The purposes of the study was to evaluate an effect of increasing balance task demands and visual tracking task demands, on stability and visual tracking performances, with possibility of any interaction among them. Twenty healthy participants were asked to perform various visual tracking tasks, with different attentional demands, while standing on various support surfaces. Two-way analysis of variance (ANOVA) with repeated measure design was performed to estimate significant effect. Support surface properties showed significant effects on stability measures but no significant effect on visual tracking performances were noticed. Significant effect of increasing visual tracking task demands on visual tracking performances were found. However, increasing visual tracking task demand did not show any significant effect on stability measures. Significant interaction effect was also found between surface properties and visual tracking task demands for stability measures. In conclusion, increasing balance demands effect stability and increasing visual tracking demands effect visual tracking performances.

No description available.

This study aimed to determine whether the use of body weight (BWS) during overground ambulation leads to immediate improvements in the gait pattern. of stroke clients, and whether an overground support system is feasible for use as a gait training tool in this population. Fourteen subjects 3 to 18 weeks post stroke and with ambulatory capacity but mobility problem (timed-up-and-go score > 25 s) participated in the study. Subjects were instructed to walk over a distance of 7 m with 0% (full weight bearing), 15% or 30% BWS provided by an overhead suspension system. Ground reaction forces, body kinematics and temporal distance factors were recorded. Subjects demonstrated significant improvements in force generation during both the loading and push off phase of gait (p < 0.001) with increasing support. There were also significant improvements in trunk postural control as well as a decrease in cycle duration and total double support time. The results indicate that providing partial BWS during overground walking allows for the expression of an improved walking pattern in stroke clients. The system was well tolerated by all subjects during testing and indicates therefore that this system is feasible for use in retraining walking in stoke clients.

Non-synostotic occipital plagiocephaly (NSOP) is a term commonly used to describe asymmetry of the infant skull arising in the perinatal period. There is preliminary evidence in the literature suggesting that infants with NSOP may exhibit a motor delay. However, confirmation of this delay, as well as elucidation of the factors that may contribute to this delay have never been empirically determined using standard measures of motor performance. / The objective of this study was to compare motor skill acquisition of infants with NSOP to a matched group of normal healthy children. The results indicated that infants with NSOP are more likely to be delayed in the acquisition of early motor skills when compared to typically developing infants. This delay appears to be associated with a lack of exposure to the prone position while awake. Findings suggest that clinicians should assess the possibility of motor delays when evaluating these children.

The global objectives of this project were to refine and validate the content, and to obtain preliminary estimates of reliability for the STroke REhabilitation Assessment of Movement (STREAM). Two consensus panels, involving a total of twenty physical therapists, produced an intermediate test version of STREAM. Based on initial evaluations of internal consistency and reliability, items that were redundant, unrelated, and/or not reliably scored were eliminated. The final STREAM, with enhanced content validity, is made up of thirty items evaluating limb movements and basic mobility. Two reliability studies were conducted: (1) a direct observation of twenty stroke patients by pairs of raters in the clinical setting, and (2) two repeated ratings by twenty raters using videotaped assessments of four stroke patients. The STREAM demonstrated excellent internal consistency, inter- and intra-rater reliability, and is now ready for preliminary use in the clinical setting. The favorable results of this study indicate that further testing of the psychometric properties of the STREAM is warranted.

Idiopathic Parkinson's disease (IPD) is a severely disabling neurodegenerative disorder. The akinesia symptom dramatically alters the lifestyle of individuals with IPD. A within-subjects design was used to study the effects of sensory stimulation on akinesia. Twelve male, non-institutionalized parkinsonian subjects were tested. All demonstrated akinesia and were right-handed. Reaction time and movement time measures were recorded on an Apple 2e computer. The task entailed reached from a release switch to a target switch while three sensory stimuli (visual, auditory and concurrent visual and auditory) were used randomly during three different environmental conditions (open, physical constraint and stress). It was found that the concurrent use of visual and auditory stimuli in an open environmental condition significantly decreased the movement times and total reaction times. Therefore the use of sensory stimulation improves a reaching movement in subjects with IPD. The use of such stimuli would alter the person's disabilities and improve their functional status.

The purpose of the present study was to identify the muscle and kinematic parameters associated with the emergence of a skilled organization of landing from a jump in boys 7 years to 13 years of age. Jumps were videotaped (60Hz) in the right sagittal plane. The digitized coordinates of six landmarks were used to calculate the angular position, velocity, and acceleration parameters for the hip, knee, and ankle joints. Surface EMG signals were recorded for six muscles (Tibialis Anterior, Lateral Gastrocnemius, Soleus, Vastus Lateralis, Rectus Femoris, Biceps Femoris) to obtain the pattern of muscle onsets in anticipation for landing and the modulation of the muscle activity during the impact phase. / Subjects could be classified into three distinct groups based on the pattern of muscle onsets: the Proximal-distal group (PDS), the Transitional group (TS), and the Adult group (AS). The classification reflected a progression from a proximal-distal (PDS) to a distal-proximal (AS) organization of landing. At the muscular level, the progression was associated with: (1) an increased contribution of the ankle to the anticipatory control of landing; and (2) the modulation of muscle activity to reduce the impact ground reaction forces. The strongest kinematic correlates were associated with the increased ability: (1) to manage and organize motion-dependent torques; (2) to critically modulate the joint position in anticipation of landing, and (3) to utilize anticipatory muscle activity rather than biomechanical joint limits to manage the impact ground reaction forces.

