also evaluated cognitive performance before and after rehabilitation. The integrity of visuospatial ability, short-term and working memory and some executive functions supports the effectiveness of the rehabilitation method. Our results showed that illustration-based rehabilitation technique had a beneficial effect on the patient's speech production, especially for stop and fricative consonants which are targeted (high visibility of speech articulator configurations) by the software, but also on reading abilities. Acoustic parameters indicated an improvement in the distinction between consonant categories: voiced and voiceless stops or alveolar, post-alveolar and labiodental fricatives. However, the patient showed little improvement for vowels. These results confirmed the advantage of using illustration-based rehabilitation technique and the necessity of detailed subjective and objective intra-speaker evaluation in speech production to fully evaluate speech abilities.

Inter- and Intra-Rater Reliability of the Visual Vertical in Subacute Stroke.

BACKGROUND AND PURPOSE: Visual vertical (VV) has been used increasingly as a routine clinical assessment to identify alteration of verticality perception as a possible cause of postural disorders after stroke. This study aims to determine whether the reliability of VV is sufficient to support a wide clinical use in neurorehabilitation for monitoring of patients with stroke. METHODS: Twenty patients with subacute stroke in neurorehabilitation unit were tested after a first and unique hemispheric stroke. To evaluate the inter-rater reliability, VV was assessed the same day by 2 examiners whose degrees of expertise differed. The second examiner repeated the test the next day to investigate intrarater reliability. VV orientation (mean, primary criterion) and uncertainty (SD, secondary criterion) were calculated for 10 trials. Their reliability was quantified by the intraclass correlation coefficient, Bland-Altman plots, and the minimal detectable change. The concordance between 2 examiners was quantified by Cohen's κ coefficients (κ). RESULTS: About VV orientation, inter- and intrarater reliability were excellent (intraclass correlation coefficient, 0.979 and 0.982). The Bland-Altman plots and the minimal detectable change revealed a difference inferior to 2° between 2 tests. The concordance between 2 assessments for the diagnosis of abnormal VV orientation was absolute for the same examiner (κ=1; P<0.05) and excellent between 2 examiners (κ=0.92; P<0.05). As for VV uncertainty the intrarater reliability was satisfactory (intraclass correlation coefficient, 0.836) but the inter-rater reliability was poor (intraclass correlation coefficient, 0.211). CONCLUSIONS: The orientation of the VV is a highly reliable criterion, which may be used both in research and in routine clinical practice.

The pathogenesis of Pisa syndrome in Parkinson's disease.

Postural abnormalities such as postural deviations affect nearly all patients with advanced Parkinson's disease and represent an important source of disability. Although their existence has long been known, their management remains a challenge as they respond poorly to medication, brain surgery, or physiotherapy. Improving management strategies will require better understanding of the mechanisms underlying such postural deformities. In this review on the pathophysiology of Pisa syndrome, we examine the data supporting the central and peripheral hypotheses that attempt to explain these lateral trunk deviations. Although the pathophysiology is very probably multifactorial, the bulk of the data supports central, rather than peripheral, hypotheses. The central hypotheses that are best supported by both animal studies and clinical data include asymmetry of basal ganglia output and abnormalities in the central integration of sensory information. Further studies are needed to elucidate the pathophysiology underlying Pisa syndrome.

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.

Determining an optimal posturography dataset to identify standing behaviors in the post-stroke subacute phase. Cross-sectional study.

BACKGROUND: A key issue for posturography is the expression of robust results, in a simplified way. Most studies of individuals post-stroke concern the chronic phase, with small sample sizes. OBJECTIVES: By reducing the number of posturographic indices, we aimed to determine an optimal dataset and understand typical postural behaviors in the subacute post-stroke phase. METHODS: In this cross-sectional study ancillary to the DOBRAS cohort, individuals were assessed as soon they could complete a full posturography session (with and without vision) after a first hemispheric stroke. Body-weight distribution on the mediolateral (ML) axis, position of the center of pressure on the antero-posterior (AP) axis, and postural sway on both axes were computed. Balance ability in daily life was quantified with the Postural Assessment Scale for Stroke. Data were analyzed by principal component and hierarchical clustering analyses as well as multiple linear regression. RESULTS: We enrolled 95 individuals (median age: 67.0 years [Q1; Q3 56.0; 72.0]; 68% males). Vision suppression had a marginal effect, only increasing postural sway. Regardless of the visual condition, posturographic behavior was captured by a set of 3 indices that explained almost all the information. One postural sway index (ML or AP) gave more information (48%) than both position indices (ML 26% and AP 15%). These 3 indices identified 3 standing behaviors: 1) stable and symmetric, 2) asymmetric, unstable, and positioned backward, and 3) very unstable and positioned forward. Balance ability in daily life was explained (49% of the information, 95%CI [35; 63]) by weight-bearing asymmetry and postural sway on the ML axis, which played an independent role (both p<10-5), with similar impact. CONCLUSIONS: Three typical behaviors allow standing after stroke: described by only 3 posturographic indices. Weight-bearing asymmetry is not the primary parameter and should not be considered in isolation as an outcome. To increase the feasibility of posturography in the early subacute phase and to simplify evaluation sessions, trials could be limited to eyes open. REGISTRATION: NCT03203109.

