Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0030567 (Parkinson's disease)
 63,064 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Motor and cognitive processes are required for successful 'real world' walking. We explored the specific contribution of motor function, executive function, and attention to functional gait performance in people with Parkinson's Disease (PD) when 'off' medication. Twenty-nine people with PD wearing an accelerometer were tested in their home whilst walking under four task conditions. Explanatory characteristics included age, motor function, executive function, sustained attention and divided attention. Repeated measures ANOVA compared gait speed under different task conditions. Multiple regression analysis explored the effect of characteristics on gait speed and gait interference (difference between dual and single task). Gait performance deteriorated under complex conditions (F=51.0, P<.001). Motor function and attention explained up to 65% variance in gait speed. Motor function, attention and executive function explained up to 66% variance in gait interference. Sustained attention explained up to 10% variance in gait speed; executive function explained up to 21% variance in gait interference and divided attention explained up to 22% variance in gait interference. Motor function, executive function and attention contribute to gait speed and gait interference in PD during a functional walking task whilst 'off' medication. When both executive function and attention are included as explanatory variables, attention discriminates gait performance more effectively. Whilst both contribute to functional gait, they are used selectively to optimise performance for different conditions and to meet complex task requirements.
Gait Posture 2010 Feb
PMID:Executive dysfunction and attention contribute to gait interference in 'off' state Parkinson's Disease. 1989 82

The later stages of Parkinson's disease (PD) are characterized by altered gait patterns. Although decreased arm swing during gait is the most frequently reported motor dysfunction in individuals with PD, quantitative descriptions of gait in early PD have largely ignored upper extremity movements. This study was designed to perform a quantitative analysis of arm swing magnitude and asymmetry that might be useful in the assessment of early PD. Twelve individuals with early PD (in "off" state) and eight controls underwent gait analysis using an optically-based motion capture system. Participants were instructed to walk at normal and fast velocities, and then on heels (to minimize push-off). Arm swing was measured as the excursion of the wrist with respect to the pelvis. Arm swing magnitude for each arm, and inter-arm asymmetry, were compared between groups. Both groups had comparable gait velocities (p = 0.61), and there was no significant difference between the groups in the magnitude of arm swing in all walking conditions for the arm that swung more (p = 0.907) or less (p = 0.080). Strikingly, the PD group showed significantly greater arm swing asymmetry (asymmetry angle: 13.9 + or - 7.9%) compared to the control group (asymmetry angle: 5.1 + or - 4.0%; p = 0.003). Unlike arm swing magnitude, arm swing asymmetry unequivocally differs between people with early PD and controls. Such quantitative evaluation of arm swing, especially its asymmetry, may have utility for early and differential diagnosis, and for tracking disease progression in patients with later PD.
Gait Posture 2010 Feb
PMID:Arm swing magnitude and asymmetry during gait in the early stages of Parkinson's disease. 1994 85

In speeding-up normal walking, relative phase between horizontal thorax and pelvis rotations changes from more in-phase (synchronous) to more out-of-phase. In pathology (stroke, Parkinson's disease, low-back pain, pregnancy-related pelvic girdle pain), this often fails to happen. Even in healthy gait, however, these phenomena remain poorly understood. Thorax-pelvis relative phase may increase with either stride length, or stride frequency. Sixteen healthy male subjects walked on a treadmill at 0.5m/s, 1.0m/s, or 1.5m/s, with small, normal, or large steps. Increasing stride length (with lower frequency) led to larger spinal rotations, larger thorax-pelvis relative phase, and lower pelvis-leg relative phase, while the thorax continued to counterrotate with respect to the leg. With small steps, speeding-up hardly affected thorax-pelvis relative phase, and spinal amplitudes remained low. From a certain walking speed onwards, pelvis rotations start to contribute to stride length, and thus to speed (the "pelvic step"). This phenomenon appears to be driven, and the present study suggests, at least for higher speeds, that also thoracic counterrotations are driven, and not determined by the passive dynamics of the system. For patients, several strategies may exist to avoid large thorax-pelvis relative phase, and the concomitant large rotations of the spine: walking slowly, walking with small steps, adapting the timing of thorax rotations to that of the pelvis, or refraining from adapting the timing of pelvis rotations to the movements of the leg.
Gait Posture 2010 Apr
PMID:The effects of stride length and stride frequency on trunk coordination in human walking. 2017 90

