Disturbances of spatial reference frame and postural asymmetry after a chronic stroke.

Asymmetrical postural behaviors are frequently observed after a stroke. They are due in part to the sensorimotor deficit, but they could also be related to a disorder of the representation of the body in space. The objective was to determine whether the asymmetrical postural behaviors of chronic stroke patients are related with a disruption of the perception of spatial frame. 30 chronic stroke patients (mean age 60.3 year ± 10, mean delay post-stroke 4.78 year ± 3), 15 patients with right brain damage (RBD) and 15 patients with left brain damage (LBD), and 20 healthy subjects participated in the study. Postural asymmetry was detected by the evaluation of body weight repartition on a force platform (weight body asymmetry) and was related to the longitudinal body axis (LBA) and the subjective straight ahead (SSA) (egocentric space representation) and to the subjective visual vertical (SVV) (allocentric space representation) by a multivariate analysis of variance adjusted with motor function and sensitivity as covariables. Both patients with RBD (35% ± 8) and LBD (39% ± 4) had body weight asymmetry and there was still space misperception at this stage of recovery, especially in the RBD group. WBA was related to LBA when considering both patients with RBD and LBD (p = 0.03). However, this relation was dependent on the side of the lesion (p = 0.0006) with a stronger relation in the RBD group (0.01). No relation with WBA was found neither with SSA (p = 0.58) nor with SVV (p = 0.47). This study pointed out a strong relationship between disturbance in the perception of the longitudinal body axis and postural asymmetry in chronic strokes, and especially within the RBD group. Conversely, no other spatial perturbations seemed to be involved in this particular postural behavior.

The Neural Bases of Egocentric Spatial Representation for Extracorporeal and Corporeal Tasks: An fMRI Study.

(1) Background: Humans use reference frames to elaborate the spatial representations needed for all space-oriented behaviors such as postural control, walking, or grasping. We investigated the neural bases of two egocentric tasks: the extracorporeal subjective straight-ahead task (SSA) and the corporeal subjective longitudinal body plane task (SLB) in healthy participants using functional magnetic resonance imaging (fMRI). This work was an ancillary part of a study involving stroke patients. (2) Methods: Seventeen healthy participants underwent a 3T fMRI examination. During the SSA, participants had to divide the extracorporeal space into two equal parts. During the SLB, they had to divide their body along the midsagittal plane. (3) Results: Both tasks elicited a parieto-occipital network encompassing the superior and inferior parietal lobules and lateral occipital cortex, with a right hemispheric dominance. Additionally, the SLB > SSA contrast revealed activations of the left angular and premotor cortices. These areas, involved in attention and motor imagery suggest a greater complexity of corporeal processes engaging body representation. (4) Conclusions: This was the first fMRI study to explore the SLB-related activity and its complementarity with the SSA. Our results pave the way for the exploration of spatial cognitive impairment in patients.

Intracavernous Injections in Spinal Cord Injured Men With Erectile Dysfunction, a Systematic Review and Meta-Analysis.

INTRODUCTION: Despite improvements in the care of patients after spinal cord injury (SCI), permanent impairment of locomotion, sensation, and autonomic function remains a major hurdle. After the acute stage of injury, recovering sexual function is a high priority. AIM: To review the efficacy of intracavernous injections (ICIs) in men with SCI and to identify prognostic factors affecting the efficacy of ICIs in this population. METHODS: Systematic review of the literature was conducted using the PubMed-Medline, Embase, EBSCO, Web of Science, and Cochrane Library databases. The literature search was restricted to articles published in English, French, and Spanish up to November 2014 using the key words alprostadil, papaverine, moxisylite, alpha-blocking agent, phentolamine, intracavernous injection, spinal cord injuries, paraplegia, quadriplegia, and erectile dysfunction. Studies involving patients with SCI and erectile dysfunction treated with ICIs of alprostadil, papaverine, and α-blocking agents, including retrospective and prospective cohorts, population studies, and randomized controlled trials, were included. MAIN OUTCOME MEASURE: Overall response rate to ICI for erectile dysfunction in patients with SCI. RESULTS: Of 283 studies identified, 23 involved 713 patients with SCI. ICIs resulted in successful erections in 88% of patients (n = 713, 95% CI = 83%-92%). Erections were obtained in 93% of patients (n = 101, 95% CI = 83%-99%) with the combination of papaverine and phentolamine, in 91% (n = 274, 95% CI = 78%-97%) with papaverine alone, and in 80% (n = 119, 95% CI = 64%-90%) with alprostadil. Type of injected drug, doses, level of injury (complete or incomplete), extent of injury, age, time since injury, and persistence or transience of erections were evaluated, but statistical analysis could not identify specific factors predictive of a response to ICI. CONCLUSION: ICIs are an effective treatment of erectile dysfunction in men with SCI. No predictive factor for efficacy could be identified. Studies comparing the response to ICI in upper vs lower motor neuron lesions could improve our understanding of ICI failure.