Effect of Dual-Tasking on Postural Control in Subjects With Nonspecific Low Back Pain Control of sway using vibrotactile feedback of body tilt in patients with moderate and severe postural control deficits. Altered postural control in anticipation of postural instability in persons with recurrent low back pain. Postural sway in low back pain: Effects of dual tasks. Lumbar Paraspinal Muscle Function, Perception of Lumbar Position, and Postural Control in Disc Herniation-Related Back Pain Postural Control in Older Patients with Benign Paroxysmal Positional Vertigo Effects of low back pain stabilization or movement system impairment treatments on voluntary postural adjustments: a randomized controlled trial. The relative timing of trunk muscle activation is retained in response to unanticipated postural-perturbations during acute low back pain Effect of cognitive challenge on the postural control of patients with ACL reconstruction under visual and surface perturbations. Clinimetrics of postural instability in Parkinson’s disease A randomized controlled trial to determine the effect of spinal stabilization exercise intervention based on pain level and standing balance differences in patients with low back pain Effectiveness of a lumbopelvic monitor and feedback device to change postural behaviour: a protocol for the ELF cluster randomised controlled trial Repositioning accuracy and movement parameters in low back pain subjects and healthy control subjects Clinical and functional aspects of body balance in elderly subjects with benign paroxysmal positional vertigo. Preliminary investigation of the lateral postural stability of spinal cord-injured individuals subjected to dynamic perturbations Centrally initiated postural adjustments in parkinsonian patients on and off levodopa. Neuromuscular strategies for lumbopelvic control during frontal and sagittal plane movement challenges differ between people with and without low back pain.
Study Design . Three factors mixed- design with 1 between-subject and 2 within-subject factors . Objective . To compare the main effects and interactions of postural and cognitive difficulty on quiet stance between subjects with and without nonspecific low back pain ( LBP ) . Summary of Background Data . The interference between postural control and cognitive tasks depends on factors such as sensorimotor/cognitive integrity . Changes in peripheral sensory and muscular systems as well as cognitive processes have been observed in LBP patients . It was hypothesized that the effect of cognitive task on postural performance might be different in subjects with nonspecific LBP as compared with healthy individuals . To the authors ’ knowledge this has not been investigated before . Methods . Postural stability was measured by center of pressure parameters while nonspecific LBP ( n = 22 ) and healthy ( n = 22 ) subjects r and omly performed quiet st and ing task with 3 levels of difficulty ( rigid-surface eyes open , rigid-surface eyes-closed , and foam-surface eyes-closed ) in isolation or concurrently with an easy or difficult digits backward cognitive task . Results . Subjects with nonspecific LBP had less postural sway than healthy subjects , while postural sway decreased with increase in the level of cognitive difficulty . Nonspecific LBP and healthy subjects had larger postural sway at more difficult sensory conditions such as rigid-surface eyes-closed and foam-surface eyes-closed . The response to dual-tasking was not significantly different between the 2 groups . Conclusion . The dual-tasking did not change the postural performance of nonspecific LBP subjects with low level of pain and disability differently compared to healthy subjects We evaluated the effect of the vibrotactile display of body tilt upon the postural stability of vestibulopathic subjects during st and ing . Two groups were studied : those with moderate and with severe deficits as defined by postural stability test scores . They were studied under conditions of distorted sensory input , and during anterior-posterior perturbations .  Seventeen subjects , with uni- or bilateral vestibular deficits , as determined by electronystagmography and vertical axis rotation , were tested using  Equitest computerized dynamic posturography ( CDP ) . Based on their performance on the CDP they were divided into two groups having either moderate ( nine subjects ) or severe ( eight subjects ) postural control deficits . Their anterior-posterior ( A/P ) body motion at the waist was measured with a micromechanical rate gyroscope and a linear accelerometer . The result ing tilt estimate was displayed by a vibrotactile array attached to the torso . The vibration served as a tilt feedback to the subject . The subject 's performance was evaluated using the root-mean-square ( RMS ) of both the A/P body motion and center-of-pressure ( CoP ) estimates . Sensory distortions were introduced using the Equitest Sensory Organization Tests ( SOT ) . These tests are design ed to distort A/P sensory inputs while st and ing . The SOT 5 distorts proprioceptive information about ankle joint movement , while the subject st and s eyes-closed on a moving