Association of cognitive domains with postural instability/gait disturbance in Parkinson's disease.

INTRODUCTION: Research suggests an association between global cognition and postural instability/gait disturbance (PIGD) in Parkinson disease (PD), but the relationship between specific cognitive domains and PIGD symptoms is not clear. This study examined the association of cognition (global and specific cognitive domains) with PIGD symptoms in a large, well-characterized sample of individuals with PD. METHODS: Cognitive function was measured with a detailed neuropsychological assessment, including global cognition, executive function, memory, visuospatial function, and language. PIGD symptoms were measured using the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III, Motor Examination subscale. Multiple linear regression analyses were performed to assess the relationship between cognition and PIGD symptoms with models adjusting for age, sex, education, enrollment site, disease duration, and motor symptom severity. RESULTS: The analysis included 783 participants, with mean (standard deviation) age of 67.3 (9.7) years and median (interquartile range) MDS-UPDRS Motor Subscale score of 26 (17, 35). Deficits in global cognition, executive function, memory, and phonemic fluency were associated with more severe PIGD symptoms. Deficits in executive function were associated with impairments in gait, freezing, and postural stability, while visuospatial impairments were associated only with more severe freezing, and poorer memory function was associated only with greater postural instability. DISCUSSION: While impairments in global cognition and aspects of executive functioning were associated with more severe PIGD symptoms, specific cognitive domains were differentially related to distinct PIGD components, suggesting the presence of multiple neural pathways contributing to associations between cognition and PIGD symptoms in persons with PD.

The influence of a concurrent cognitive task on the compensatory stepping response to a perturbation in balance-impaired and healthy elders.

This study investigated the influence of a concurrent cognitive task on the compensatory stepping response in balance-impaired elders and the attentional demand of the stepping response. Kinetic, kinematic and neuromuscular measures of a forward recovery step were investigated in 15 young adults, 15 healthy elders and 13 balance-impaired elders in a single task (postural recovery only) and dual task (postural recovery and vocal reaction time task) situation. Results revealed that reaction times were longer in all subjects when performed concurrently with a compensatory step, they were longer for a step than an in-place response and longer for balance-impaired older adults compared with young adults. An interesting finding was that the latter group difference may be related to prioritization between the two tasks rather than attentional demand, as the older adults completed the step before the reaction time, whereas the young adults could perform both concurrently. Few differences in step characteristics were found between tasks, with the most notable being a delayed latency and reduced magnitude of the early automatic postural response in healthy and balance-impaired elders with a concurrent task.

The interacting effects of cognitive demand and recovery of postural stability in balance-impaired elderly persons.

BACKGROUND: Although postural recovery is attentionally demanding in healthy elderly persons, an inability to recover balance due to competition for attentional resources between the postural system and a second task could contribute to falls in older adults with poor balance. This study examined the attentional demands of balance recovery from a mild postural disturbance in balance-impaired elderly persons. A second purpose of this research was to determine the effect of performing a cognitive task on the recovery of balance in balance-impaired elderly persons. METHODS: Fifteen healthy older adults and 13 older adults with clinical balance impairment were exposed to balance disturbances by means of sudden movement of a platform on which they stood. A dual-task paradigm where postural recovery served as the primary task and verbal reaction time to auditory tones served as the secondary task was used to assess attentional demand. To determine the effect of the cognitive task on postural recovery, kinetic, kinematic, and neuromuscular measures of a feet-in-place response were investigated. RESULTS: Balance recovery using a feet-in-place response was attentionally demanding in both groups of older adults and was more demanding in balance-impaired than in healthy elderly persons. With the concurrent performance of a cognitive task, balance-impaired elderly persons took longer to stabilize their center of pressure and regain balance than in a single task, while healthy elderly persons showed no change between conditions. In addition, only balance-impaired elderly individuals had a greater center-of-pressure resultant velocity during recovery in a dual-task compared with a single-task situation. CONCLUSIONS: The ability to recover balance using a feet-in-place response was more attentionally demanding in balance-impaired than in healthy elderly persons. The recovery of balance was also slower and less efficient in balance-impaired elderly persons when simultaneously performing a cognitive task, whereas the ability of healthy elderly individuals to recover was not influenced by concurrent task demands. This suggests that dual-task performance may contribute to postural instability and falls in balance-impaired elderly individuals.

Predicting the probability for falls in community-dwelling older adults using the Timed Up & Go Test.