We conducted a 12-month longitudinal cohort study of 102 older people without dementia (52 Parkinson's Disease [PD]; 50 age- and sex-matched controls) to determine (1) if mild cognitive impairment predicts falls in older people with or without PD and (2) how baseline falls, a history of freezing and Hoehn and Yahr stage affected the association between cognitive impairment and multiple falls in PD patients. Cognitive impairment was defined as the sum of impairments on the caregiver-rated Clinical Dementia Rating Scale (CCDRSum>0). Overall the mean age (SD) was 71.5 (4.7) years, 42% were women, 26% had fallen and 14% had cognitive impairment at baseline. Thirty-one percent (15/52) of PD patients vs 12% (6/50) of controls fell more than once during 12-month follow-up, p=0.04. When combined in a 2-predictor model for the entire cohort, the adjusted odds ratios [aOR] for falling were significantly increased for cognitive impairment at baseline (aOR: 4.8, 95% CI: 1.3-18.2) and prior falls (aOR: 7.4, 95% CI: 2.4-22.3). The overall accuracy of the model was 82%, with low sensitivity of 19% but high specificity of 99%. In the PD subgroup, the overall accuracy of the same prediction model was 79%, with much better sensitivity of 73% but a lower specificity of 81%. We conclude that mild cognitive impairment might contribute to falls risk beyond conventional risk factors in older people with and without PD.
Gait Posture 2010 May
PMID:Relationship between mild cognitive impairment and falls in older people with and without Parkinson's disease: 1-Year Prospective Cohort Study. 2043 17

Patients with Parkinson's disease (PD) improve gait after treadmill training and while they are walking over the treadmill. However, the mechanisms of these improvements have not been addressed. We designed a treadmill simulator without a belt that could move on a walkway in a constant speed, in order to explore the mechanism underlying treadmill walking improvements in PD. All subjects were tested in three different sessions (treadmill, simulator(assisted) and simulator(not assisted)). In each session, subjects first walked overground and then walked using the treadmill or simulator with the hands over the handrails (simulator(assisted)) or with the hands free (simulator(not assisted)). Step length, cadence, double support time, swing time, support time and the coefficient of variation (CV) of step time and double support time were recorded. Over the treadmill PD patients increased their step length and reduced significantly their cadence and CV of double support time in comparison with overground walking. In the simulator(assisted) condition PD patients reduced significantly the CV of double support time in comparison with overground walking. With the simulator(not assisted) both groups decreased their step length and increased their cadence and CV of double support time, compared with walking overground. These findings suggest that the step length improvement observed in PD patients, walking over a treadmill, is due to the proprioceptive information generated by the belt movement, since no improvement was reported when patients using a treadmill simulator.
Gait Posture 2010 May
PMID:Mechanisms involved in treadmill walking improvements in Parkinson's disease. 2045 73

Asymmetry of symptoms of Parkinson's disease is clinically most evident for appendicular impairments. For axial impairments such as freezing of gait, asymmetry is less obvious. To date, asymmetries in balance control in PD patients have seldom been studied. Therefore, in this study we investigated whether postural control can be asymmetrically affected in mild to moderate PD patients. Seventeen PD patients were instructed to stand as still and symmetrically as possible on a dual force-plate during two trials. Dynamic postural asymmetry was assessed by comparing the centre-of-pressure velocities between both legs. Results showed that four patients (24%) had dynamic postural asymmetry, even after correcting for weight-bearing asymmetry. Hence, this study suggests that postural control can be asymmetrical in early PD. However, future studies should investigate the prevalence of dynamic postural asymmetry, in a larger group of PD patients. It should also be further investigated whether this approach can be used as a tool to support the initial diagnosis or monitor disease progression, or as an outcome measure for interventions aimed at improving balance in PD.
Gait Posture 2011 Jan
PMID:Assessment of postural asymmetry in mild to moderate Parkinson's disease. 2095 90

Previous research has shown that skill focused attention may be beneficial for the performance of complicated motor tasks in individuals with Parkinson's disease (PD). The objective of this study was to assess the impact of skill focused attention instructions on gait under temporal movement constraints that may reflect common challenges experienced in daily life. Eighteen patients with PD walked a straight pathway under two different attention focus conditions (no instruction, skill focused instruction) and two different walking speeds (preferred pace, as fast as possible). In the no instruction condition, patients were not told "where" attention should be directed. In the skill focused instruction condition, patients were told to focus on the foot contacting the floor with each step. Spatial and temporal gait measures, as well as, trunk sway were used to quantify walking performance. The results showed that when walking at a preferred pace, skill focused instructions benefited gait performance (e.g., increased gait velocity, larger steps, more trunk sway). However, when walking as fast as possible, skill focused instructions had the opposite effect on gait performance (e.g., decreased gait velocity, smaller steps, and less trunk sway). This study demonstrates that skill focused instructions may contribute to the prioritization of stability under imposed temporal movement constraints. Clinicians should be aware of the processes involved in prioritization of movement components versus task goals in PD and the potential application of an attention based instructional set in altering priorities in this population.
Gait Posture 2011 Jan
PMID:The effects of skill focused instructions on walking performance depend on movement constraints in Parkinson's disease. 2109 48

