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

Abstract

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.

Left-Right Side-Specific Neuropeptide Mechanism Mediates Contralateral Responses to a Unilateral Brain Injury

“…Traumatic brain injury (TBI) and stroke in patients cause postural and sensorimotor deficits that are generally contralesional and include asymmetric posture and asymmetric exacerbated withdrawal reflexes ( Dewald et al, 1999 ; Spaich et al, 2006 , 2014 ; Serrao et al, 2012 ; Wilson et al, 2017 ; Jamal et al, 2018 ). Consistently, a unilateral injury to the hindlimb sensorimotor cortex in experimental animals induces the hindlimb postural asymmetry (HL-PA) with contralesional limb flexion and asymmetry of the nociceptive withdrawal reflexes (NWRs) with greater activity on the contralesional versus ipsilesional side ( Zhang et al, 2020 ).…”

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

“…These inputs can be integrated into different and changing systems of coordinates, depending on the person's position in space and the nature of the task. The egocentric reference frame encodes spatial information centered on body coordinates [3][4][5][6][7][8]. This frame involves two spatial components, depending on the intended action: extracorporeal and corporeal [9].…”

“…In the SLB, participants are asked to divide their corporeal space into two parts. They indicate with a button press when the bar virtually divided their corporeal space into two equal parts along their body's midsagittal plane [5,[11][12][13][14]. There are well-known clinical differences between extracorporeal and corporeal tasks [5,12], and the integration of relevant information can be differentially affected following brain damage [15].…”

“…They indicate with a button press when the bar virtually divided their corporeal space into two equal parts along their body's midsagittal plane [5,[11][12][13][14]. There are well-known clinical differences between extracorporeal and corporeal tasks [5,12], and the integration of relevant information can be differentially affected following brain damage [15]. For example, differences between extracorporeal and corporeal abilities have been identified when assessing unilateral spatial neglect.…”

Influence of back support shape in wheelchairs offering pelvic support on asymmetrical sitting posture and pressure points during reaching tasks in stroke patients

“…Stroke patients have complex imbalance characteristics [8][9][10][11] and asymmetrical postures are frequently observed among these individuals [12] during gait [13], standing [14], or when seated [15,16]. Asymmetric posture relates to an increase in spasticity [17] or weight unilaterally [11,18], so occurrence of this phenomenon in subacute stroke patients could hamper their progress toward recovery.…”