BACKGROUND AND PURPOSE: This study examined the sensitivity and specificity of the Timed Up & Go Test (TUG) under single-task versus dual-task conditions for identifying elderly individuals who are prone to falling. SUBJECTS: Fifteen older adults with no history of falls (mean age=78 years, SD=6, range=65-85) and 15 older adults with a history of 2 or more falls in the previous 6 months (mean age=86.2 years, SD=6, range=76-95) participated. METHODS: Time taken to complete the TUG under 3 conditions (TUG, TUG with a subtraction task [TUGcognitive], and TUG while carrying a full cup of water [TUGmanual]) was measured. A multivariate analysis of variance and discriminant function and logistic regression analyses were performed. RESULTS: The TUG was found to be a sensitive (sensitivity=87%) and specific (specificity=87%) measure for identifying elderly individuals who are prone to falls. For both groups of older adults, simultaneous performance of an additional task increased the time taken to complete the TUG, with the greatest effect in the older adults with a history of falls. The TUG scores with or without an additional task (cognitive or manual) were equivalent with respect to identifying fallers and nonfallers. CONCLUSION AND DISCUSSION: The results suggest that the TUG is a sensitive and specific measure for identifying community-dwelling adults who are at risk for falls. The ability to predict falls is not enhanced by adding a secondary task when performing the TUG.

Cognitive influence on postural stability: a neuromuscular analysis in young and older adults.

BACKGROUND: Previous literature indicates that attentional resources are required for recovery of postural stability. Previous studies have also examined the effect of aging on the performance of a static postural task while a secondary cognitive task is being conducted. This study describes the effect of a cognitive task on the neuromuscular response characteristics underlying reactive balance control in young versus older adults. METHODS: The attentional demand on the neuromuscular system was examined in 14 young and 12 healthy older adults by analysis of the integrated electromyography activity while the adults were performing a dual-task paradigm. The primary task involved standing platform perturbations and the secondary task was a math task that involved subtraction by threes. Integrated electromyography activity was compared between the cognitive (math and balance) task versus control (balance only) task. RESULTS: For both groups of subjects, onset latency of postural muscle responses did not change under dual-task conditions. In contrast, the amplitude of postural muscle activity was significantly affected by performance of a secondary task. When electromyography data were combined for both young and older adults, there was a decrease in muscle response amplitude in both agonist (gastrocnemius) and antagonist (tibialis anterior) muscles when the cognitive math task was performed. This was apparent at 350-500 milliseconds from plate onset for the gastrocnemius and between 150 and 500 for the tibialis anterior. When young and older adults were compared, an age by task interaction effect was seen in muscle response amplitude for the agonist (gastrocnemius) muscle between 350 to 500 milliseconds, with older adults showing a significantly greater reduction than young adults. CONCLUSION: The decline of muscle activity when the secondary task was performed suggests that less attentional processing capacity was available for balance control during the dual-task paradigm. The results also indicate that the dual-task activity has a greater impact on balance control in the older adults than in the young adults.

Attentional demands and postural control: the effect of sensory context.

BACKGROUND: This study used a dual task design to examine the effect of sensory context on postural stability during the concurrent performance of an attentionally demanding cognitive task in young and older adults with and without a history of imbalance and falls. METHODS: A choice reaction time auditory task was used to produce changes in attention during quiet stance in six different sensory conditions that changed the availability of accurate visual and somatosensory cues for postural control. Postural stability was quantified by using forceplate measures of center of pressure in 18 young adults, 18 healthy older adults, and 18 older adults with balance impairments and a history of recent falls. Reaction time and accuracy of verbal response to the auditory task were quantified by using a repeated measures analysis of variance. RESULTS: In young adults the auditory task did not affect postural stability in any of the sensory conditions. However, in the older adults the effect of the auditory task depended on sensory context. For healthy older adults, the addition of an auditory tone task significantly affected sway only when both visual and somatosensory cues for postural control were removed. In the balance-impaired older adults, the addition of the auditory task significantly affected postural stability in all sensory conditions. In addition, as sensory conditions became more difficult, older adults who had been able to maintain stability in a single task context lost balance when performing a secondary task. CONCLUSION: Results suggest that with aging, attentional demands for postural control increase as sensory information decreases. In addition, the inability to allocate sufficient attention to postural control under multitask conditions may be a contributing factor to imbalance and falls in some older adults.