Previous studies have reported that patients with Parkinson's disease (PD) show, in the "off medication" state, a reduced activation of tibialis anterior (TA) in the late swing-early stance phase of the gait cycle. In PD patients the pathophysiological picture may cause differences among the stride cycles. Our aims were to evaluate how frequently TA activity is reduced in the late swing-early stance phase and if there is a relationship between the TA pattern and the clinical picture. Thirty PD patients were studied 2 h after Levodopa administration ("on-med") and 12 h after Levodopa wash-out ("off-med"). They were evaluated by the Unified Parkinson's Disease Rating Scale (UPDRS III) and surface electromyography of TA and gastrocnemius medialis (GM). The root mean square (RMS) of the TA activity in late swing-early stance phase (RMS-A) was normalized as a percent of the RMS of the TA activity in late stance-early swing (RMS-B). RMS-A was reduced in 30% of patients in the "off-med" condition. Within these patients, the percentage of stride cycles with reduced RMS-A, ranged between 28% and 83%. After Levodopa intake, no stride cycle showed reduced RMS-A. Patients with reduced RMS-A had a lower UPDRS III total score in the "on-med" rather than in the "off-med" condition (p=0.02). Our data confirm and extend previous observations indicating that, in "off-med" the function of TA is impaired in those patients clinically more responsive to Levodopa. TA activation is reduced in a relatively high percent of gait cycles in the "off-med" state. Since the variability of TA activation disappears after Levodopa administration, this phenomenon could be the expression of an abnormal dopaminergic drive.
Gait Posture 2011 Mar
PMID:Levodopa effect on electromyographic activation patterns of tibialis anterior muscle during walking in Parkinson's disease. 2125 51

Auditory and attentional cues improve gait in Parkinson disease (PD), but it is unclear if combining the two cueing strategies offers additional benefit. Further, the effect of a secondary cognitive task on cue efficacy is unknown. Therefore, this study aimed to assess the effects of cue type and task complexity on gait in PD. 11 participants with PD, 11 age-matched controls, and 11 young controls performed 3 walking trials on a GAITRite walkway under the following cueing conditions: no cue (baseline), rhythmic auditory cue at 10% below (AUD-10) and 10% above (AUD+10) self selected cadence, attentional cue (ATT; "take long strides"), and a combination of AUD and ATT (COM-10, COM+10). Each condition was also performed concurrently with a secondary word generation task (dual task, DT). Baseline gait velocity and stride length were less for those with PD and age-matched controls compared to young controls, and the ability of those with PD to use cues differed from the other groups. Gait velocity and stride length increased in PD with ATT, but not with auditory cues. Similar increases in gait velocity and stride length were observed with the combined cues, but additional benefit beyond ATT alone was not observed. Cues did not improve gait velocity during dual task walking, although stride length did increase with COMB+10. It appears persons with PD are able to benefit from attentional cueing and can combine attentional and auditory cues, but do not gain additional benefit from such a combination. During walking while performing a secondary cognitive task, attentional cues may help to facilitate a longer stride length.
Gait Posture 2011 Mar
PMID:The impact of attentional, auditory, and combined cues on walking during single and cognitive dual tasks in Parkinson disease. 2127 75

Posture analysis in quiet standing is a key component of the clinical evaluation of Parkinson's disease (PD), postural instability being one of PD's major symptoms. The aim of this study was to assess the feasibility of using accelerometers to characterize the postural behavior of early mild PD subjects. Twenty PD and 20 control subjects, wearing an accelerometer on the lower back, were tested in five conditions characterized by sensory and attentional perturbation. A total of 175 measures were computed from the signals to quantify tremor, acceleration, and displacement of body sway. Feature selection was implemented to identify the subsets of measures that better characterize the distinctive behavior of PD and control subjects. It was based on different classifiers and on a nested cross validation, to maximize robustness of selection with respect to changes in the training set. Several subsets of three features achieved misclassification rates as low as 5%. Many of them included a tremor-related measure, a postural measure in the frequency domain, and a postural displacement measure. Results suggest that quantitative posture analysis using a single accelerometer and a simple test protocol may provide useful information to characterize early PD subjects. This protocol is potentially usable to monitor the disease's progression.
 ...
PMID:Feature selection for accelerometer-based posture analysis in Parkinson's disease. 2134 95


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>