support platform that measures foot pressure . The SOT 6 adds distorted visual information about body movement instead of testing with eyes closed . Perturbations were introduced using the Equitest Motor Control Tests ( MCT ) . These move the support platform forward or backward with small , medium and large displacements in the horizontal plane while measuring subjects ' foot pressure responses . We used the medium and large backward tests . Vibrotactile display of body tilt reduced the subjects ' A/P sway and improved their balance . The finding was more evident for those subjects with severe deficits than those moderate ones . This trend was found for both SOT 5 and 6 , as well as the medium and large MCT . Additionally , during the MCT , the peak deflection and mean recovery time also decreased significantly Insight into the mechanisms of altered postural control in persons with low back pain ( LBP ) could lead to better interventions for patients with LBP . This study investigated ( 1 ) whether persons with recurrent LBP have an altered body inclination , and ( 2 ) whether anticipation of postural instability further alters body inclination . Thirty-three young healthy individuals and 56 young persons with recurrent LBP participated in this study .  The upright st and ing posture was evaluated by means of two piezo-resistive electrogoniometers and a force platform for the conditions as follows : ( 1 ) quiet stance with and without vision , and ( 2 ) in anticipation of postural instability due to a ballistic arm movement or ankle muscle vibration . No differences in body inclination were observed when visual information was available between the two groups ( P>0.05 ) . However , significant more forward inclination was seen in the persons with recurrent LBP when vision was occluded ( + 7.4 % ) and in anticipation of postural instability ( + 19 % ) ( P<0.05 ) compared to the healthy individuals . The results suggest that young persons with recurrent LBP have an altered body inclination that might be caused by anticipation of postural instability . The adopted forward inclined posture may potentially be a factor in the recurrence of LBP Recurrence quantification analysis ( RQA ) , a nonlinear method of postural analysis , was used to explore the effects of dual-tasking on postural performance in people with nonspecific low back pain ( LBP ) compared with healthy participants .  Postural performance was quantified by RQA % recurrence , % determinism , entropy and trend .  People with nonspecific LBP ( n=22 ) and unimpaired individuals ( n=22 ) r and omly performed quiet st and ing tasks with three levels of difficulty ( rigid-surface eyes open , rigid-surface eyes closed and foam-surface eyes closed ) . These tasks were performed in isolation or concurrently with an easy or difficult cognitive task . Increasing postural difficulty was associated with higher % determinism , higher entropy and lower trend in anteroposterior ( AP ) and mediolateral ( ML ) directions in people with LBP and healthy participants .  All RQA variables in the ML direction decreased as cognitive conditions became more difficult . Significant interactions between group and cognitive difficulty were shown for % recurrence , % determinism and trend in the AP direction . While healthy participants decreased % recurrence and trend by increasing the level of cognitive difficulty , the LBP patients did not . This preliminary study suggests that LBP may be one factor that modulates the posture-cognition interaction Study Design . A follow-up study evaluating postural control , lumbar movement perception , and paraspinal muscle reflexes in disc herniation-related chronic low back pain ( LBP ) before and after discectomy .  Objectives . To assess the effect of discectomy on postural control , lumbar perception , and reflex activation of paraspinal muscles during sudden upper limb loading . Summary of Background Data . Impaired muscle function , postural control , and lumbar proprioception have been observed in LBP . However , they have not been studied in sciatica patients after surgery . Methods . The study included 20 patients selected for an operation for chronic LBP caused by disc herniation and 15 controls without chronic LBP . The paraspinal muscle responses for upper limb loading during unexpected and expected conditions were measured by surface electromyography . The ability to sense lumbar rotation was assessed in a previously vali date d motorized trunk rotation unit in the seated position . The postural control was measured with a vertical force platform . Pain , disability , and depression scores were recorded . Results . Patients had poorer lumbar perception ( P = 0.012 ) and postural control ( P < 0.05 ) than did healthy controls . The postural control remained unchanged , but lumbar perception ( P = 0.054 ) and the lumbar feed-forward control ( P = 0.043 ) improved after the surgery . Conclusions . The results demonstrate impaired lumbar proprioception and postural control in sciatica patients . During short-term follow-up after operative treatment , postural control does not seem to change , but impaired lumbar proprioception