Sensory loss and walking speed related factors for gait alterations in patients with peripheral neuropathy

Gait Efficiency on an Uneven Surface Is Associated with Falls and Injury in Older Subjects with a Spectrum of Lower Limb Neuromuscular Function: A Prospective Study

OBJECTIVE

The objective of this study was to determine which gait measures on smooth and uneven surfaces predict falls and fall-related injuries in older subjects with diabetic peripheral neuropathy.

DESIGN

Twenty-seven subjects (12 women) with a spectrum of peripheral nerve function ranging from normal to moderately severe diabetic peripheral neuropathy walked on smooth and uneven surfaces, with gait parameters determined by optoelectronic kinematic techniques. Falls and injuries were then determined prospectively over the following year.

RESULTS

Seventeen subjects (62.9%) fell and 12 (44.4%) sustained a fall-related injury. As compared with nonfallers, the subject group reporting any fall, as well as the subject group reporting fall-related injury, demonstrated decreased speed, greater step width (SW), shorter step length (SL), and greater SW-to-SL ratio (SW:SL) on both surfaces. Uneven surface SW:SL was the strongest predictor of falls (pseudo-r = 0.65; P = 0.012) and remained so with inclusion of other relevant variables into the model. Post hoc analysis comparing injured with noninjured fallers showed no difference in any gait parameter.

CONCLUSION

SW:SL on an uneven surface is the strongest predictor of falls and injuries in older subjects with a spectrum of peripheral neurologic function. Given the relationship between SW:SL and efficiency, older neuropathic patients at increased fall risk appear to sacrifice efficiency for stability on uneven surfaces.

The interrelationship between disease severity, dynamic stability, and falls in cerebellar ataxia

Cerebellar ataxia (CA) results in discoordination of body movements (ataxia), a gait disorder, and falls. All three aspects appear to be obviously interrelated; however, experimental evidence is sparse. This study systematically correlated the clinical rating of the severity of ataxia with dynamic stability measures and the fall frequency in patients with CA. Clinical severity of CA in patients with sporadic (n = 34) and hereditary (n = 24) forms was assessed with the Scale for the Assessment and Rating of Ataxia (SARA). Gait performance was examined during slow, preferred, and maximally fast walking speeds. Spatiotemporal variability parameters in the fore-aft and medio-lateral directions were analyzed. The fall frequency was assessed using a standardized interview about fall events within the last 6 months. Fore-aft gait variability showed significant speed-dependent characteristics with highest magnitudes during slow and fast walking. The SARA score correlated positively with fore-aft gait variability, most prominently during fast walking. The fall frequency was significantly associated to fore-aft gait variability during slow walking. Severity of ataxia, dynamic stability, and the occurrence of falls were interrelated in a speed-dependent manner: (a) Severity of ataxia symptoms was closely related to instability during fast walking. (b) Fall frequency was associated with instability during slow walking. These findings suggest the presence of a speed-dependent, twofold cerebellar locomotor control. Assessment of gait performance during non-preferred, slow and fast walking speeds provides novel insights into the pathophysiology of cerebellar locomotor control and may become a useful approach in the clinical evaluation of patients with CA.

Noisy vestibular stimulation improves dynamic walking stability in bilateral vestibulopathy

OBJECTIVE

To examine the effects of imperceptible levels of white noise galvanic vestibular stimulation (nGVS) on dynamic walking stability in patients with bilateral vestibulopathy (BVP).

METHODS

Walking performance of 13 patients with confirmed BVP (mean age 50.1 ± 5.5 years) at slow, preferred, and fast speeds was examined during walking with zero-amplitude nGVS (sham trial) and nonzero-amplitude nGVS set to 80% of the individual cutaneous threshold for GVS (nGVS trial). Eight standard gait measures were analyzed: stride time, stride length, base of support, double support time percentage as well as the bilateral phase coordination index, and the coefficient of variation (CV) of stride time, stride length, and base of support.

RESULTS

Compared to the sham trial, nGVS improved stride time CV by 26.0% ± 8.4% (p < 0.041), stride length CV by 26.0% ± 7.7% (p < 0.029), base of support CV by 27.8% ± 2.9% (p < 0.037), and phase coordination index by 8.4% ± 8.8% (p < 0.013). The nGVS effects on walking performance were correlated with subjective ratings of walking balance (ρ = 0.79, p < 0.001). Effect of nGVS on walking stability was most pronounced during slow walking.

