Ultrasonic motion analysis system - measurement of temporal and spatial gait parameters

The duration of stance and swing phase and step and stride length are important parameters in human gait. In this technical note a low-cost ultrasonic motion analysis system is described that is capable of measuring these temporal and spatial parameters while subjects walk on the floor. By using the propagation delay of sound when transmitted in air, this system is able to record the position of the subjects' feet. A small ultrasonic receiver is attached to both shoes of the subject while a transmitter is placed stationary on the floor. Four healthy subjects were used to test the device. Subtracting positions of the foot with zero velocity yielded step and stride length. The duration of stance and swing phase was calculated from heel-strike and toe-off. Comparison with data obtained from foot contact switches showed that applying two relative thresholds to the speed graph of the foot could reliably generate heel-strike and toe-off. Although the device is tested on healthy subjects in this study, it promises to be extremely valuable in examining pathological gait. When gait is asymmetrical, walking speed is not constant or when patients do not completely lift their feet, most existing devices will fail to correctly assess the proper gait parameters. Our device does not have this shortcoming and it will accurately demonstrate asymmetries and variations in the patient's gait. As an example, the recording of a left hemiplegic patient is presented in the discussion. (C) 2002 Elsevier Science Ltd. All rights reserved

The neural underpinnings of facial emotion recognition in ischemic stroke patients

Deficits in facial emotion recognition occur frequently after stroke, with adverse social and behavioural consequences. The aim of this study was to investigate the neural underpinnings of the recognition of emotional expressions, in particular of the distinct basic emotions (anger, disgust, fear, happiness, sadness and surprise). A group of 110 ischaemic stroke patients with lesions in (sub)cortical areas of the cerebrum was included. Emotion recognition was assessed with the Ekman 60 Faces Test of the FEEST. Patient data were compared to data of 162 matched healthy controls (HC’s). For the patients, whole brain voxel‐based lesion–symptom mapping (VLSM) on 3‐Tesla MRI images was performed. Results showed that patients performed significantly worse than HC’s on both overall recognition of emotions, and specifically of disgust, fear, sadness and surprise. VLSM showed significant lesion–symptom associations for FEEST total in the right fronto‐temporal region. Additionally, VLSM for the distinct emotions showed, apart from overlapping brain regions (insula, putamen and Rolandic operculum), also regions related to specific emotions. These were: middle and superior temporal gyrus (anger); caudate nucleus (disgust); superior corona radiate white matter tract, superior longitudinal fasciculus and middle frontal gyrus (happiness) and inferior frontal gyrus (sadness). Our findings help in understanding how lesions in specific brain regions can selectively affect the recognition of the basic emotions

Walking trajectory in neglect patients

A lateral deviation of the walking trajectory is often observed in stroke patients with unilateral spatial neglect. However, existing research appears to be contradictory regarding the direction of this deviation. The aim of the present study was to gain more insight into the walking trajectory of neglect patients. Twelve right hemisphere stroke patients (six neglect, six no neglect), eight left hemisphere stroke patients (none neglect) and 10 healthy control subjects were instructed to walk towards a target while a two-dimensional ultrasonic positioning system recorded their walking trajectory. Patients' recovery of walking ability was assessed and they were tested for the presence of neglect. Neglect patients showed a larger lateral deviation in their walking trajectory compared to stroke patients without neglect or controls. Neglect patients with good walking ability showed a deviation to the contralesional side. Neglect patients with limited walking ability showed a deviation to the ipsilesional side. Within the neglect group we found no relation between the severity of neglect and lateral deviation. Differences in walking ability may account for the contradictory results between studies regarding the lateral deviation in neglect patients' walking trajectory. We suggest that when a neglect patient's walking ability is limited, walking towards a target becomes a dual task: heading control and walking. A limited walking ability will cause a higher task priority of walking compared to heading control. This shift in task priority may be causing the change in walking trajectory deviation. (C) 2005 Elsevier B.V. All rights reserved