Attentional demands and postural recovery: the effects of aging.

BACKGROUND: Cognitive demands associated with balance and locomotion may contribute to the incidence of falling among older adults. This study addressed issues related to the effects of aging on the attentional demands of recovering from an external disturbance to balance. This research also investigated whether performing a secondary cognitive task differentially affects postural recovery in young versus older adults. METHOD: Fifteen young and 10 healthy older adults were exposed to a series of balance disturbances. Attentional demands were assessed using a dual task paradigm where postural recovery served as the primary task, and counting backwards served as a concurrent secondary cognitive task. The effect of the counting task was assessed by comparing kinematic variables related to feet-in-place and stepping recovery strategies. RESULTS: Recovering upright stance was found to be attentionally demanding in both age groups. The type of recovery strategy did not influence attentional demands in young adults; however, a hierarchy of increasing attentional demands between the ankle strategy and compensatory stepping was apparent among older adults. In addition, stepping appears to be more attentionally demanding for older adults than for younger adults. Counting backwards did not affect the type of strategy used; however, it did affect the kinematics of stepping. For both age groups, steps occurred when the center of mass was located in a more central location within the base of support when the secondary task was added. CONCLUSIONS: The ability to recover a stable posture following an external perturbation is more attentionally demanding for older adults than for younger adults. This would suggest that for some older adults, an increased risk for loss of balance and falls may result if sufficient attentional resources are not allocated to the task of postural recovery.

Pallidotomy with the gamma knife: a positive experience.

51 patients with medically refractory Parkinson's disease underwent stereotactic posteromedial pallidotomy between August 1993 and February 1997 for treatment of bradykinesia, rigidity, and L-DOPA-induced dyskinesias. In 29 patients, the pallidotomies were performed with the Leksell Gamma Knife and in 22 they were performed with the standard radiofrequency (RF) method. Clinical assessment as well as blinded ratings of Unified Parkinson's Disease Rating Scale (UPDRS) scores were carried out pre- and postoperatively. Mean follow-up time is 20.6 months (range 6-48) and all except 4 patients have been followed more than one year. 85 percent of patients with dyskinesias were relieved of symptoms, regardless of whether the pallidotomies were performed with the Gamma Knife or radiofrequency methods. About 2/3 of the patients in both Gamma Knife and radiofrequency groups showed improvements in bradykinesia and rigidity, although when considered as a group neither the Gamma Knife nor the radiofrequency group showed statistically significant improvements in UPDRS scores. One patient in the Gamma Knife group (3.4%) developed a homonymous hemianopsia 9 months following treatment and 5 patients (27.7%) in the radiofrequency group became transiently confused postoperatively. No other complications were seen. Gamma Knife pallidotomy is as effective as radiofrequency pallidotomy in controlling certain of the symptoms of Parkinson's disease. It may be the only practical technique available in certain patients, such as those who take anticoagulants, have bleeding diatheses or serious systemic medical illnesses. It is a viable option for other patients as well.

Gamma knife radiosurgery as a lesioning technique in movement disorder surgery.