The gait pattern during treadmill walking is comparable with overground walking in healthy subjects, but the effects due to the mode of walking in stroke subjects have not been established. Purpose. (1) To compare the maximum gait speed of stroke subjects walking on treadmill vs. the ground. (2) To estimate the temporal-distance determinants of the maximal gait speed. (3) To compare temporal distance factors and body kinematics of stroke subjects walking at comfortable vs. maximum speeds during the two modes of locomotion. Subjects. Ten subjects (aged 63 +/- 19 years) with a hemiparesis due to a stroke (<3 months) were tested. Methods. Subjects walked at comfortable and maximal speeds on the treadmill and overground, and gait outcomes were thus compared. Results. Overground walking resulted in higher maximal speeds, greater stride lengths and a lower cadence, as compared to treadmill. The comfortable gait speed and the maximum stride length proved to be strong determinants for the maximal speed on both modes of locomotion, but the maximum cadence was correlated to maximum speed only overground. At matched speed, the hip and knee joint demonstrated greater excursion overground for both the paretic and nonparetic sides. Conclusions. Stroke subjects walked slower on the treadmill as compared to overground. Furthermore, a different strategy was implemented to increase gait speed on each surface. A guarded gait pattern was evident in the lower extremity kinematic patterns during treadmill ambulation, perhaps due to muscle weakness, reduced stability and fear of falling on the treadmill.

The ability to pinch an object precisely is an essential function of the hand. The primary objective of this experiment was to examine the effect of aging on the perception of a pinch-grip force exerted by the thumb and index finger. Twelve young (25.3 +/- 2.4 yr.) and twelve older (71.4 +/- 3.3 yr.) healthy adults executed unilateral and bilateral pinch-grip tasks with and without visual feedback. The performance of the older group was worse than that of the younger individuals when asked to reproduce a pinch force. Specifically, the older adults tended to produce an initial overshoot in force which then decreased towards the required force. However, no difference existed between the two age groups when they were asked to produce a same force with both hands simultaneously. These results suggest that the normal aging process has a more significant effect on sensorimotor memory than on the output of descending motor commands.

Injury to the central nervous system as a result of cerebrovascular accidents (CVA) often leads to impairment in balance and mobility. Very little is known about the strategies that patients with CVA employ to prevent falls during unexpected changes of a support surface while patients are standing and walking. Previous studies showed that light touch increases postural stability in healthy subjects. However, it is not known whether patients with CVA would benefit from light touch in the same way as the healthy subjects do. Three studies in this research were conducted to examine the impact of stroke on postural responses triggered by surface rotations (Triggered Postural Responses; TPRs) during standing and walking and to investigate the effect of light touch on the control of TPRs during both tasks. Pitch and roll surface rotations (amplitude:5o; peak velocity:32o/s) were randomly presented to 11 stroke and 8 healthy age-matched subjects during quiet stance and walking, with similar limb geometry in double limb support. Light touch (<4N) was provided by a load sensor strip mounted on a rail along the walkway. Body kinematics was captured at 120 Hz by a 6-camera Vicon 512 system. Ground reaction forces were acquired at 1080Hz by 2 AMTI force plates. Surface EMGs were recorded at 1080 Hz from 4 bilateral lower limb muscles. Results showed that TPRs in healthy subjects were functionally appropriate to the direction of perturbations and task demands, such that TPRs were tuned down during walking, as compared to standing, suggesting that postural requirements are less during walking. In contrast, CVA disrupts equilibrium control such that TPRs in the stroke subjects were delayed and not modulated as the perturbed directions and task demands changed, possibly due to problems in sensorimotor integration. Asymmetry was characterized by under-activated muscle responses and force generations of the paretic side and hyperactivity of the non-paretic upper and lower extremit / Les lésions du système nerveux central suite à un accident vasculaire cérébral (AVC) affectent fréquemment l'équilibre et la mobilité. Peu d'information est disponible sur les stratégies utilisées par les patients ayant survécu à un AVC pour prévenir les chutes lorsque des changements inattendus de la surface de support se produisent pendant la marche et la position debout. Des études ont établi que des sujets sains voient leur stabilité posturale améliorée avec l'ajout d'information tactile. Cependant, il n'a pas été démontré si les sujets ayant eu un AVC peuvent aussi bénéficier de ces informations tactiles. Cette recherche inclut trois études visant à examiner, en premier lieu, l'impact d'un AVC sur les ajustements posturaux réactifs (APR) déclenchés par des rotations de la surface de support et, en deuxième lieu, l'effet des informations tactiles sur le contrôle de ces APR pendant deux tâches, soit la marche et la position debout. Onze sujets ayant eu un AVC et huit sujets sains, appariés pour le genre et l'âge, ont participé à ces études. Des rotations de la surface de support dans les plans sagittal et frontal (amplitude: 5°; vélocité maximale: 32°/s) étaient présentées aléatoirement aux sujets lors de la marche (phase de double appui) et en position debout (position des membres inférieurs simulant la phase de double appui). Le toucher léger (< 4N) d'une rampe fournissait l'information tactile aux sujets. Un système à six caméras d'analyse tridimensionnelle du mouvement (Vicon 512 system) a été utilisé pour acquérir les données cinématiques du corps à une fréquence de 120 Hz. L'électromyographie de surface de quatre muscles du membre inférieur a été enregistrée bilatéralement à une fréquence de 1080 Hz. Les forces de réaction du sol ont été acquises par deux plate-formes de force (AMTI) à la même fréquence. Les sujets sains ont présenté des APR fonctionnels et modulés par la directio