Effect of ageing on the ability to adapt to a visual distortion during walking

Degradation of major sensory systems such as proprioception, the vestibular system and vision may be a factor that contributes to the decline in walking stability in older people. In the present study this was examined by introducing a visual distortion by means of prism glasses shifting subject's view 10 degrees to the right while subjects walked towards a target (exposure condition). Shifting the view while walking towards a target will cause subjects to alter their heading in such a way that their walking trajectory describes a curvilinear path. It was expected that older people, when compared to young people, would have greater difficulty adjusting their heading and would show a greater decrease in heading stability, quantified by means of the standard deviation of the lateral position (SDLP). This was indeed the case. When performance in a pre- and post-exposure condition, in which subjects walked without prism glasses, were compared to each other, older people (O group) showed a greater decrease in heading stability than young people (Y group) and middle aged people (M group). Furthermore, it appeared that during the exposure condition adaptation effects were present in the Y and M group, which were absent in the O group. It is discussed that this adaptation is a form of realignment of the proprioceptive and visual system. The absence of realignment in the O group is argued to be caused by degradation of the proprioceptive system, which results in a lowering of the proprioceptive bias of vision

Functional recovery of gait and joint kinematics after right hemispheric stroke

OBJECTIVE: To gain insight into the relation between changes in gait patterns over time and functional recovery of walking ability in stroke patients. DESIGN: Cohort study. SETTING: Inpatient rehabilitation center of a university hospital in the Netherlands. PARTICIPANTS: Thirteen stroke patients admitted, or awaiting admission, for inpatient rehabilitation 3 weeks poststroke, and 16 healthy control subjects. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: At 3, 6, 12, 24, and 48 weeks poststroke, functional recovery of walking ability was assessed with the Rivermead Mobility Index (RMI) and the Functional Ambulation Categories (FAC). When possible, kinematics of the knee, hip, and pelvis were assessed through gait analysis in an 8 x 4 m gait laboratory. Minimal scores of 8 on the RMI and 4 on the FAC were necessary before patients were classified as functionally recovered. RESULTS: Patients whose joint kinematics during ambulation had recovered to within the range of the control group showed functional recovery of walking ability. However, some patients whose kinematics had developed toward an abnormal pattern also showed functional recovery. CONCLUSIONS: Recovery of joint kinematics toward a normal pattern is not required for functional recovery of walking ability. Early recognition of compensatory walking patterns that facilitate functional recovery may have implications for rehabilitation programs. Record 9 of 20 - MEDLINE(R) In-Process & Other Citations Dec Wk 4

The neural underpinnings of facial emotion recognition in ischemic stroke patients

Deficits in facial emotion recognition occur frequently after stroke, with adverse social and behavioural consequences. The aim of this study was to investigate the neural underpinnings of the recognition of emotional expressions, in particular of the distinct basic emotions (anger, disgust, fear, happiness, sadness and surprise). A group of 110 ischaemic stroke patients with lesions in (sub)cortical areas of the cerebrum was included. Emotion recognition was assessed with the Ekman 60 Faces Test of the FEEST. Patient data were compared to data of 162 matched healthy controls (HC's). For the patients, whole brain voxel-based lesion-symptom mapping (VLSM) on 3-Tesla MRI images was performed. Results showed that patients performed significantly worse than HC's on both overall recognition of emotions, and specifically of disgust, fear, sadness and surprise. VLSM showed significant lesion-symptom associations for FEEST total in the right fronto-temporal region. Additionally, VLSM for the distinct emotions showed, apart from overlapping brain regions (insula, putamen and Rolandic operculum), also regions related to specific emotions. These were: middle and superior temporal gyrus (anger); caudate nucleus (disgust); superior corona radiate white matter tract, superior longitudinal fasciculus and middle frontal gyrus (happiness) and inferior frontal gyrus (sadness). Our findings help in understanding how lesions in specific brain regions can selectively affect the recognition of the basic emotions