OBJECT: To increase knowledge of the safety and efficacy of the use of gamma knife radiosurgery in patients with movement disorders, the authors describe their own experience in this field and include blinded independent assessments of their results. METHODS: Fifty-five patients underwent radiosurgical placement of lesions either in the thalamus (27 patients) or globus pallidus (28 patients) for treatment of movement disorders. Patients were evaluated pre- and postoperatively by a team of observers skilled in the assessment of gait and movement disorders who were blinded to the procedure performed. The observers were not associated with the surgical team and concomitantly and blindly also assessed a group of 11 control patients with Parkinson's disease who did not undergo any surgical procedures. All stereotactic lesions were made with the Leksell gamma unit using the 4-mm secondary collimator helmet and a single isocenter with maximum doses from 120 to 160 Gy. Clinical follow-up evaluation indicated that 88% of patients who underwent thalamotomy became tremor free or nearly tremor free. Statistically significant improvements in performance were noted in the independent assessments of Unified Parkinson's Disease Rating Scale (UPDRS) scores in the patients undergoing thalamotomy. Of patients undergoing pallidotomy who had exhibited levodopainduced dyskinesias, 85.7% had total or near-total relief of that symptom. Clinical assessment indicated improvements in bradykinesia and rigidity in 64.3% of patients who underwent pallidotomy. Independent blinded assessments did not reveal statistically significant improvements in Hoehn and Yahr scores or UPDRS scores. On the other hand, 64.7% of patients showed improvements in subscores of the UPDRS, including activities of daily living (58%), total contralateral score (58%), and contralateral motor scores (47%). Total ipsilateral score and ipsilateral motor scores were both improved in 59% of patients. One (1.8%) of 55 patients experienced a homonymous hemianopsia 9 months after pallidotomy due to an unexpectedly large lesion. No other complications of any kind were seen. Neuropsychological test scores that were obtained for the combined pallidotomy and thalamotomy treatment groups preoperatively and at 6 months postoperatively demonstrated an absence of cognitive morbidity. Follow-up neuroimaging confirmed correct lesion location in all patients, with a mean maximum deviation from the planned target of 1 mm in the vertical axis. Measurements of lesions at regular intervals on postoperative magnetic resonance images demonstrated considerable variability in lesion volumes. The safety and efficacy of functional lesions made with the gamma knife appear to be similar to those made with the assistance of electrophysiological guidance with open functional stereotactic procedures. CONCLUSIONS: Functional lesions may be made safely and accurately using gamma knife radiosurgical techniques. The efficacy is equivalent to that reported for open techniques that use radiofrequency lesioning methods with electrophysiological guidance. Complications are very infrequent with the radiosurgical method. The use of functional radiosurgical lesioning to treat movement disorders is particularly attractive in older patients and in those with major systemic diseases or coagulopathies; its use in the general movement disorder population seems reasonable as well.

Predicting the probability for falls in community-dwelling older adults.

BACKGROUND AND PURPOSE: The objective of this retrospective case-control study was to develop a model for predicting the likelihood of falls among community-dwelling older adults. SUBJECTS: Forty-four community-dwelling adults (> or = 65 years of age) with and without a history of falls participated. METHODS: Subjects completed a health status questionnaire and underwent a clinical evaluation of balance and mobility function. Variables that differed between fallers and nonfallers were identified, using t tests and cross tabulation with chi-square tests. A forward stepwise regression analysis was carried out to identify a combination of variables that effectively predicted fall status. RESULTS: Five variables were found to be associated with fall history. These variables were analyzed using logistic regression. The final model combined the score on the Berg Balance Scale with a self-reported history of imbalance to predict fall risk. Sensitivity was 91%, and specificity was 82%. CONCLUSION AND DISCUSSION: A simple predictive model based on two risk factors can be used by physical therapists to quantify fall risk in community-dwelling older adults. Identification of patients with a high fall risk can lead to an appropriate referral into a fall prevention program. In addition, fall risk can be used to calculate change resulting from intervention.

The effects of two types of cognitive tasks on postural stability in older adults with and without a history of falls.

BACKGROUND: This study used a dual task design to investigate the effects of two different types of cognitive tasks on stability (as measured by center of pressure displacement) in young vs older adults with and without a history of falls. METHODS: Two secondary cognitive tasks, a sentence completion and a visual perceptual matching task, were used to produce changes in attention during quiet stance under flat vs compliant surface conditions in 20 healthy young adults, 20 healthy older adults, and 20 older adults with a history of imbalance and falls. Postural stability was quantified using forceplate measures of center of pressure (COP). Speed and accuracy of verbal response on the cognitive tasks were also quantified. RESULTS: During the simultaneous performance of a cognitive and postural task, decrements in performance were found in the postural stability measures rather than the cognitive measures for all three groups. While no differences were found between the young adults and the older healthy adults on the firm surface, no task condition, when task complexity was increased (either through the introduction of a secondary cognitive task, or a more challenging postural condition such as standing on the compliant surface), significant differences in postural stability between the two groups became apparent. In contrast to the young and healthy older adults, postural stability in older adults with a history of falls was significantly affected by both cognitive tasks. CONCLUSION: Results suggest that when postural stability is impaired, even relatively simple cognitive tasks can further impact balance. Results further suggest that the allocation of attention during the performance of concurrent tasks is complex; depending on many factors including the nature of both the cognitive and postural task, the goal of the subject and the instructions.

Postural perturbations: new insights for treatment of balance disorders.