CONCLUSIONS

In patients with BVP, nGVS is effective in improving impaired gait performance, predominantly during slower walking speeds. It primarily targets the variability and bilateral coordination characteristics of the walking pattern, which are linked to dynamic walking stability. nGVS might present an effective treatment option to immediately improve walking performance and reduce the incidence of falls in patients with BVP.

CLASSIFICATION OF EVIDENCE

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

Vestibular asymmetry increases double support time variability in a counter-balanced study on elderly fallers

Vestibular asymmetry is a common cause of dizziness in the elderly, for whom it precipitates the risk of falling. Previous studies have shown that those with vestibular asymmetry displayed an altered variability in double support time (DST) compared to controls. However, swing time (SwT) variability findings are conflicting. In this study, we investigated if vestibular asymmetry might be causally connected to increased DST variability. We studied a group of eight elderly fallers with wrist fractures across three months, during which time four of them regained vestibular symmetry while four others developed an asymmetry. We evaluated the variability of DST and SwT, both when the participants suffered from vestibular asymmetry and when they did not. On average, variability in DST was significantly greater by 2.38%CV (coefficient of variation) when participants scored positive for vestibular asymmetry compared to when not, t(5)=4.39, p=0.01, ξ=1.67. In contrast, SwT variability differed non-significantly by 0.44%CV when participants had tested positive versus negative for vestibular asymmetry, t(5)=-0.87, p=0.39, ξ=-0.29. As a possible rationale for our results, we propose that increased DST variability may be the result of a re-stabilization strategy. Further research on DST variability and its correlation to the duration of vestibular asymmetry is recommended.

Gait Patterns in Children With Cancer and Vincristine Neuropathy

PURPOSE

Children treated with vincristine often develop chemotherapy-induced peripheral neuropathy (CIPN), but effects of CIPN on gait have not been reported.

METHODS

Gait variables of 52 children/adolescents treated for non-central nervous system cancers with CIPN were compared with an age- and sex-matched control group. Gait data were collected via GaitRite walkway before and after completing a 6-minute walk test (6MWT). Ankle range-of-motion (ROM) measures, balance, and strength tests were also completed.

RESULTS

Participants with CIPN had decreased velocity and step length. Ankle ROM and balance explained variability in step length. Both groups increased self-selected velocity after the 6MWT, but participants with cancer walked with slower velocity, shorter step length, and decreased cadence. Strength, neuropathy, and self-selected velocity measured before the 6MWT explained variability in 6MWT scores.

CONCLUSIONS

Ankle ROM and balance are important factors when treating step length deficits, whereas strength is also an important consideration for walking capacity.

Application of the clinical version of the narrow path walking test to identify elderly fallers

INTRODUCTION

Falling during walking is a common problem among the older population. Hence, the challenge facing clinicians is identifying who is at risk of falling during walking, for providing an effective intervention to reduce that risk. We aimed to assess whether the clinical version of the narrow path walking test (NPWT) could identify older adults who are reported falls.

MATERIALS AND METHODS

A total of 160 older adults were recruited and asked to recall fall events during the past year. Subjects were instructed to walk in the laboratory at a comfortable pace within a 6 meter long narrow path, 3 trials under single task (ST) and 3 trials dual task (DT) conditions without stepping outside the path (i.e., step errors). The average trial time, number of steps, trial velocity, number of step errors, and number of cognitive task errors were calculated for ST and DT. Fear of falling, performance oriented mobility assessment (POMA) and mini-metal state examination (MMSE) were measured as well.

RESULTS

Sixty-one subjects reported that they had fallen during the past year and 99 did not. Fallers performed more steps, and were slower than non-fallers. There were no significant differences, however, in the number of steps errors, the cognitive task errors in ST and DT in POMA and MMSE.

CONCLUSION

Our data demonstrates slower gait speed and more steps during the NPWT in ST and DT in fallers. There is no added value of DT over the ST for identification of faller's older adults.

