Monitoring gait at home with radio waves in Parkinson's disease: A marker of severity, progression, and medication response

Parkinson's disease (PD) is the fastest-growing neurological disease in the world. A key challenge in PD is tracking disease severity, progression, and medication response. Existing methods are semisubjective and require visiting the clinic. In this work, we demonstrate an effective approach for assessing PD severity, progression, and medication response at home, in an objective manner. We used a radio device located in the background of the home. The device detected and analyzed the radio waves that bounce off people's bodies and inferred their movements and gait speed. We continuously monitored 50 participants, with and without PD, in their homes for up to 1 year. We collected over 200,000 gait speed measurements. Cross-sectional analysis of the data shows that at-home gait speed strongly correlates with gold-standard PD assessments, as evaluated by the Movement Disorder Society-Sponsored Revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) part III subscore and total score. At-home gait speed also provides a more sensitive marker for tracking disease progression over time than the widely used MDS-UPDRS. Further, the monitored gait speed was able to capture symptom fluctuations in response to medications and their impact on patients' daily functioning. Our study shows the feasibility of continuous, objective, sensitive, and passive assessment of PD at home and hence has the potential of improving clinical care and drug clinical trials.

Physiotherapy versus Consecutive Physiotherapy and Cognitive Treatment in People with Parkinson's Disease: A Pilot Randomized Cross-Over Study

Background: Parkinson’s disease (PD) is characterized by motor and cognitive dysfunctions that can usually be treated by physiotherapy or cognitive training, respectively. The effects of consecutive physiotherapy and cognitive rehabilitation programs on PD deficits are less investigated. Objective: We investigated the effects of 3 months of physiotherapy (physiotherapy treatment group) or consecutive physiotherapy and cognitive (physiotherapy and cognitive treatment group) rehabilitation programs on cognitive, motor, and psychological aspects in 20 PD patients. Methods: The two groups switched programs and continued rehabilitation for another 3 months. The outcomes were score improvement on cognitive (Montreal Cognitive Assessment, Frontal Assessment Battery, Trail Making Test, Verbal Phonemic Fluency, Digit Span, and Rey Auditory Verbal Learning), motor (Unified Parkinson’s Disease Rating Scale-III, Berg Balance Scale, Two-Minute Walking Test, and Time Up and Go), and psychological (Beck Depression Inventory and State-Trait Anxiety Inventory) scales. Results: Between-group comparison revealed a significant difference in functional mobility between the two rehabilitation programs. Improvements in walking abilities were noted after both interventions, but only the patients treated with consecutive training showed better performance on functional mobility and memory tasks. Conclusion: Our findings support the hypothesis that consecutive physiotherapy plus cognitive rehabilitation may have a greater benefit than physiotherapy alone in patients with PD.

Survivors of Acute Lung Injury Have Greater Impairments in Strength and Exercise Capacity Than Survivors of Other Critical Illnesses as Measured Shortly After ICU Discharge

PURPOSE

To compare the physical function on ICU discharge in adults who survived an ICU admission for acute lung injury (ALI) with those admitted for a critical illness other than ALI.

MATERIALS AND METHODS

Two groups were recruited, (i) those who survived an ICU admission for ALI and, (ii) those who survived an ICU admission for a critical illness other than ALI. Within 7 days of discharge from ICU, in all participants, measures were collected of peripheral muscle strength, balance, walking speed and functional exercise capacity.

RESULTS

Recruitment was challenging and ceased prior to achieving the desired sample size. Participants with ALI (n = 22) and critical illness (n = 33) were of similar median age (50 vs. 57 yr, p = 0.09), sex proportion (males %, 45 vs. 58, p = 0.59) and median APACHE II score (21.5 vs. 23.0, p = 0.74). Compared with the participants with critical illness, those with ALI had lower hand grip (mean ± SD, 18 ± 9 vs. 13 ± 8 kg, p = 0.018) and shoulder flexion strength (10 ± 4 vs. 7 ± 3 kg, p = 0.047), slower 10-meter walk speed (median [IQR], 1.03 [0.78 to 1.14] vs. 0.78 [0.67 to 0.94] m/s, p = 0.039) and shorter 6-minute walk distance (265 [71 to 328] vs. 165 [53 to 220] m, p = 0.037). The Berg balance scores were similar in both groups.

