Normal subjects with different sagittal spino-pelvic morphotypes may walk differently

Abstract

, M. Salavati, A.M. ArablooUniversity of Social Welfare and RehabilitationSciences, Tehran, Islamic Republic of IranResearch question: To clarify the relation between attentionand balance in patients with nonspecific low back pain (NSLBP), byassessing feet-in-place balance recovery reactions under differentconditions of cognitive and postural difficulty.Introduction: Patients with LBP demonstrate altered posturalresponses following perturbations [1]. Deficits in sensory/motorsystemshavebeenproposedtoberelatedtothesealterations[2,3].Aswellassensory/motorsystems,higher-cognitiveprocesseshavecontribution in the process of regaining balance and interactionbetween posture and cognition depends on factors such as diffi-culty of postural task [4,5]. However, little is known about the roleof cognitive processes in postural control of LBP.Materials and methods: 20 patients with NSLBP and 20matched controls between the ages of 18 and 45, stood on a move-ableplatformwitheachfootonaseparateforceplateandmaintaintheir balance (a) while expecting a series of forward/backwardtranslations of the support surface at two different sizes (b) with(DT)andwithout(ST-Balance)performingacognitivetask.Thecog-nitive (Auditory Stroop) task was also performed while standing(ST-cognition). Perturbation magnitude was scaled to the sub-ject’s height, while maintaining the translation duration across allsubjects. Resultant sway had 6 and 8?/s angular momentum formediumandlargesizesofperturbation,respectively.Faceplatesig-nals were used to determine anteroposterior excursion of center ofpressure (CoP) to find reaction time (time from perturbation onsetto onset of subject reaction), latency (time from onset of subjectreaction to Maximum amplitude of response), Max amplitude andinitial velocity of response (mean velocity between onset of reac-tion and max amplitude). The mean of 3 trials of CoP parametersand cognitive reaction times was used for statistical analysis.Results: In LBP group CoP responses were delayed in reactiontime and latency, also reduced in velocity compared to controls. Atsmallersizeofperturbation,theadditionalcognitiveloadincreasedvelocity in LBP group but decreased this variable at larger sizeof perturbation. Reaction time of stroop task was significantlyincreasedinDTcomparedtoST-cognitionconditionsandwasover-all slower in LBP group compared to controls.Discussion: Detrimental changes in balance control of LBP suf-ferers were influenced differently by cognitive task. This finding,in combination with overall poorer performance of cognitive taskmay imply altered cognitive regulation of balance control in LBP.Because level of postural difficulty affects adaptation of posturalstrategy under cognitive loading (may be due to different posturaltreatvalue),bothcognitiveandposturalchallengingshouldbecon-sidered in rehabilitation of these patients.References