Noise-Enhanced Vestibular Input Improves Dynamic Walking Stability in Healthy Subjects

BACKGROUND

White noise galvanic vestibular stimulation (GVS) is thought to enhance the sensitivity of vestibular organs.

OBJECTIVE

To examine the effects of noise-enhanced vestibular input on the walking performance in healthy subjects walking with eyes closed.

METHODS

Walking performance of 17 healthy subjects (mean age 28.8 ± 1.7 years) at slow, preferred, and fast speeds was examined during three different conditions: (1) walking with eyes open (EO) as baseline condition, (2) walking with eyes closed and sham noisy GVS (EC), and (3) walking with eyes closed and non-zero amplitude noisy GVS set to 80% of the individual sensory threshold for GVS (EC-GVS). Ten gait parameters were examined: stride time, stride length, base of support, swing time percentage, double support time percentage as well as gait asymmetry, bilateral phase coordination and the coefficient of variation (CV) of stride time, stride length and base of support.

RESULTS

Noisy GVS improved stride time CV by 36% (p < 0.034), stride length CV by 31% (p < 0.037), base of support CV by 14% (p < 0.009), and bilateral phase coordination by 23% (p < 0.034). The ameliorating effects of noisy GVS on locomotion function were primarily observable during slow walking speeds.

CONCLUSION

Noise-enhanced vestibular input is effective in improving locomotion function and is accompanied by a subjectively felt improvement of walking balance. It predominantly targets the variability and bilateral coordination characteristics of the walking pattern, which are critically linked to dynamic walking stability. Noisy GVS might present an effective treatment option to improve walking performance in patients with bilateral vestibular dysfunction.

Walking with Neuropathic Pain: Paradoxical Shift from Burden to Support?

Baclofen 5% cream can be used for the treatment of neuropathic pain. We describe an unusual case of a neuropathic pain patient with spinal cord injury. A 71-year-old woman with a partial spinal cord injury lesion at L4 complained of tingling, pins and needles, and burning in her legs. She scored her pain as 6 before adding baclofen 5% cream to her pain medication (pregabalin 450 mg, acetaminophen 3000 mg, and diclofenac 150 mg daily). One month later she experienced complete pain relief, though experienced increased difficulties in walking, leading to frequent falls. Her steadier walking without stumbling and falling was more important to her than pain reduction. Thus she decided to stop using baclofen. This unusual case report discusses two important issues that relate to pain medicine and rehabilitation in patients with painful spinal cord lesions: (1) the presence of wide areas of sensory loss “covered” by the presence of painful sensations and (2) pathological sensations that can be used and integrated in the body schema to create an improved spatiovisual orientation and thus mobility. Both these aspects have to be taken into account when treating pain and design rehabilitation programs.

Upper body kinematics in patients with cerebellar ataxia

Although abnormal oscillations of the trunk are a common clinical feature in patients with cerebellar ataxia, the kinematic behaviour of the upper body in ataxic patients has yet to be investigated in quantitative studies. In this study, an optoelectronic motion analysis system was used to measure the ranges of motion (ROMs) of the head and trunk segments in the sagittal, frontal and yaw planes in 16 patients with degenerative cerebellar ataxia during gait at self-selected speed. The data obtained were compared with those collected in a gender-, age- and gait speed-matched sample of healthy subjects and correlated with gait variables (time-distance means and coefficients of variation) and clinical variables (disease onset, duration and severity). The results showed significantly larger head and/or trunk ROMs in ataxic patients compared with controls in all three spatial planes, and significant correlations between trunk ROMs and disease duration and severity (in sagittal and frontal planes) and time-distance parameters (in the yaw plane), and between both head and trunk ROMs and swing phase duration variability (in the sagittal plane). Furthermore, the ataxic patients showed a flexed posture of both the head and the trunk during walking. In conclusion, our study revealed abnormal motor behaviour of the upper body in ataxic patients, mainly resulting in a flexed posture and larger oscillations of the head and trunk. The results of the correlation analyses suggest that the longer and more severe the disease, the larger the upper body oscillations and that large trunk oscillations may explain some aspects of gait variability. These results suggest the need of specific rehabilitation treatments or the use of elastic orthoses that may be particularly useful to reduce trunk oscillations and improve dynamic stability.