This article reviews the neural control of posture as understood through studies of automatic responses to mechanical perturbations. Recent studies of responses to postural perturbations have provided a new view of how postural stability is controlled, and this view has profound implications for physical therapy practice. We discuss the implications for rehabilitation of balance disorders and demonstrate how an understanding of the specific systems underlying postural control can help to focus and enrich our therapeutic approaches. By understanding the basic systems underlying control of balance, such as strategy selection, rapid latencies, coordinated temporal spatial patterns, force control, and context-specific adaptations, therapists can focus their treatment on each patient's specific impairments. Research on postural responses to surface translations has shown that balance is not based on a fixed set of equilibrium reflexes but on a flexible, functional motor skill that can adapt with training and experience. More research is needed to determine the extent to which quantification of automatic postural responses has practical implications for predicting falls in patients with constraints in their postural control system.

Gamma knife radiosurgery as a lesioning technique in movement disorder surgery.

Fifty-five patients underwent radiosurgical placement of lesions either in the thalamus (27 patients) or globus pallidus (28 patients) for treatment of movement disorders. Patients were evaluated pre- and postoperatively by a team of observers skilled in the assessment of gait and movement disorders who were blinded to the procedure performed. They were not associated with the surgical team and concomitantly and blindly also assessed a group of 11 control patients with Parkinson's disease who did not undergo any surgical procedures. All stereotactic lesions were made with the Leksell gamma unit using the 4-mm secondary collimator helmet and a single isocenter with dose maximums from 120 to 160 Gy. Clinical follow-up evaluation indicated that 88% of patients who underwent thalamotomy became tremor free or nearly tremor free. Statistically significant improvements in performance were noted in the independent assessments of Unified Parkinson's Disease Rating Scale (UPDRS) scores in the patients undergoing thalamotomy. Eighty-five and seven-tenths percent of patients undergoing pallidotomy who had exhibited levodopa-induced dyskinesias had total or near-total relief of that symptom. Clinical assessment indicated improvement of bradykinesia and rigidity in 64.3% of patients who underwent pallidotomy. Independent blinded assessments did not reveal statistically significant improvements in Hoehn and Yahr scores or UPDRS scores. On the other hand, 64.7% of patients showed improvements in subscores of the UPDRS, including activities of daily living (58%), total contralateral score (58%), and contralateral motor scores (47%). Ipsilateral total UPDRS and ipsilateral motor scores were both improved in 59% of patients. One (1.8%) of 55 patients experienced a homonymous hemianopsia 9 months after pallidotomy due to an unexpectedly large lesion. No other complications of any kind were seen. Follow-up neuroimaging confirmed correct lesion location in all patients, with a mean maximum deviation from the planned target of 1 mm in the vertical axis. Measurements of lesions at regular interals on postoperative magnetic resonance images demonstrated considerable variability in lesion volumes. The safety and efficacy of functional lesions made with the gamma knife appear to be similar to those made with the assistance of electrophysiological guidance with open functional stereotactic procedures. Functional lesions may be made safely and accurately using gamma knife radiosurgical techniques. The efficacy is equivalent to that reported for open techniques that use radiofrequency lesioning methods with electrophysiological guidance. Complications are very infrequent with the radiosurgical method. The use of functional radiosurgical lesioning to treat movement disorders is particularly attractive in older patients and those with major systemic diseases or coagulopathies; its use in the general movement disorder population seems reasonable as well.

The effect of multidimensional exercises on balance, mobility, and fall risk in community-dwelling older adults.

BACKGROUND AND PURPOSE: This prospective clinical investigation examined the effects of a multidimensional exercise program on balance, mobility, and risk for falls in community-dwelling older adults with a history of falling. Factors used to predict adherence and a successful response to exercise were identified. SUBJECTS: A total of 105 community-dwelling older adults (> or = 65 years of age) with a history of two or more falls in the previous 6 months (no neurologic diagnosis) participated. They were classified into (1) a control group of fallers (n = 21), (2) a fully adherent exercise group (n = 52), and (3) a partially adherent exercise group (n = 32). METHODS: Following evaluation, each patient received an individualized exercise program addressing the impairments and functional disabilities identified during the assessment. The control group received no intervention. Changes in performance on five clinical tests of balance and mobility and fall risk were compared among groups. RESULTS: Both exercise groups scored better than the control group on all measures of balance and mobility. Although both exercise groups showed a reduction in fall risk compared with the control group, the greatest reduction was found in the fully adherent exercise group. Factors associated with successful response to exercise included degree of adherence to exercise program and pretest score on the Tinetti Mobility Assessment. CONCLUSION AND DISCUSSION: Exercise can improve balance and mobility function and reduce the likelihood for falls among community-dwelling older adults with a history of falling. The amount of exercise needed to achieve these results, however, could not be determined from this study.