and feed-forward control of paraspinal muscles seem to recover Objective . To evaluate the effectiveness of a canalith-repositioning procedure in postural control of older patients with idiopathic benign paroxysmal positional vertigo ( BPPV ) . Study Design . Prospect i ve clinical trial . Setting . A tertiary referral center . Methods . A 9-month follow-up survey with a prospect i ve design was conducted among 33 older patients with BPPV . Patients underwent static posturography ( Balance Rehabilitation Unit [ BRU ] ) and were administered the  Dizziness H and icap Inventory ( DHI ) before and after the maneuver . After the treatment , they were compared with 33 healthy older subjects . The posturography parameters were the limit of stability ( LOS ) , the center of body-pressure area ( COP ) , and the velocity of oscillation ( VOS ) under conditions of visual , somatosensory , and visual-vestibular conflict . Results . One canalith-repositioning procedure relieved most patients ’ complaints ( 54.5 % ) , and 100 % were relieved with 1 to 3 maneuvers . Total DHI score and all subscales improved after treatment ( P < .01 ) . The LOS values pretreatment ( mean [ SD ] 134.27 [ 55.32 ] cm2 ) and posttreatment ( 181.03 [ 47.79 ] cm2 ) were significantly different ( P < .01 ) . Comparative analysis of COP values showed a relevant statistical difference in 8 of 10 postmaneuver conditions ( P < .01 ) . The postmaneuver VOS showed a significant difference under 7 conflict conditions . There were no differences between the healthy older subjects and treated patients for all VOS values under all conditions and for COP values under 9 conditions . Conclusion . The canalith-repositioning procedure promotes remission of symptoms , an increase in LOS , and improvement in postural control under conditions of somatosensory and visual conflict and visual-vestibular interaction BACKGROUND People with low back pain ( LBP ) exhibit impaired anticipatory postural adjustments ( APAs ) . OBJECTIVE To evaluate whether current motor retraining treatments address LBP-associated changes in movement coordination during tasks that do and do not require APAs . DESIGN Prospect ively registered r and omized controlled trial with a blinded assessor . SETTING Outcome evaluations occurred in a university laboratory ; treatments were carried out in outpatient physical therapy clinics . PATIENTS Fifteen subjects without LBP and 33 subjects with chronic , recurrent , and nonspecific LBP . INTERVENTION Twelve subjects with LBP received  stabilization treatment , 21 received movement system impairment-based treatment , for more than 6 weekly 1-hour sessions plus home exercises . MEASUREMENTS Pre- and post-treatment , surface electromyography ( EMG ) was recorded bilaterally from trunk and leg muscles during unsupported and supported leg-lifting tasks , which did and did not require an APA , respectively . Vertical reaction forces under the contralateral leg were recorded to characterize the APA . Oswestry disability scores and numeric pain ratings were also recorded . RESULTS Persons with LBP demonstrated an impaired APA compared with persons without LBP , characterized by increased premovement contralateral force application and increased postmovement trunk EMG amplitude , regardless of the task . After treatments , both groups similarly improved in disability and function ; however , APA characteristics did not change ( ie , force application or EMG amplitude ) in either task . LIMITATIONS Treating clinicians were not blinded to treatment allocation , only short-term outcomes were assessed , and main effects of treatment do not rule out nonspecific effects of time or repeated exposure . CONCLUSIONS Movement impairments in persons with LBP are not limited to tasks requiring an APA . Stabilization and movement system impairment-based treatments for LBP do not ameliorate and may exacerbate APA impairments ( ie , excessive force application and increased post-movement trunk muscle activation ) The purpose of this study was to assess the activation of the erector spinae ( ES ) and external oblique ( EO ) in response to unanticipated , bi-directional postural perturbations before and after the induction of acute low back pain ( LBP ) in healthy individuals . An experimental session consisted of a baseline , control , and an acute LBP condition . For the control and acute LBP condition , isotonic or hypertonic saline ( HS ) , respectively , was injected into the right ES muscle . In each condition , participants stood on a moveable platform during which 32 r and omized postural perturbations ( 8 repetitions of 4 perturbation types : 8 cm anterior slides , 8 cm posterior slides , 10 ° anterior tilts , and 10 ° posterior tilts ) with varying inter-perturbation time intervals were performed over a period of 4–5 min . Bilateral surface electromyography ( EMG ) was recorded from the ES and EO in addition to subjective pain records . During the acute LBP condition : ( 1 ) the onset time of the ES and EO was delayed for the forward and backward sliding perturbations ( P < 0.05 ) ; ( 2 ) EMG amplitude was reduced bilaterally for all perturbations ( P < 0.05 ) ; ( 3 ) the order of activation and interval between the onset times of the ES and EO were unaltered and ( 4 ) ES , but not EO , activity was adjusted to account for the directional differences between the perturbations . This study revealed that re-establishment of posture and balance was a result of the individuals ’ ability to rapidly modulate ES with respect to EO activity and that the bi-directional postural responses , although shifted in time and amplitude , retained temporal features in the presence of acute LBP Our study aim ed to evaluate the effect of cognitive challenge on double-leg postural control under visual and surface perturbations of patients with anterior cruciate ligament reconstruction ( ACLR ) cleared to return to sport .  