CONCLUSIONS

Compared with survivors of a critical illness that is not ALI, those with ALI are likely to have greater physical impairment when measured shortly after discharge to the ward.

The Discriminative Power of Different Olfactory Domains in Parkinson's Disease

Background and Purpose: Olfactory dysfunction is one of the most common non-motor symptoms in Parkinson's disease (PD) preceding the motor symptoms for years. This study aimed to evaluate different olfactory domains in PD patients in comparison with healthy controls and to explore the relationships among olfactory deficit and other clinical manifestations in patients with PD.

Methods: Sniffin' Sticks test, which detects olfactory threshold, discrimination, and identification (TDI), were conducted in 500 PD patients and 115 controls. Furthermore, demographic and clinical data including motor and other non-motor symptoms were collected.

Results: In the single olfactory model, the identification test showed the area under the receiver operating characteristic (ROC) curve (AUC = 0.818), followed by threshold test (AUC = 0.731) and discrimination test (AUC = 0.723). Specifically, the identification test has a similar discriminative power as the TDI score (0.818 and 0.828, respectively, p = 0.481). In the integrated olfactory model involved with other non-motor manifestations, identification test scores performed as good as the TDI score in differentiating PD patients from controls (0.916 and 0.918, respectively, p = 0.797). In PD patients, age and cognition together explained 7.5% of the variance of the threshold score, while age, cognition, and gender accounted for the 15.2% explained variance of the discrimination score, while cognition, age, the ability of daily living, and gender together interpreted 11.1% of the variance of the identification score.

Conclusion: Our results indicated that the identification domain was the most practical olfactory factor in differentiating PD patients, and the combination of several different manifestations was better than a single symptom. Furthermore, the olfactory identification score may be associated with the ability of daily living.

Associations of Motor Symptom Severity and Quality of Life to Motor Task Performance in Upper and Lower Extremities Across Task Complexity in Parkinson's Disease

The authors examined the associations between the performance of upper- and lower-extremity motor tasks across task complexity and motor symptom severity, overall disease severity, and the physical aspects of quality of life in persons with Parkinson's disease. The performance was assessed for three lower-extremity tasks and two upper-extremity tasks of different levels of complexity. The motor symptoms and overall disease severity correlated significantly with all motor tasks with higher correlation coefficients in the complex tasks. Thus, the strength of the association between disease severity or severity of motor symptoms and motor performance is task-specific, with higher values in complex motor tasks than in simpler motor tasks. Mobility-related and activity-of-daily-living-related quality of life correlated with lower-extremity tasks of low and medium complexity and with the complex upper-extremity task, respectively; this suggests that Parkinson's Disease Questionnaire-39 is capable of differentiating between the impact of gross and fine motor function on quality of life.

Effects of inspiratory muscle training on respiratory muscle strength, lung function, functional capacity and cardiac autonomic function in Parkinson's disease: Randomized controlled clinical trial protocol

BACKGROUND

Individuals with Parkinson's disease (PD), in addition to motor impairment, may evolve with respiratory and autonomic nervous system disorders. Currently, there are few studies with emphasis on muscle and pulmonary dysfunction and that verify the benefits of inspiratory muscle training (IMT) in this population.

AIM

The aim of this study was to evaluate whether IMT is effective for the improvement of respiratory muscle strength, lung function, thoracic mobility, functional capacity and cardiac autonomic function in PD.

METHODS

A randomized and controlled trial will be conducted with 26 participants with idiopathic PD, with aged between 50 and 65 years, in the Stages I to III by the Modified Hoehn and Yahr Scale. Respiratory muscle strength will be performed by manovacuometry and lung function by spirometry. Functional capacity will be evaluated by the 6-min walk test and autonomic cardiac function by heart rate variability. In addition, thoracic mobility measurement will also be performed. After the evaluations, these participants will be randomly assigned to two groups: the IMT group with Powerbreathe^® , which will perform the eight series of 2 min each, with 1 min of rest between them, totaling 30 min, at 60% of the maximum inspiratory pressure and the control group, who will perform the same training protocol but with the load maintained at 9 cmH₂ O. All participants will be submitted to the same motor training protocol.