Effects of vestibular rehabilitation on dizziness and imbalance.

Vestibular rehabilitation is a specific approach to physical therapy aimed at reducing dizziness and imbalance by facilitating central nervous system compensation for peripheral vestibular dysfunction. This article reports preliminary results of studies concerning the relative effectiveness of vestibular rehabilitation, general conditioning exercises, and vestibular suppressant medication on dizziness and imbalance in patients with chronic vestibular symptoms of at least 6 months duration. Patients with positional and/or movement-related dizziness and abnormal posturography were randomly assigned to the three treatment groups. Preliminary results suggest that although all three treatment approaches reduce dizziness, only vestibular rehabilitation also improves balance. This study takes the first step toward determining the efficacy of a specific exercise approach for reducing dizziness and imbalance in patients with chronic peripheral vestibular disorders.

Changes in posture control across the life span--a systems approach.

In this article, a systems approach to the development of posture control across the life span and its integration with voluntary tasks such as walking is described. Research shows a clear cephalocaudal gradient in the development of postural responses. Postural muscle synergies develop appropriate temporal organization through experience in each new level of postural skill development. Sensory inputs contributing to posture control influence postural responses very early in development, with responses being elicited by vision alone, or by somatosensory and vestibular cues in isolation. Studies of older adults indicate small, but significant, increases in onset latencies and disruptions in the temporal organization of postural muscle responses when subjects are given external threats to balance. In addition, older adults, like young children, use antagonist muscles more often in coactivation with agonist muscles. Older adults also have more difficulty balancing when sensory inputs are reduced experimentally or pathologically. Ankle dorsiflexor muscle weakness is also a factor in balance dysfunction in the older adult.

Rehabilitation strategies for patients with vestibular deficits.

This article presents rehabilitation strategies for treatment of patients with vestibular deficits. Vestibular rehabilitation is an exercise-based approach designed to maximize central nervous system compensation for vestibular pathology. This paper reviews the physiologic rationale for an exercise-based approach and discusses specific assessment and treatment techniques involved in a vestibular rehabilitation program.

Postural sway biofeedback: its effect on reestablishing stance stability in hemiplegic patients.

A static force plate system was used to examine postural sway characteristics in 16 hemiplegic patients and in 34 normal elderly subjects. The effectiveness of postural sway (center of pressure) biofeedback was compared to conventional physical therapy practices in reestablishing stance stability in hemiplegic patients. Postural sway abnormalities in hemiplegic patients included significant mean lateral displacement of sway towards the nonaffected leg and increased total sway area. Postural sway biofeedback was more effective than conventional physical therapy practices in reducing mean lateral displacement of sway. This was associated with increased loading of the affected leg. Posttreatment changes in total sway area were not significantly different between experimental and control groups.

Vestibular function and motor proficiency of children with impaired hearing, or with learning disability and motor impairments.

Vestibular status and motor proficiency of 30 hearing-impaired and 15 motor-impaired learning-disabled children were documented to determine whether vestibular loss can account for deficits in motor co-ordination. Vestibular loss was differentiated from sensory organization deficits by means of VOR and postural orientation test results, which were compared with those of 54 normal seven-to 12-year-olds. Reduced or absent vestibular function in 20 hearing-impaired children did not affect development of motor proficiency, except in specific balance activities. However, sensory organization deficits in the learning-disabled group and in three of the hearing-impaired children were associated with widespread deficits in motor proficiency.

A critical examination of vestibular function in motor-impaired learning-disabled children.

This study examined the role of the vestibular system in balance and coordination problems found in motor-impaired, learning-disabled (LD) children. Vestibulo-ocular reflex (VOR) and vestibulo-spinal tests (moving platform posturography) were performed on 15 learning disabled and 54 normal children. Twelve LD children had normal VOR scores suggesting normal peripheral vestibular inputs. All 15 LD children had abnormal posturography. Motor-impaired LD children could not appropriately integrate vestibular information with visual and somatosensory inputs for postural orientation. Results suggest that the best discriminator of abnormal sensorimotor function in LD children are posturography trials requiring orientation to gravity despite absent or inaccurate visual and somatosensory cues, rather than traditionally relied on VOR and Romberg tests.