Double-leg stance postural control of 19 rehabilitated patients with ACLR ( age : 24.8 ± 6.7 years , time since surgery : 9.2 ± 1.6 months ) and 21 controls ( age : 24.9 ± 3.7 years ) was evaluated in eight r and omized situations combining two cognitive ( with and without silent backward counting in steps of seven ) , two visual ( eyes open , eyes closed ) and two surface ( stable support , foam support ) conditions . Sway area and sway path of the centre of foot pressure were measured during three 20-s recordings for each situation . Higher values indicated poorer postural control . Generally , postural control of patients with ACLR and controls was similar for sway area and sway path ( p > 0.05 ) . The lack of visual anchorage and the disturbance of the plantar input by the foam support increased sway area and sway path ( p < 0.001 ) similarly in both groups . The addition of the cognitive task  decreased sway area and sway path ( p < 0.001 ) similarly in both groups . Patients with ACLR who recently completed their rehabilitation have normalized postural control during double-leg stance tests . The use of a dual task paradigm under increased task complexity modified postural control , but in a similar way in patients with ACLR than in healthy controls . Double-leg stance tests , even under challenging conditions , are not sensitive enough to reveal postural control differences between rehabilitated patients with ACLR and controls Abstract Judgement of the ability to recover balance after a sudden shoulder pull is used as a clinical measure of postural instability in Parkinson ’s disease . To further evaluate its merits , we compared this ‘ retropulsion test ’ with dynamic posturography in 23 Parkinson patients .  Dynamic posturography involved 20 serial ‘ toe-up ’ support surface rotations , which induced backward body sway . We found a moderate correlation ( Spearman ’s ρ = 0.54 ; P < 0.05 ) between the retropulsion test and body sway after platform rotations during the ‘ off ’ phase , but no correlation during the ‘ on ’ phase ( Spearman ’s ρ = 0.43 ; P = 0.11 ) . These results cast doubt on the use of the retropulsion test as a measure of postural instability in Parkinson ’s disease Summary Background A number of studies have evaluated exercise interventions compared with other treatment strategies for subjects with recurrent low back pain ( LBP ) ; however , subject pain level and balance were not carefully considered . The purpose of this study was to investigate the effectiveness of spinal stabilization exercises ( SSE ) for managing pain and increasing balance strategy changes following unexpected perturbations in patients diagnosed with recurrent LBP . Material / Methods Twenty-one age- and gender-matched patients participated in a supervised SSE or control exercise program 5 times a week over a 4-week period . The Million Visual Analogue Scale ( MVAS ) and Oswestry Disability Index ( ODI ) were used to measure each patient ’s level of pain and disability . Balance measurements were derived from recordings of the anterior-posterior ( A/P ) and medio-lateral ( M/L ) center of pressure ( COP ) displacements during 3 consecutive , unexpected r and om perturbations . Results The level of reported pain and disability significantly decreased following treatment for both groups . Although the M/L sway was not significantly different in either group ( p=0.86 ) , there was a significant difference between group and measurement time during A/P sway ( p=0.04 ) . The A/P displacement of the SSE group significantly decreased compared with the control group . The decreased A/P displacement can be linked to the SSE intervention , which helps prevent further injury by limiting an individual ’s response rate to external perturbations . Conclusions Clinicians might consider SSE for LBP patients as a possible rehabilitation strategy to reduce A/P displacement Introduction Low back pain ( LBP ) is the most common , costly and disabling musculoskeletal disorder worldwide , and is prevalent in healthcare workers . Posture is a modifiable risk factor for LBP shown to reduce the prevalence of LBP . Our feasibility research suggests that postural feedback might help healthcare workers avoid hazardous postures . The Effectiveness of Lumbopelvic Feedback ( ELF ) trial will investigate the extent to which postural monitor and feedback ( PMF ) can reduce exposure to hazardous