CONCLUSION

It is expected that IMT increases the inspiratory muscle strength, contributing to the improved expiratory muscle strength, lung function, thoracic mobility, functional capacity and cardiac autonomic function in individuals with mild to moderate PD.

The coefficient of friction in Parkinson's disease gait

This study aimed to characterize the coefficient of friction (COF) curves of patients with Parkinson's disease (PD) during barefoot gait and to evaluate the relationships between this variable and functional scales. Twenty-two subjects with PD (ON phase of levodopa) and 22 healthy subjects participated in this study. The participants walked barefoot along a pathway that went over two force plates embedded in the floor of the data collection room. The instantaneous COF was calculated as the ratio between the horizontal and vertical components of the ground reaction forces. Two-sample t-tests applied to every 1% of the support phase of the COF curve were used to compare the groups and to identify the phases in which the two groups were different. Specifically, three COF areas were computed: Area 1 (for the loading response phase), Area 2 (for the midstance phase) and Area 3 (for the terminal stance phase). Pearson's tests were applied to assess the associations between the COF curve areas and the clinical scales. The subjects with PD exhibited lower COF values during the loading response and terminal stance phases and higher COF values during the mid-stance phase compared with the control group. A strong positive correlation was observed between Area 1 and the Timed Up and Go Test (90.3%). In conclusion, the patients' COFs exhibited patterns that were different from those of the control group. Moreover, during the loading response phase, these differences were well-correlated with the Timed Up and Go Test scale data; Timed Up and Go Test data can be used to identify the risk of falls among PD patients.

Robot-assisted gait training versus treadmill training in patients with Parkinson's disease: a kinematic evaluation with gait profile score

The purpose of this study was to quantitatively compare the effects, on walking performance, of end-effector robotic rehabilitation locomotor training versus intensive training with a treadmill in Parkinson's disease (PD). Fifty patients with PD were randomly divided into two groups: 25 were assigned to the robot-assisted therapy group (RG) and 25 to the intensive treadmill therapy group (IG). They were evaluated with clinical examination and 3D quantitative gait analysis [gait profile score (GPS) and its constituent gait variable scores (GVSs) were calculated from gait analysis data] at the beginning (T0) and at the end (T1) of the treatment. In the RG no differences were found in the GPS, but there were significant improvements in some GVSs (Pelvic Obl and Hip Ab-Add). The IG showed no statistically significant changes in either GPS or GVSs. The end-effector robotic rehabilitation locomotor training improved gait kinematics and seems to be effective for rehabilitation in patients with mild PD.

Effects of treadmill training on cognitive and motor features of patients with mild to moderate Parkinson's disease: a pilot, single-blind, randomized controlled trial

The aim of this pilot randomized controlled trial was to evaluate the effects of treadmill training on cognitive and motor performance in patients with Parkinson's disease (PD). Seventeen persons with mild to moderate PD were enrolled. Nine patients were allocated to the Intervention group and received twelve 45-minute sessions of treadmill training: one session a day, three days a week, for four consecutive weeks. Eight patients were allocated to the Control group; these patients did not undergo physical training but were required to have regular social interactions, following a specific lifestyle program. All the patients were evaluated at baseline and one month later. The primary outcome measures were the Frontal Assessment Battery-Italian version (FAB-it) and the 6-minute walking test (6MWT). At the one month evaluation significant differences were found between the groups in their performance on the FAB-it (p=0.005) and the 6MWT (p=0.018). Our findings support the hypothesis that treadmill training might effectively improve cognitive and motor features in patients with PD.

