Poststroke cognitive outcome is better accounted for by white matter abnormalities automated segmentation than visual analysis.

BACKGROUND AND AIMS: The association between white matter abnormalities (WMA) and cognitive decline previously reported in poststroke patients has been mainly documented using visual scales. However, automated segmentation of WMA provides a precise determination of the volume of WMA. Nonetheless, it is rarely used in the stroke population and its potential advantage over visual scales is still unsettled. The objective of this study was to examine whether automated segmentation of WMA provides a better account than the visual Fazekas and Wahlund scales of the decline in executive functions and processing speed in stroke patients. METHODS: The analyses were conducted on the 358 patients of the GRECogVASC cohort with an MRI performed at six months poststroke in the Amiens center. WMA were visually analyzed using the Fazekas (subcortical abnormalities) and Wahlund scales. Segmentation was performed using LST (3.0.3). Following preliminary studies to determine the optimal segmentation threshold, we examined the relationship between cognitive status and WMA volume computed at each threshold using receiver operating characteristic (ROC) curves. Finally, we assessed the ability of both Fazekas and Wahlund visual scores and WMA volume to account for cognitive scores by using a bivariate Pearson correlation analysis, comparing correlation coefficients with the Fisher transformation and repeating correlation analysis after adjustment for the lesion volume. RESULTS: Increasing the threshold led to an underestimation of WMA (P=0.0001) (significant for a threshold ≥0.2) and an improvement in correct rejection of signal changes in the stroke cavity (P=0.02) (significant for a threshold ≤0.5), susceptibility artifacts (P=0.002) (significant for a threshold ≤0.6), and corticospinal degeneration (P=0.03) (significant for a threshold ≤0.5). WMA volume decreased with increasing threshold (P=0.0001). Areas under the curve (AUC) did not differ according to the threshold (processing speed: P=0.85, executive cognitive functions: P=0.7). Correlation coefficients between cognitive scores and WMA were higher for WMA volume than the Fazekas (processing speed: Z=-3.442, P=0.001; executive functions: Z=-2.751, P=0.006) and Wahlund scores (processing speed: Z=-3.615, P=0.0001; executive functions: Z=-2.769, P=0.006). Adjustment for lesion volume did not alter the correlations with WMA volume (processing speed: r=-0.327 [95%CI: -0.416; -0.223], P=0.0001; executive functions: r=-0.262 [95%CI: -0.363; -0.150], P=0.0001). CONCLUSION: This study shows that WMA volume assessed by automated segmentation provides a better account of cognitive disorders than visual analysis. This should favor its wider use to refine imaging determinants of poststroke cognitive disorders.

Difference between individuals with left and right hemiparesis in the effect of gluteus medius vibration on body weight shifting.

OBJECTIVE: To test the effect of gluteus medius (GM) vibration on the reduction of asymmetric body weight distribution in individuals with hemiparesis (HP) at two stages of postural recovery. METHODS: The effects of GM vibration according to the shift of the body weight (%Shift) onto the paretic leg during GM vibration were registered while standing on a force-platform in 40 HP (19 left and 21 right; mean age 54.7±10.6years, mean time after stroke 2.0±1.3months), as soon as they could stand without assistance and 4 to 6 weeks later, and in 40 control subjects (mean age 54.7±10.5years). RESULTS: Without vibration, baseline body weight (BW) distribution was characterized by underloading of the paretic limb (mean BW on the paretic limb 37.2%±13.1%). At the early stage of balance recovery, % shift toward the paretic limb induced by GM vibration differed significantly between left and right HP (P=0.049) and between left HP and controls (C) (P=0.022) and was related to BW asymmetry (r=0.437, P=0.004). Later, GM vibration reduced asymmetric BW distribution in most HP and no difference was found between left and right HP and between left and C. CONCLUSION: At an advanced stage of postural recovery, GM vibration could help encourage HP to put weight on the affected limb. Interestingly, a behavioral difference was initially observed between right and left HP that could probably be explained by a different strategy due to the baseline severity of the BW asymmetry.

Motor strategies of postural control after hemispheric stroke.

After stroke, the causes of balance disorders include motor disorders, sensory loss, perceptual deficits and altered spatial cognition. This review focuses on motor strategies for postural control after stroke. Weight-bearing asymmetry, smaller surface of stability, increased sway, body tilting and sometimes pushing syndrome are observed. Weakness and sensory impairments account only for some of these disturbances; altered postural reactions and anticipated postural adjustments as well as abnormal synergistic muscular activation play an important part. These disorders are often linked to cognitive impairments (visuospatial analysis, perception of verticality, use of sensory information, attention, etc.), which explain the preeminent disorders of postural control seen with right rather than left-hemisphere lesions. Most of the motor changes are due to an impaired central nervous system but some could be considered adaptive behaviors. These changes have consequences for rehabilitation and need further studies for building customized programs based on the motor comportment of a given patient.

Walking with eyes closed is easier than walking with eyes open without visual cues: The Romberg task versus the goggle task.

BACKGROUND: The Romberg test, with the subject standing and with eyes closed, gives diagnostic arguments for a proprioceptive disorder. Closing the eyes is also used in balance rehabilitation as a main way to stimulate neural plasticity with proprioceptive, vestibular and even cerebellar disorders. Nevertheless, standing and walking with eyes closed or with eyes open in the dark are certainly 2 different tasks. We aimed to compare walking with eyes open, closed and wearing black or white goggles in healthy subjects. METHODS: A total of 50 healthy participants were randomly divided into 2 protocols and asked to walk on a 5-m pressure-sensitive mat, under 3 conditions: (1) eyes open (EO), eyes closed (EC) and eyes open with black goggles (BG) and (2) EO, EO with BG and with white goggles (WG). Gait was described by velocity (m·s(-1)), double support (% gait cycle), gait variability index (GVI/100) and exit from the mat (%). Analysis involved repeated measures Anova, Holm-Sidak's multiple comparisons test for parametric parameters (GVI) and Dunn's multiple comparisons test for non-parametric parameters. RESULTS: As compared with walking with EC, walking with BG produced lower median velocity, by 6% (EO 1.26; BG 1.01 vs EC 1.07 m·s(-1), P=0.0328), and lower mean GVI, by 8% (EO 91.8; BG 66.8 vs EC 72.24, P=0.009). Parameters did not differ between walking under the BG and WG conditions. CONCLUSION: The goggle task increases the difficulty in walking with visual deprivation compared to the Romberg task, so the goggle task can be proposed to gradually increase the difficulty in walking with visual deprivation (from eyes closed to eyes open in black goggles).

Intrathecal baclofen in cerebral palsy. A retrospective study of 25 wheelchair-assisted adults.

OBJECTIVE: To study the efficacy and safety of intrathecal baclofen therapy (ITB) in wheelchair-dependent adults with cerebral palsy. PATIENTS AND METHODS: A retrospective analysis and clinical examination of 25 wheelchair-assisted adults with cerebral palsy receiving ITB initiated between 1999 and 2009 in three different cities in western France. RESULTS: ITB improves spasticity and facilitates wheelchair comfort and nursing care. The therapy has an effect on motor disorders and pain. Eighty percent of the ITB patients were satisfied. Dissatisfaction was related to complications or adverse events and not lack of efficacy. Complications occurred in 32% of the patients and transient interruption of the treatment or surgical removal of the ITB pump was necessary in 16% of cases. DISCUSSION AND CONCLUSION: Wider use of ITB in this indication is likely and should lead to a better understanding of the drug's pharmacological effects on motor disorders and pain. Use of the Goal Attainment Assessment Scale or Caregiver Questionnaire can help us.