posture associated with LBP . Methods This is a participant-blinded , r and omised controlled trial with blocked cluster r and om allocation . Participants will include volunteer healthcare workers recruited from aged care institutions and hospitals . A postural monitoring and feedback device will monitor and record lumbopelvic forward bending posture , and provide audio feedback whenever the user sustains a lumbopelvic forward bending posture that exceeds predefined thresholds . The primary outcome measure will be postural behaviour ( exceeding thresholds ) . Secondary outcome measures will be incidence of LBP , participant-reported disability and adherence . Following baseline assessment , we will r and omly assign participants to 1 of 2 intervention arms : a feedback group and a no-feedback control group . We will compare between-group differences of changes in postural behaviour by using a repeated measures mixed-effect model analysis of covariance ( ANCOVA ) at 6 weeks . Postural behaviour baseline scores , work-related psychosocial factors and disability scores will be input as covariates into the statistical models . We will use logistic mixed model analysis and Cox 's proportional hazards for assessing the effect of a PMF on LBP incidence between groups . Discussion Posture is a modifiable risk factor for low back disorders . Findings from the ELF trial will inform the design of future clinical trials assessing the effectiveness of wearable technology on minimising hazardous posture during daily living activities in patients with low back disorders . Trial registration number ACTRN12616000449437 Study Design : A control group study with repeated measures . Objective : To compare  trunk repositioning parameters  in chronic low back pain ( LBP ) and healthy subjects . Summary and background data : Recent evidence suggests that chronic LBP patients exhibit deficits in trunk proprioception and motor control . Trunk repositioning and the various spatio-temporal parameters related to it can be used to evaluate sensori-motor control and movement strategies . Methods : Fifteen control subjects and 16 chronic LBP subjects participated in this study . Subjects were required to reproduce different trunk position in flexion ( 15 ° , 30 ° and 60 ° ) and extension ( 15 ° ) . In the learning phase preceding each condition , visual feedback was provided . Following these learning trials , subjects were asked to perform ten consecutive trials without any feedback . Movement time , movement time variability and peak velocity were obtained and a temporal symmetry ratio was calculated . Peak angular position variability and absolute error in peak angular position were also calculated to evaluate spatial accuracy . Results : Two subgroups of LBP patients were identified . One subgroup of LBP subjects demonstrated longer movement time and smaller peak velocities and symmetry ratios than normal subjects . No group difference was observed for peak angular position variability and absolute error in peak angular position . Conclusion : Chronic LBP patients , when given a sufficient learning period , were able to reproduce trunk position with a spatial accuracy similar to control subjects . Some LBP subjects , however , showed modifications of movement time , peak velocity and acceleration parameters . We propose that the presence of persistent chronic pain could induce an alteration or an adaptation in the motor responses of chronic LBP subjects UNLABELLED Benign paroxysmal positional vertigo ( BPPV ) may compromise the balance of elderly subjects . OBJECTIVE To observe the effects of the Epley maneuver in elderly subjects with BPPV and assess clinical and functional aspects of body balance . METHOD This is a prospect i ve clinical study . Patients diagnosed with BPPV ( Dix-Hallpike test ) were su bmi tted to the Timed Up & Go ( TUG ) test , the Clinical Test of Sensory Interaction and Balance ( CTSIB ) , and lower limb testing before and after they were repositioned using the modified Epley maneuver . RESULTS Most subjects were females , and the group 's mean age was 70.10 years ( SD = 7.00 ) . All patients had canalithiasis of the posterior canal . The following symptoms improved after the maneuver : postural instability ( p = 0.006 ) , nausea and vomiting ( p = 0.021 ) , and tinnitus ( p = 0.003 ) . Subjects improved their times significantly in the TUG and lower limb tests after the Epley maneuver ( p < 0.001 ) . Patients performed better on the CTSIB after the Epley maneuver  on condition 2 ( p < 0.003 ) , condition 3 ( p < 0.001 ) , condition 4 ( p < 0.001 ) , condition 5 ( p < 0.001 ) , and condition 6 ( p < 0.001 ) . CONCLUSION Clinical and functional aspects of body balance in elderly with BPPV improved after treatment with the modified Epley maneuver Study Design : A study of the impact of spinal cord injury ( SCI ) on seated balance was conducted by comparing the results obtained from experiments with able-bodied and SCI subjects . Objectives : The purpose of this preliminary study was to examine the lateral postural stability of seated individuals with SCI in a dynamic environment . Setting : Experiments were conducted