Validation of Neuropsychological Tests to Screen for Dementia in Chinese Patients With Parkinson's Disease

To compare the accuracy of different neuropsychological tests and their combinations for deriving reliable cognitive indices for dementia diagnosis in Parkinson's disease (PD). One hundred forty consecutive patients with PD were recruited and administrated an extensive battery of neuropsychological tests. Discriminant analysis and receiver-operator characteristic curve were used to evaluate their correct classifications and validity. Patients with PD having dementia (PDD; 23.5%) performed significantly worse in all tests than patients without dementia. Age of onset, disease duration, Hoehn-Yahr grade, Unified Parkinson's Disease Rating Scale part III scores, and education were associated with dementia in patients with PD. Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment, and Block Design (BD) showed better specificity and sensitivity when used alone, and combined use of MMSE and BD further increased the validity. Our results indicated that the accuracy of MMSE was better in dementia diagnosis of Chinese patients with PD, and combined use of MMSE and BD could further increase the validity of dementia diagnosis.

Execution of Activities of Daily Living in Persons with Parkinson Disease

INTRODUCTION

Muscular weakness and the motor difficulties associated with Parkinson disease (PD) often impair the performance of activities of daily living (ADL). However, little is known about the magnitude and distribution of relative muscular effort of persons with PD during ADL. The purpose of this investigation was to determine the relative magnitude of lower extremity moment production that persons with PD use to perform common ADL.

METHODS

Fifteen participants with mild-to-moderate PD and 14 age/sex-matched controls volunteered. Participants performed a series of ADL tasks, as follows: gait initiation (GI), gait, and stair ascending tasks. Participants were then asked to perform maximal-effort isokinetic tests of hip and knee extension and ankle plantarflexion at speeds of 90° per second and 120° per second. Relative effort was quantified as a percentage of the maximal isokinetic value produced by a joint during performance of the ADL. Relative effort and peak isokinetic joint moments were analyzed using a mixed-model ANOVA with repeated measures. All other comparisons were evaluated using independent t-tests.

RESULTS

Persons with PD produced smaller ankle plantarflexion moment at both 90° per second and 120° per second (P < 0.05). Relative effort during GI (271% vs 189%, P < 0.05) and gait (270% vs 161%, P < 0.05) was significantly greater at the ankle in persons with PD. Contribution of the ankle to the support moment was lower in PD during stair ascending (24% vs 34%) and GI (63% vs 57%) compared with that in controls.

CONCLUSIONS

The reduced ankle moments during ADL are indicative of deficits in muscular capabilities in those with PD. Moreover, PD caused a redistribution of joint torques, such that PD participants used their hip extensors more and ankle plantarflexors less.

Body-Sensor-Network-Based Kinematic Characterization and Comparative Outlook of UPDRS Scoring in Leg Agility, Sit-to-Stand, and Gait Tasks in Parkinson's Disease

Recently, we have proposed a body-sensor-network-based approach, composed of a few body-worn wireless inertial nodes, for automatic assignment of Unified Parkinson's Disease Rating Scale (UPDRS) scores in the following tasks: Leg agility (LA), Sit-to-Stand (S2S), and Gait (G). Unlike our previous works and the majority of the published studies, where UPDRS tasks were the sole focus, in this paper, we carry out a comparative investigation of the LA, S2S, and G tasks. In particular, after providing an accurate description of the features identified for the kinematic characterization of the three tasks, we comment on the correlation between the most relevant kinematic parameters and the UPDRS scoring. We analyzed the performance achieved by the automatic UPDRS scoring system and compared the estimated UPDRS evaluation with the one performed by neurologists, showing that the proposed system compares favorably with typical interrater variability. We then investigated the correlations between the UPDRS scores assigned to the various tasks by both the neurologists and the automatic system. The results, based on a limited number of subjects with Parkinson's disease (PD) (34 patients, 47 clinical trials), show poor-to-moderate correlations between the UPDRS scores of different tasks, highlighting that the patients' motor performance may vary significantly from one task to another, since different tasks relate to different aspects of the disease. An aggregate UPDRS score is also considered as a concise parameter, which can provide additional information on the overall level of the motor impairments of a Parkinson's patient. Finally, we discuss a possible implementation of a practical e-health application for the remote monitoring of PD patients.