The spinal control of locomotion and step-to-step variability in left-right symmetry from slow to moderate speeds

When speed changes during locomotion, both temporal and spatial parameters of the pattern must adjust. Moreover, at slow speeds the step-to-step pattern becomes increasingly variable. The objectives of the present study were to assess if the spinal locomotor network adjusts both temporal and spatial parameters from slow to moderate stepping speeds and to determine if it contributes to step-to-step variability in left-right symmetry observed at slow speeds. To determine the role of the spinal locomotor network, the spinal cord of 6 adult cats was transected (spinalized) at low thoracic levels and the cats were trained to recover hindlimb locomotion. Cats were implanted with electrodes to chronically record electromyography (EMG) in several hindlimb muscles. Experiments began once a stable hindlimb locomotor pattern emerged. During experiments, EMG and bilateral video recordings were made during treadmill locomotion from 0.1 to 0.4 m/s in 0.05 m/s increments. Cycle and stance durations significantly decreased with increasing speed, whereas swing duration remained unaffected. Extensor burst duration significantly decreased with increasing speed, whereas sartorius burst duration remained unchanged. Stride length, step length, and the relative distance of the paw at stance offset significantly increased with increasing speed, whereas the relative distance at stance onset and both the temporal and spatial phasing between hindlimbs were unaffected. Both temporal and spatial step-to-step left-right asymmetry decreased with increasing speed. Therefore, the spinal cord is capable of adjusting both temporal and spatial parameters during treadmill locomotion, and it is responsible, at least in part, for the step-to-step variability in left-right symmetry observed at slow speeds.

[Gait disorders in geriatric patients. Classification and therapy]

BACKGROUND

Slow walking with reduced body dynamics is a characteristic feature of locomotion in the elderly. Impaired mobility and falls associated with gait disorders significantly contribute to a reduced quality of life in the elderly.

OBJECTIVES

A gait disorder is not an inevitable consequence of aging. This article shows that it is worth recognizing specific deficits and differentiating specific aspects in multifactorial disorders because many causes can be well treated. Also provided are the bases for clinical classification and therapeutic principles.

METHODS

Review of recent literature and clinical review based on own experience and own scientific results.

RESULTS

Common causes of disturbed gait in the elderly are neurological deficits, including sensory deficits (e.g. peripheral neuropathy and vestibulopathy), neurodegeneration (e.g. cerebellar ataxia and parkinsonian syndromes, cognitive impairment (e.g. degenerative dementia), degeneration of joints (e.g. coxarthrosis) and general loss of muscle mass (sarcopenia). Furthermore, a fear of falling also contributes to the gait disorder. Multimodal therapies are often necessary and the principles are presented.

CONCLUSION

Identification of deficits is a prerequisite for specific therapy. As physical activity protects against cognitive impairment, reduces the risk of falling and improves overall quality of life, a structured assessment of causes for gait impairment is crucial.

Increased double support variability in elderly female fallers with vestibular asymmetry

There is a broad consensus on the coupling of deteriorating gait and vestibular asymmetry, which has proved predictive of falls in the elderly. To date, research on this coupling remains inconclusive and has not focused specifically on fallers. In the present study, differences in gait variability were examined in a population of elderly females with fall-related wrist fractures, divided into samples with positive (N=28, 73±9 years) and negative head-shaking tests (N=6, 67±9 years). Swing, stance, and double support time variability were measured in preferred speed walking using GAITRite(®) and statistically evaluated in multivariate analysis of covariance with age as covariate. Results showed overall greater gait variability for the positive nystagmus group (p=0.03) despite non-significant adjustment of the covariate (p=0.18). In post-hoc analysis, the effect on variability in double support time emerged as a significant and large contributor to this difference (p=0.009, ηp(2)=0.20). Conversely, the ability of swing and stance time variability to discriminate between groups was both non-significant and small (p=0.25, ηp(2)=0.04 and p=0.34, ηp(2)=0.03 respectively). We believe that the increased variability might stem from a strategic use of double support to re-stabilize from balance perturbations during gait. To some extent, these results diverge from previous findings and need to be reassessed in future studies.

