Henning Stolze

Falls in frequent neurological diseases--prevalence, risk factors and aetiology.

Abstract.The prevalence of falls among neurological patients is unknown, although disturbances of gait and posture are common. Falls may lead to burdens for the patient, the caregivers and the health system. We designed a prospective study and investigated all patients for a history of falls admitted to a neurological hospital during a 100-day period. Clinical investigation was carried out and several disease specific rating scales were applied. A total of 548 patients were investigated. Of all patients 34% had fallen once or more often during the last twelve months. A disturbance of gait was blamed for the fall in 55%, epileptic seizures in 12%, syncope in 10 % and stroke in 7%. Intrinsic risk factors for falls were high age, disturbed gait, poor balance and a fear of falling. As extrinsic factors we identified the treatment with antidepressants, neuroleptics and different cardiovascular medications, adverse environmental factors in the patients’ home and the use of walking aids. Within the diagnoses, falls were most frequent in Parkinson’s disease (62 %), syncope (57%) and polyneuropathy (48 %). According to these findings falls in neurological in-patients are twice as frequent as in an age-matched population living in the community. Falls in neurological patients are particularly linked to medication and disorders affecting gait and balance.

Comparative analysis of the gait disorder of normal pressure hydrocephalus and Parkinson's disease

OBJECTIVES Comparative gait analyses in neurological diseases interfering with locomotion are of particular interest, as many hypokinetic gait disorders have the same main features. The aim of the present study was (1) to compare the gait disturbance in normal pressure hydrocephalus and Parkinsons disease; (2) to evaluate which variables of the disturbed gait pattern respond to specific treatment in both diseases; and (3) to assess the responsiveness to visual and acoustic cues for gait improvement. METHODS In study 1 gait analysis was carried out on 11 patients with normal pressure hydrocephalus, 10 patients with Parkinsons disease, and 12 age matched healthy control subjects, on a walkway and on a treadmill. In study 2, patients with normal pressure hydrocephalus were reinvestigated after removal of 30 ml CSF, and patients with Parkinsons disease after administration of 150 mg levodopa. In part 3 visual cues were provided as stripes fixed on the walkway and acoustic cues as beats of a metronome. RESULTS The gait disorder in both diseases shared the feature of a reduced gait velocity, due to a diminished and highly variable stride length. Specific features of the gait disturbance in normal pressure hydrocephalus were a broad based gait pattern with outward rotated feet and a diminished height of the steps. After treatment in both diseases, the speed increased, due to an enlarged stride length, now presenting a lower variability. All other gait variables remained unaffected. External cues only mildly improved gait in normal pressure hydrocephalus, whereas they were highly effective in raising the stride length and cadence in Parkinsons disease. CONCLUSION The gait pattern in normal pressure hydrocephalus is clearly distinguishable from the gait of Parkinsons disease. As well as the basal ganglia output connections, other pathways and structures most likely in the frontal lobes are responsible for the gait pattern and especially the disturbed dynamic equilibrium in normal pressure hydrocephalus. Hypokinesia and its responsiveness to external cues in both diseases are assumed to be an expression of a disturbed motor planning.

Gait analysis during treadmill and overground locomotion in children and adults

Gait analysis on the treadmill and in the overground condition is used both in scientific approaches for investigating the neuronal organisation and ontogenetic development of locomotion and in a variety of clinical applications. We investigated the differences between overground and treadmill locomotion (at identical gait velocity) in 12 adults and 14 children (6-7 years old). During treadmill locomotion the step frequency increased by 7% in adults and 10% in children compared to overground walking, whereas the stride length and the stance phase of the walking cycle decreased. The swing phase, however, increased significantly by 5% in adults and remained unchanged in children. Balance-related gait parameters such as the step width and foot rotation angles increased during treadmill locomotion. The reduction of the step length was found to be stable after 10 min of treadmill walking in most subjects. With regard to the shifted phases of the walking cycle and the changed balance related gait parameters in the treadmill condition, we assume a different modulation of the central pattern generator in treadmill walking, due to a changed afferent input. Regarding the pronounced differences between overground and treadmill walking in children, it is discussed whether the systems generating and integrating different modulations of locomotion into a stable movement pattern have reached full capacity in 6-7 year old children.