Relationship between Cognitive Performance and Motor Dysfunction in Patients with Parkinson's Disease: A Pilot Cross-Sectional Study

The aim of this pilot cross-sectional study was to extensively investigate the relationships between cognitive performance and motor dysfunction involving balance and gait ability in patients with Parkinson's disease. Twenty subjects with Parkinson's disease underwent a cognitive (outcomes: Frontal Assessment Battery-Italian version, Montreal overall Cognitive Assessment, Trail Making Test, Semantic Verbal Fluency Test, and Memory with Interference Test) and motor (outcomes: Berg Balance Scale, 10-Meter Walking Test, 6-Minute Walking Test, Timed Up and Go Test performed also under dual task condition, and Unified Parkinson's Disease Rating Scale) assessment. Our correlation analyses showed that balance skills are significantly correlated with executive functions, cognitive impairment, and ability to switch attention between two tasks. Furthermore, functional mobility showed a significant correlation with cognitive impairment, verbal fluency, and ability to switch attention between two tasks. In addition, the functional mobility evaluated under the dual task condition showed a significant correlation with cognitive impairment and ability to switch attention between two tasks. These findings might help early identification of cognitive deficits or motor dysfunctions in patients with Parkinson's disease who may benefit from rehabilitative strategies. Future prospective larger-scale studies are needed to strengthen our results.

Robot-assisted gait training is not superior to balance training for improving postural instability in patients with mild to moderate Parkinson’s disease: a single-blind randomized controlled trial

Objective:

The main aim was to compare robotic gait training vs. balance training for reducing postural instability in patients with Parkinson’s disease. The secondary aim was to compare their effects on the level of confidence during activities of daily living requiring balance, functional mobility and severity of disease.

Design:

Randomized controlled trial.

Setting:

University hospital.

Subjects:

A total of 66 patients with Parkinson’s disease at Hoehn and Yahr Stage 3.

Intervention:

After balanced randomization, all patients received 12, 45-minute treatment sessions, three days a week, for four consecutive weeks. A group underwent robot-assisted gait training with progressive gait speed increasing and body-weight support decreasing. The other group underwent balance training aimed at improving postural reactions (self and externally induced destabilization, coordination, locomotor dexterity exercises).

Main measures:

Patients were evaluated before, after and one month posttreatment. Main outcome measure: Berg Balance Scale. Secondary outcomes: Activities-Specific Balance Confidence Scale; Timed Up and Go Test; Unified Parkinson’s Disease Rating Scale.

Results:

No significant differences were found between the groups for the Berg Balance Scale either immediately after intervention (mean score in the robotic training group 51.58 ±3.94; mean score in the balance training group 51.15 ±3.46), or one-month follow-up (mean score in the robotic training group 51.03 ±4.63; mean score in the balance training group 50.97 ±4.28). Similar results were found for all the secondary outcome measures.

Conclusions:

Our findings indicate that robotic gait training is not superior to balance training for improving postural instability in patients with mild to moderate Parkinson’s disease.

Predictors of gait speeds and the relationship of gait speeds to falls in men and women with Parkinson disease

Gait difficulties and falls are commonly reported in people with Parkinson disease (PD). Reduction in gait speed is a major characteristic of Parkinsonian gait, yet little is known about its underlying determinants, its ability to reflect an internal reservation about walking, or its relationship to falls. To study these issues, we selected age, disease severity, and nonmotor factors (i.e., depression, quality of life, balance confidence, and exercise beliefs and attitudes) to predict self-selected (SELF), fast-as-possible (FAST), and the difference (DIFF) between these walking speeds in 78 individuals with PD. We also examined gender differences in gait speeds and evaluated how gait speeds were related to a retrospective fall report. Age, disease severity, and balance confidence were strong predictors of SELF, FAST, and, to a lesser extent, DIFF. All three parameters were strongly associated with falling. DIFF was significantly greater in men compared to women and was significantly associated with male but not female fallers. The results supported the clinical utility of using a suite of gait speed parameters to provide insight into the gait difficulties and differentiating between fallers in people with PD.