Quantification of gait changes in subjects with visual height intolerance when exposed to heights

Introduction: Visual height intolerance (vHI) manifests as instability at heights with apprehension of losing balance or falling. We investigated contributions of visual feedback and attention on gait performance of subjects with vHI.

Materials and Methods: Sixteen subjects with vHI walked over a gait mat (GAITRite®) on a 15-m-high balcony and at ground-level. Subjects walked at different speeds (slow, preferred, fast), during changes of the visual input (gaze straight/up/down; eyes open/closed), and while doing a cognitive task. An rmANOVA with the factors “height situation” and “gait condition” was performed. Subjects were also asked to estimate the height of the balcony over ground level. The individual estimates were used for correlations with the gait parameters.

Results: Study participants walked slower at heights, with reduced cadence and stride length. The double support phases were increased (all p < 0.01), which correlated with the estimated height of the balcony (R² = 0.453, p < 0.05). These changes were still present when walking with upward gaze or closure of the eyes. Under the conditions walking and looking down to the floor of the balcony, during dual-task and fast walking, there were no differences between the gait performance on the balcony and at ground-level.

Discussion: The found gait changes are features of a cautious gait control. Internal, cognitive models with anxiety play an important role for vHI; gait was similarly affected when the visual perception of the depth was prevented. Improvement by dual task at heights may be associated by a reduction of the anxiety level.

Conclusion: It is conceivable that mental distraction by dual task or increasing the walking speed might be useful recommendations to reduce the imbalance during locomotion in subjects susceptible to vHI.

A shoe insole delivering subsensory vibratory noise improves balance and gait in healthy elderly people

OBJECTIVES

To test whether subsensory vibratory noise applied to the sole of the foot using a novel piezoelectric vibratory insole can significantly improve sensation, enhance balance, and reduce gait variability in elderly people, as well as to determine the optimal level of vibratory noise and whether the therapeutic effect would endure and the user's sensory threshold would remain constant during the course of a day.

DESIGN

A randomized, single-blind, crossover study of 3 subsensory noise stimulation levels on 3 days.

SETTING

Balance and gait laboratory.

PARTICIPANTS

Healthy community-dwelling elderly volunteers (N=12; age, 65-90y) who could feel the maximum insole vibration.

INTERVENTIONS

A urethane foam insole with the piezoelectric actuators delivering subsensory vibratory noise stimulation to the soles of the feet.

MAIN OUTCOME MEASURES

Balance, gait, and timed Up and Go (TUG) test.

RESULTS

The vibratory insoles significantly improved performance on the TUG test, reduced the area of postural sway, and reduced the temporal variability of walking at both 70% and 85% of the sensory threshold and during the course of a day. Vibratory sensation thresholds remained relatively stable within and across study days.

CONCLUSIONS

This study provides proof of concept that the application of the principle of stochastic resonance to the foot sole sensory system using a new low-voltage piezoelectric technology can improve measures of balance and gait that are associated with falls. Effective vibratory noise amplitudes range from 70% to 85% of the sensory threshold and can be set once daily.

Diabetic foot and exercise therapy: step by step the role of rigid posture and biomechanics treatment

Lower extremity ulcers represent a serious and costly complication of diabetes mellitus. Many factors contribute to the development of diabetic foot. Peripheral neuropathy and peripheral vascular disease are the main causes of foot ulceration and contribute in turn to the growth of additional risk factors such as limited joint mobility, muscular alterations and foot deformities. Moreover, a deficit of balance, posture and biomechanics can be present, in particular in patients at high risk for ulceration. The result of this process may be the development of a vicious cycle which leads to abnormal distribution of the foot's plantar pressures in static and dynamic postural conditions. This review shows that some of these risk factors significantly improve after a few weeks of exercise therapy (ET) intervention. Accordingly it has been suggested that ET can be an important weapon in the prevention of foot ulcer. The aim of ET can relate to one or more alterations typically found in diabetic patients, although greater attention should be paid to the evaluation and possible correction of body balance, rigid posture and biomechanics. Some of the most important limitations of ET are difficult access to therapy, patient compliance and the transitoriness of the results if the training stops. Many proposals have been made to overcome such limitations. In particular, it is important that specialized centers offer the opportunity to participate in ET and during the treatment the team should work to change the patient's lifestyle by improving the execution of appropriate daily physical activity.