Development of prehension movements in children: a kinematic study

Abstract To evaluate the normal development of functional hand motor skill, the kinematics of prehension movements were analyzed in 54 healthy children (age 4–12 years). The subjects repeatedly reached out for cylindrical target objects and grasped them with a precision grip of their dominant hand. The trajectory of the reaching hand and the finger aperture were monitored by optoelectronic motion analysis. To obtain comparable conditions for the different age groups, the experimental setup was scaled according to the individual body proportions of each subject. Within the investigated age range, neither the movement duration nor the normalized (according to body proportions) peak spatial velocity of the reaching hand changed significantly. However, the hand trajectory straightened and the coordination between hand transport and grip formation improved, resulting in smooth and stereotyped kinematic profiles at the age of 12 years. The younger children opened their grip relatively wider than the older ones, thus grasping with a higher safety margin. The dependence on visual control of the movement declined during motor development. Only the oldest childen were able to scale the grip aperture adequately, according to various sizes of the target objects, when visual control of the movement was lacking. The results suggest that the development of prehensile skills during childhood lasts until the end of the first decade of life. This functional maturation is discussed in relation to the development of neuronal pathways.

Typical features of cerebellar ataxic gait

Background: Although gait disturbance is one of the most pronounced and disabling symptoms in cerebellar disease (CD), quantitative studies on this topic are rare. Objectives: To characterise the typical clinical features of cerebellar gait and to analyse ataxia quantitatively. Methods: Twelve patients with various cerebellar disorders were compared with 12 age matched controls. Gait was analysed on a motor driven treadmill using a three dimensional system. A tandem gait paradigm was used to quantify gait ataxia. Results: For normal locomotion, a significantly reduced step frequency with a prolonged stance and double limb support duration was found in patients with CD. All gait measurements were highly variable in CD. Most importantly, balance related gait variables such as step width and foot rotation angles were increased in CD, indicating the need for stability during locomotion. The tandem gait paradigm showed typical features of cerebellar ataxia such as dysmetria, hypometria, hypermetria, and inappropriate timing of foot placement. Conclusions: Typical features of gait in CD are reduced cadence with increased balance related variables and an almost normal range of motion (with increased variability) in the joints of the lower extremity. The tandem gait paradigm accentuates all the features of gait ataxia and is the most sensitive clinical test.

Gait analysis in idiopathic normal pressure hydrocephalus – which parameters respond to the CSF tap test?

OBJECTIVES Normal pressure hydrocephalus (NPH) is an often underestimated cause of hypokinetic gait disorders in the elderly. Diagnosing NPH is a complex problem, since many symptoms overlap with other neurological diseases. The purpose of the present study was to characterize the gait pattern in NPH quantitatively. Additionally, we analyzed the improvement of gait parameters following tapping of cerebrospinal fluid (CSF). METHODS Gait analysis was performed in 10 patients and 12 age-matched healthy controls during overground and treadmill locomotion. RESULTS Compared to healthy controls, patients with NPH walked significantly slower, with shorter and more variable strides and a somewhat lower cadence. The feet were not lifted to a normal height and the dorsal extension of the forefoot prior to heel-strike was insufficient. Balance-related gait parameters such as step width and the foot rotation angles were significantly increased in NPH, while their variability was lower. Only some gait parameters improved after tapping 30 ml CSF. Gait velocity increased by about 23% due to an increased stride length, while the cadence remained unchanged. Balance-related gait parameters and the foot-to-floor clearance during swing were not affected by the treatment. CONCLUSIONS In conclusion, we found a triad of decreased stride length, decreased foot-to-floor clearance and a broad-based gait to be the typical features of the gait abnormality in NPH. Only the stride length improved following a diagnostic spinal tap. These results may help to more reliably diagnose the condition of NPH in a routine clinical setting.

Retest reliability of spatiotemporal gait parameters in children and adults

The objective of the study was to assess the retest-reliability of ten different gait parameters in healthy children (n=12; age 6-7 years) and adults (n=12; age 21-35 years) during free-speed locomotion on a simple walkway. Further the intra-subject variability of the stride dimensions was checked. On two occasions, spatial gait parameters were measured by footprint analysis, temporal dimensions were recorded using video-analysis. For spatial gait parameters, correlation coefficients (ICC, Pearsons r) between the test and the retest results were found to be high in adults and satisfying in children. The temporal parameters were less consistent. Generally the within-trial variability was higher in children than in adults. Conclusions: (i) The retest reliability for the measurement of the spatial gait parameters can be judged as high. (ii) For gait analysis in children it should be taken into account that gait parameters are more variable from trial to trial than in adults. Copyright 1997 Elsevier Science B.V.