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.

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 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 have 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 poststroke lateropulsion. We followed MOOSE and PRISMA guidelines. Eligibility for inclusion, data extraction, and study quality (Joanna Briggs Institute guidelines) were evaluated by 2 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 poststroke phases) and metaregression. RESULTS: We identified 22 studies (5,125 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% 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. Metaregression 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). DISCUSSION: Poststroke lateropulsion prevalence is high, which appeals for its systematic detection to guide early interventions. Uprightness is predominantly controlled from the right hemisphere.

Cognitive assessment scale for stroke patients (CASP): A multicentric validation study.

BACKGROUND: The Mini Mental State Examination and Montreal Cognitive Assessment are commonly used as short screening batteries for assessing cognitive impairment after stroke. However, aphasia or hemispatial neglect may interfere with the results. For this reason, we developed the Cognitive Assessment scale for Stroke Patients (CASP), which takes these conditions into consideration and previously demonstrated its superiority over these scales in terms of feasibility. OBJECTIVES: Our goal was to verify the psychometric properties of the (original) French version of the CASP. METHODS: We included 201 patients with a recent first hemispheric stroke and 50 controls. Stroke patients were examined 4 times (visit 1 [V1] to visit 4 [V4]) in the subacute post-stroke phase. The structural validity of the CASP was studied by principal factorial analysis, convergent validity by comparison with several variables including a comprehensive neuropsychological assessment, divergent validity by comparison with the total score between stroke patients and controls, and sub-scores between right and left stroke. Internal consistency, reproducibility and sensitivity to change were assessed. We propose the Minimal Clinically Important Difference (MCID) value and a pathological threshold as well as a threshold to predict cognitive change between V1 and V4. RESULTS: Of the 201 participants included (63% male; mean [SD] age 63 [13] years), CASP data were available for 199/150/133/93 at V1/V2/V3/V4, respectively. CASP has a one-dimensional structure. The hypotheses of convergent/divergent validities were confirmed. Internal consistency was good and reliability excellent. Responsiveness was small to moderate, but the MCID could still be estimated. We discuss the choice of a pathological threshold and a predictive threshold of V1 over V4. CONCLUSIONS: CASP has good psychometric properties for screening cognitive impairment in the subacute post-stroke phase, which is consistent with its Italian and Korean versions. It can be used for patients with severe motor aphasia or left hemispatial neglect but not in case of severe oral comprehension or visual impairment.

Recovery of balance and gait after stroke is deteriorated by confluent white matter hyperintensities: Cohort study.

BACKGROUND: White matter hyperintensities (WMHs) are well known to affect post-stroke disability, mainly by cognitive impairment. Their impact on post-stroke balance and gait disorders is unclear. OBJECTIVES: We aimed to test the hypothesis that WMHs would independently deteriorate post-stroke balance and gait recovery. METHODS: This study was performed in 210 individuals of the cohort Determinants of Balance Recovery After Stroke (DOBRAS), consecutively enrolled after a first-ever hemisphere stroke. Clinical data were systematically collected on day 30±3 (D30) post-stroke and at discharge from the rehabilitation ward. WMHs were searched on MRI, graded with the Fazekas scale, and dichotomized as no/mild (absence/sparse) or moderate/severe (confluent). The primary endpoint was the recovery of the single limb stance, assessed with the Postural Assessment Scale for Stroke (PASS). The secondary endpoint was the recovery of independent gait, assessed with the modified Fugl-Meyer Gait Assessment (mFMA). The adjusted hazard ratios (aHRs) of achievements of these endpoints by level of WMHs were estimated by using Cox models, accounting for other relevant clinical and imaging factors. RESULTS: Individuals with moderate/severe WMHs (n=86, 41%) had greater balance and gait disorders and were more often fallers than others (n=124, 59%). Overall, they had worse and slower recovery of single limb stance and independent gait (P<0.001). Moderate/severe WMHs was the most detrimental factor for recovery of balance (aHR 0.46, 95% confidence interval [CI] 0.32-0.68, P<0.001) and gait (0.51, 0.35-0.74, P<0.001), along with age, stroke severity, lesion volume and disrupted corticospinal tract. With cerebral infarct, endovascular treatments had an independent positive effect, both on the recovery of balance (aHR 1.65, 95% CI 1.13-2.4, P=0.009) and gait (1.78, 1.24-2.55, P=0.002). CONCLUSIONS: WMHs magnify balance and gait disorders after stroke and worsen their recovery. They should be better accounted for in post-stroke rehabilitation, especially to help establish a prognosis of mobility. CLINICALTRIALS. GOV REGISTRATION: NCT03203109.

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 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.

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.