at the Clevel and Clinic Foundation in Clevel and , Ohio . Methods : Controlled perturbations were applied to each subject , seated in a wheelchair , through the use of a servo-controlled tilt platform . The platform was rotated so as to create disturbances similar in nature to those experienced in the frontal plane during left turns in a vehicle . Four quadriplegic , four paraplegic , and five able-bodied subjects participated in this study . Kinematic information and center of pressure ( COP ) movement were recorded . Results : None of the spinal cord-injured subjects was able to maintain his stability when exposed to the stronger perturbations , while all of the able-bodied subjects stayed upright for all of the trials . On an individual basis , injury level was not always indicative of balance . However , regression results suggest a correlation between ability to perform static leaning and dynamic balance ( P<0.001 ) . Conclusions : SCI subjects lost stability under dynamic conditions even though they were stable in the static situation . Initial results also raise some questions about where and when external support may be needed . Information of this nature could help to guide the design of new lateral supports with improved client acceptance This study investigates the effects of  parkinsonism  and  dopamine replacement therapy ( levodopa ) on central ly initiated postural activity preceding rising onto the toes . The electromyographic ( EMG ) and force magnitude , scaling , sequencing , and postural stabilization were compared when rising-to-toes under two conditions , slow/low versus fast/high , for parkinsonian patients and elderly control subjects . Parkinsonian subjects were tested after withholding their levodopa medication for 12 - 16 h and again 1 h after taking their medication when parkinsonian signs were diminished . Parkinsonian subjects showed reduced magnitudes and delayed timing of the postural and voluntary components of the rise-to-toes task , as if they had difficulty turning off the postural , tibialis anterior ( TIB ) component and initiating the voluntary , gastrocnemius ( GAS ) component . Dopamine improved the relative timing , as well as the magnitude of both postural and voluntary components of rise-to-toes . Although the magnitude of dorsiflexion torque was smaller for parkinsonian subjects ON and OFF than for healthy elderly controls , the parkinsonian subjects showed intact scaling of the magnitude of postural activity . Parkinsonian subjects do not perform the rise-to-toes task like normal subjects who are instructed to rise slowly ; the relative timing of TIB and GAS activation was different even at comparable speeds of performance . Parkinsonian subjects , both ON and OFF , exhibited greater risk of falling than elderly control subjects when rising to toes . This increased risk of falling was reflected in a smaller safety margin between the peak center of mass ( CoM ) and peak center of pressure ( CoP ) during the task . The magnitude of mean postural dorsiflexion torque in the rise-to-toes task was highly correlated with a clinical rating scale of gait and balance , suggesting that force control is a critical factor influencing postural control in patients with Parkinson 's disease Observation-based assessment s of movement are a st and ard component in clinical assessment of patients with non-specific low back pain . While aberrant motion patterns can be detected visually , clinicians are unable to assess underlying neuromuscular strategies during these tests . The purpose of this study was to compare coordination of the trunk and hip muscles during 2 commonly used assessment s for lumbopelvic control in people with low back pain ( LBP ) and matched control subjects .  Electromyography was recorded from hip and trunk muscles of 34 participants ( 17 with LBP ) during performance of the Active Hip Abduction ( AHAbd ) and Active Straight Leg Raise ( ASLR ) tests .  Relative muscle timing was calculated using cross-correlation . Participants with LBP demonstrated a variable strategy , while control subjects used a consistent proximal to distal activation strategy during both frontal and sagittal plane movements . Findings from this study provide insight into underlying neuromuscular control during commonly used assessment tests for patients with LBP that may help to guide targeted intervention approaches
A previous review concluded that postural sway is increased in patients with low back pain ( LBP ) .
In a minority of studies , a decreased sway was found in LBP patients .
There were no systematic differences between studies finding an effect and those reporting no effect of LBP .
The proportion of studies finding between-group differences did not increase with increased complexity of sensory manipulations .
However , more detailed analysis of the literature shows that postural deficit may be dependent on experimental conditions in which patients with LBP have been assessed .
The research question to be answered in this review was : " Is there any difference in postural sway between subjects with and without LBP across several sensory manipulation conditions ? " .