title: Balance recovery reactions in individuals with recurrent nonspecific low back pain: Effect of attention.
abstract: People who suffer from Low Back Pain (LBP) demonstrate impaired postural control. Deficits in sensory-motor systems have been proposed to be related to these changes. Considering higher cognitive process contribution to postural control, the aim of this study was to investigate the effects of cognitive load on balance control of patients with LBP. Twenty subjects with recurrent non-specific LBP and 20 healthy controls participated. They stood on a moveable platform with each foot placed on a separate force plate. They were asked to maintain their balance (a) while expecting translations of the support surface at two sizes of perturbation (b) with and without performing a cognitive (auditory Stroop) task. The outcomes included reaction time (RT), latency, initial velocity and amplitude of center of pressure response for balance, and RT for cognitive performance. Compared to the healthy group, LBP group demonstrated delayed RT and latency, and reduced initial velocity (P<0.05). Moreover, they had slower Stroop RT (F=70.88, P<0.001). Concurrent performance of tasks resulted in increased Stroop RT (F=3.42, P=0.03) and adaptation in initial velocity (F=6.70, P=0.01). At the smaller size of perturbation, cognitive load increased velocity in LBP group but decreased this variable in the healthy group. When the cognitive load was added at the larger size of perturbation, velocity of response decreased in LBP group (P<0.05). These findings imply altered cognitive regulation of dynamic balance in patients with LBP and suggest that the adopted strategy might alter depending upon the characteristics of the postural challenge.
authors.affiliation: Department of Physiotherapy, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran; Department of Rehabilitation Sciences, Mazandaran University of Medical Sciences, Sari, Iran. Electronic address: etemadi_y62@yahoo.com.
authors.forename: Yasaman
authors.initials: Y
authors.lastname: Etemadi
authors.affiliation: Department of Physiotherapy, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
authors.forename: Mahyar
authors.initials: M
authors.lastname: Salavati
authors.affiliation: Department of Physiotherapy, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
authors.forename: Amir M
authors.initials: AM
authors.lastname: Arab
authors.affiliation: Musculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; Department of Physiotherapy, Faculty of Rehabilitation, Tabriz University Of Medical Sciences, Tabriz, Iran.
authors.forename: Tabassom
authors.initials: T
authors.lastname: Ghanavati
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D016022:Case-Control Studies; D003071:Cognition / Q000502:physiology*; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D004856:Postural Balance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*
keywords: Cognition; Dual task; Dynamic balance; Low back pain; Surface perturbations