Contribution of Basal Ganglia to the Sense of Upright: A Double-Blind Within-Person Randomized Trial of Subthalamic Stimulation in Parkinson's Disease with Pisa Syndrome.

BACKGROUND: Verticality perception is frequently altered in Parkinson's disease (PD) with Pisa syndrome (PS). Is it the cause or the consequence of the PS? OBJECTIVE: We tested the hypothesis that both scenarios coexist. METHODS: We performed a double-blind within-person randomized trial (NCT02704910) in 18 individuals (median age 63.5 years) with PD evolving for a median of 17.5 years and PS for 2.5 years and treated with bilateral stimulation of the subthalamus nuclei (STN-DBS) for 6.5 years. We analyzed whether head and trunk orientations were congruent with the visual (VV) and postural (PV) vertical, and whether switching on one or both sides of the STN-DBS could modulate trunk orientation via verticality representation. RESULTS: The tilted verticality perception could explain the PS in 6/18 (33%) patients, overall in three right-handers (17%) who showed net and congruent leftward trunk and PV tilts. Two of the 18 (11%) had an outstanding clinical picture associating leftward: predominant parkinsonian symptoms, whole-body tilt (head -11°, trunk -8°) and transmodal tilt in verticality perception (PV -10°, VV -8.9°). Trunk orientation or VV were not modulated by STN-DBS, whereas PV tilts were attenuated by unilateral or bilateral stimulations if it was applied on the opposite STN. CONCLUSION: In most cases of PS, verticality perception is altered by the body deformity. In some cases, PS seems secondary to a biased internal model of verticality, and DBS on the side of the most denervated STN attenuated PV tilts with a quasi-immediate effect. This is an interesting track for further clinical studies.

A randomized sham-controlled trial on the effect of continuous positive airway pressure treatment on gait control in severe obstructive sleep apnea patients.

To determine the effect of continuous positive airway pressure (CPAP), the gold standard treatment for obstructive sleep apnea syndrome (OSAS), on gait control in severe OSAS patients. We conducted a randomized, double-blind, parallel-group, sham-controlled monocentric study in Grenoble Alpes University Hospital, France. Gait parameters were recorded under single and dual-task conditions using a visuo-verbal cognitive task (Stroop test), before and after the 8-week intervention period. Stride-time variability, a marker of gait control, was the primary study endpoint. Changes in the determinants of gait control were the main secondary outcomes. ClinicalTrials.gov Identifier: (NCT02345694). 24 patients [median (Q1; Q3)]: age: 59.5 (46.3; 66.8) years, 87.5% male, body mass index: 28.2 (24.7; 29.8) kg. m-2, apnea-hypopnea index: 51.6 (35.0; 61.4) events/h were randomized to be treated by effective CPAP (n = 12) or by sham-CPAP (n = 12). A complete case analysis was performed, using a mixed linear regression model. CPAP elicited no significant improvement in stride-time variability compared to sham-CPAP. No difference was found regarding the determinants of gait control. This study is the first RCT to investigate the effects of CPAP on gait control. Eight weeks of CPAP treatment did not improve gait control in severe non-obese OSAS patients. These results substantiate the complex OSAS-neurocognitive function relationship.

Maintaining Trunk and Head Upright Optimizes Visual Vertical Measurement After Stroke.

BACKGROUND: Visual vertical (VV) measurement provides information about spatial cognition and is now part of postural disorders assessment. Guidelines for clinical VV measurement after stroke remain to be established, especially regarding the orientation settings for patients who do not sit upright. OBJECTIVES: We analyzed the need to control body orientation while patients estimate the VV. METHODS: VV orientation and variability were assessed in 20 controls and 36 subacute patients undergoing rehabilitation after a first hemisphere stroke, in 3 settings: body not maintained (trunk and head free), partially maintained (trunk maintained, head free), or maintained (trunk and head). VV was analyzed as a function of trunk and head tilt, also quantified. RESULTS: Trunk and head orientations were independent. The ability to sit independently was affected by a tilted trunk. The setting had a strong effect on VV orientation and variability in patients with contralesional trunk tilt (n = 11; trunk orientation -18.4 ± 11.7°). The contralesional VV bias was severe and consistent under partially maintained (-8.4 ± 5.2°) and maintained (-7.8 ± 3.5°) settings, whereas various individual behaviors reduced the mean bias under the nonmaintained setting (-3.6 ± 9.3°, P < .05). VV variability was lower under the maintained (1.5 ± 0.2°) than nonmaintained (3.7 ± 0.4°, P < .001) and partially maintained (3.6 ± 0.2°, P < .001) settings. In contrast, setting had no effect in patients with satisfactory postural control in sitting. CONCLUSION: Subject setting improves VV measurement in stroke patients with postural disorders. Maintaining the trunk upright enhances the validity of VV orientation, and maintaining the head upright enhances the validity of within-subject variability. Measuring VV without any body maintaining is valid in patients with satisfactory balance abilities.