Prevalence of gait disorders in hospitalized neurological patients

The prevalence of gait disorders among neurological inpatients is unknown, although disturbed gait is a common symptom. Gait disorders often lead to loss of independence with restraints for the patients and caregivers and costs for the health system. We designed a prospective study and investigated all patients admitted to a neurological hospital during a 100‐day period for the presence of a gait disorder. Clinical investigation and several disease‐specific rating scales were carried out for 493 patients. In 60% of the patients, a disturbance of gait was diagnosed. Most frequent diagnoses were stroke (21%), Parkinsons disease (17%), and polyneuropathy (7%). Within these diagnoses, the rate of patients with disturbed gait was high in Parkinsons disease (93%), subcortical arteriosclerotic encephalopathy (85%), and motor neuron disease (83%). Advanced age, dementia, alcohol abuse, and treatment with antiepileptics, neuroleptics, benzodiazepines, and chemotherapeutics were identified as risk factors for a gait disorder. A decline of cognitive function was accompanied by a reduction of walking speed. According to these results, gait disorders are among the most frequent symptoms in neurology.

Modulation of gait coordination by subthalamic stimulation improves freezing of gait

The effect of subthalamic deep brain stimulation on gait coordination and freezing of gait in patients with Parkinsons disease is incompletely understood. The purpose of this study was to investigate the extent to which modulation of symmetry and coordination between legs by subthalamic deep brain stimulation alters the frequency and duration of freezing of gait in patients with Parkinsons disease. We recruited 13 post‐subthalamic deep brain stimulation patients with Parkinsons disease with off freezing of gait and evaluated them in the following 4 conditions: subthalamic deep brain stimulation on (ON) and stimulation off (OFF), 50% reduction of stimulation voltage for the leg with shorter step length (worse side reduction) and for the leg with longer step length (better side reduction). Gait analysis was performed on a treadmill and recorded by an optoelectronic analysis system. We measured frequency and duration of freezing of gait episodes. Bilateral coordination of gait was assessed by the Phase Coordination Index, quantifying the ability to generate antiphase stepping. From the OFF to the ON state, freezing of gait improved in frequency (2.0 ± 0.4 to 1.4 ± 0.5 episodes) and duration (12.2 ± 2.6 to 2.6 ± 0.8 seconds; P = .005). Compared with the ON state, only better side reduction further reduced freezing of gait frequency (0.2 ± 0.2) and duration of episodes (0.2 ± 0.2 seconds; P = .03); worse side reduction did not change frequency (1.3 ± 0.4) but increased freezing of gait duration (5.2 ± 2.1 seconds). The better side reduction–associated improvements were accompanied by normalization of gait coordination, as measured by phase coordination index (16.5% ± 6.0%), which was significantly lower than in the other 3 conditions. Reduction of stimulation voltage in the side contralateral to the leg with longer step length improves frequency and duration of freezing of gait through normalization of gait symmetry and coordination in subthalamic deep brain stimulation patients with Parkinsons disease. This identifies poor leg coordination as a risk factor for causing freezing of gait.

Kinematic analysis of prehension movements in children

The kinematics of the reach-to-grasp movement were analyzed in ten healthy children (age 6-7 years) under different experimental conditions: distance and size of the target objects, and visual feedback during the reach were varied in a within-subjects design. To assess age-related differences, the same experiments were performed in ten healthy adults. The experimental set-up was scaled according to body proportions to obtain equivalent conditions for both age groups. The temporal coupling between the transport and grasp components of prehension was very similar in children and adults. Peak transport velocity increased by the same factor in both age groups when the object distance was doubled. However, the decelerating approach phase was shorter in the children, who opened their hands relatively wider than adults. Unlike the adults, children failed to scale their grip aperture according to object size when visual feedback during the movement was lacking. The grip aperture increased with object distance in adults, but not in the children. The intrasubject variability of kinematic parameters was distinctly higher in the children. The results suggest that grip formation is not yet mature at an age of 6-7 years, depending more on visual feedback than in adult prehension.