Temporal gait variability is a critical parameter in patients with balance problems. Increased magnitude of temporal gait variability corresponds to a higher risk of falls. The purpose of this study was to investigate the influence of walking speed on temporal stride-to-stride variability in patients with cerebellar and vestibular deficits. A GAITRite system was used to analyze the gait of 40 patients with cerebellar ataxia, 22 patients with bilateral vestibular failure, and 51 healthy subjects over the entire range of the individual's speed capacity. The coefficient of variability of stride time was calculated for each walk. Temporal gait variability was increased in cerebellar patients and vestibular patients. The magnitude of this variability depended on walking speed in a disease-specific manner. In patients with cerebellar ataxia, variability was increased during slow (8.4 ± 5.3%, P < .01) and fast (7.9 ± 6.4%, P < .01) walking speed but was normal during preferred walking speed. This resulted in a speed-related U-shaped function of stride-time variability. Patients with vestibular failure had increased variability during slow walking (9.9 ± 4.3%, P < .01). During walking with medium and fast walking speed, stride time variability was normal. Minimal temporal gait variability appears to be attractive for the locomotor system in cerebellar patients because these patients preferred to walk at a velocity associated with minimal stride-time variability. In contrast to previous studies, vestibular patients accelerate rather than decelerate gait to achieve dynamic stability. This may be explained by reduced sensory integration during fast locomotion.

This study provides Class IV evidence that in patients with BVP, an imperceptible level of nGVS improves dynamic walking stability.

Falls are common in patients presenting to a dizziness unit. Those with central syndromes are at risk of recurrent and injurious falling. Fall rates and fear of falling should be assessed in balance disorders and used to guide the regimen of rehabilitation therapy. The identification of risk factors would help provide protective measures to these groups of patients.

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Phobic postural vertigo (PPV) is the most common cause of chronic dizziness in middle-aged patients. Many patients report symptoms involving gait. We investigated the gait performance and its relationship to the fear of falling and attention of PPV patients in a prospective study of 24 patients with PPV and 24 healthy subjects (HS) using a pressure-sensitive mat (GAITRite(®)). Subjects walked at three different speeds (slow, preferred, fast), both during cognitive dual tasks (DTc) and with eyes closed (EC). Falls efficacy and balance confidence were rated by the Falls Efficacy Scale-International (FES-I) and the Activities-specific Balance Confidence Scale (ABC). PPV patients walked slower, with reduced cadence (all p < 0.01), stride length (p < 0.05), and increased double support (p < 0.01) compared to HS. These changes correlated with FES-I (R = -0.528, p < 0.001) and ABC (R = 0.481, p < 0.01). Walking deterioration under DTc did not differ between PPV patients and HS, but patients showed a reduced cognitive processing speed (p < 0.05). When walking with EC, gait speed decreased more in PPV patients compared to HS (p < 0.05). Patients with PPV show gait changes which correlate with their fear of falling and balance confidence. Absent visual feedback leads to more pronounced gait deteriorations in PPV patients than in HS, indicating a higher reliance of patients on visual information during walking. These findings support the view that the gait characteristics of PPV can be attributed to an inadequate, cautious gait control.

No abstract

Falls are common in patients with cerebellar ataxia (CA). Identification of gait variables associated with a higher risk of falls allows us to detect fallers and initiate protective procedures early. Gait variability, which is increased in CA patients, is a good predictor of falls in elderly subjects and patients with neurodegenerative diseases. The relationship between gait variability and fall risk in patients with different cerebellar disorders was systematically investigated. A total of 48 patients with different cerebellar ataxia entities [adult-onset cerebellar atrophy (SAOA) (n = 23), unknown entity (n = 7), vascular (n = 5), post-cerebellitis (n = 6), congenital (n = 2), Louis-Bar syndrome (n = 2), ethyltoxic (n = 2) posttraumatic (n = 1)] were examined using a GAITRite® sensor mat. Spatial and temporal variability parameters were used for ANOVA testing and logistic regression models with categorized fall events as dependent variables. Gait variability in the fore-aft direction showed significant differences between the fall groups (p < 0.05-0.01). Model effects were highest for walking with slow speed (correct prediction 0.50-0.72). The speed-dependent integral of gait variability markers showed a higher discriminatory power (correct prediction 0.74-0.94). Gait variability is linked to the fall risk of patients with CA, slow walking and temporal gait variability being most relevant. The use of speed-dependent integrals of gait variability improves the accuracy of fall prediction. To predict fall risks in cerebellar ataxia, gait variability measurements made during slow walking should be included in a gait analysis procedure. The effects of speed-adjusted physiotherapeutic interventions have to be further investigated.

Phobic postural vertigo (PPV) is characterized by a subjective dizziness and postural imbalance. Changes in postural control strategy may cause the disturbed postural performance in PPV. A better understanding of the mechanisms behind this change in strategy is required to improve the diagnostic tools and therapeutic options for this prevalent disorder. Here we apply stabilogram diffusion analysis (SDA) to examine the characteristics and modes of interaction of open- and closed-loop processes that make up the postural control scheme in PPV. Twenty patients with PPV and 20 age-matched healthy controls were recorded on a stabilometer platform with eyes open and with eyes closed. Spatio-temporal changes of the center of pressure (CoP) displacement were analyzed by means of SDA and complementary CoP amplitude measures. (1) Open-loop control mechanisms in PPV were disturbed because of a higher diffusion activity (p < 0.001). (2) The interaction of open- and closed-loop processes was altered in that the sensory feedback threshold of the system was lowered (p = 0.010). These two changes were comparable to those observed in healthy subjects during more demanding balance conditions such as standing with eyes closed. These data indicate that subjective imbalance in PPV is associated with characteristic changes in the coordination of open- and closed-loop mechanisms of postural control. Patients with PPV use sensory feedback inadequately during undisturbed stance, and this impairs postural performance. These changes are compatible with higher levels of anti-gravity muscle activity and co-contraction during the conscious concentration on control of postural stability.