Robot-assisted walking training for individuals with Parkinson's disease: a pilot randomized controlled trial

BACKGROUND

Over the last years, the introduction of robotic technologies into Parkinson's disease rehabilitation settings has progressed from concept to reality. However, the benefit of robotic training remains elusive. This pilot randomized controlled observer trial is aimed at investigating the feasibility, the effectiveness and the efficacy of new end-effector robot training in people with mild Parkinson's disease.

METHODS

Design. Pilot randomized controlled trial.

RESULTS

Robot training was feasible, acceptable, safe, and the participants completed 100% of the prescribed training sessions. A statistically significant improvement in gait index was found in favour of the EG (T0 versus T1). In particular, the statistical analysis of primary outcome (gait speed) using the Friedman test showed statistically significant improvements for the EG (p = 0,0195). The statistical analysis performed by Friedman test of Step length left (p = 0,0195) and right (p = 0,0195) and Stride length left (p = 0,0078) and right (p = 0,0195) showed a significant statistical gain. No statistically significant improvements on the CG were found.

CONCLUSIONS

Robot training is a feasible and safe form of rehabilitative exercise for cognitively intact people with mild PD. This original approach can contribute to increase a short time lower limb motor recovery in idiopathic PD patients. The focus on the gait recovery is a further characteristic that makes this research relevant to clinical practice. On the whole, the simplicity of treatment, the lack of side effects, and the positive results from patients support the recommendation to extend the use of this treatment. Further investigation regarding the long-time effectiveness of robot training is warranted.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01668407.

Robot-assisted gait training versus equal intensity treadmill training in patients with mild to moderate Parkinson's disease: a randomized controlled trial

BACKGROUND

There is a lack of evidence about the most effective strategy for training gait in mild to moderate Parkinson's disease. The aim of this study was to compare the effects of robotic gait training versus equal intensity treadmill training and conventional physiotherapy on walking ability in patients with mild to moderate Parkinson's disease.

METHODS

Sixty patients with mild to moderate Parkinson's disease (Hoehn & Yahr stage 3) were randomly assigned into three groups. All patients received twelve, 45-min treatment sessions, three days a week, for four consecutive weeks. The Robotic Gait Training group (n = 20) underwent robot-assisted gait training. The Treadmill Training group (n = 20) performed equal intensity treadmill training without body-weight support. The Physical Therapy group (n = 20) underwent conventional gait therapy according to the proprioceptive neuromuscular facilitation concept. Patients were evaluated before, after and 3 months post-treatment. Primary outcomes were the following timed tasks: 10-m walking test, 6-min walking test.

RESULTS

No statistically significant difference was found on the primary outcome measures between the Robotic Gait Training group and the Treadmill Training group at the after treatment evaluation. A statistically significant improvement was found after treatment on the primary outcomes in favor of the Robotic Gait Training group and Treadmill Training group compared to the Physical Therapy group. Findings were confirmed at the 3-month follow-up evaluation.

CONCLUSIONS

Our findings support the hypothesis that robotic gait training is not superior to equal intensity treadmill training for improving walking ability in patients with mild to moderate Parkinson's disease.

Abnormalities and Cue Dependence of Rhythmical Upper-Limb Movements in Parkinson Patients With Freezing of Gait

Background. Freezing of gait (FOG) is a significant clinical problem in Parkinson disease (PD). Similar freezing-like episodes occur during finger movements, but little is known about ongoing motor problems during repetitive hand movements. Objective. To investigate if the regulation of bimanual movements is impaired in those with FOG and if withdrawal of an auditory cue amplifies this problem. Methods. A total of 23 PD patients (11 with and 12 without FOG) and 11 controls (CTRLs) performed repetitive finger movements, either externally paced or following cue withdrawal. Movement frequency, amplitude, and coordination pattern were manipulated. The stability and accuracy of movement were evaluated after exclusion of freezing trials. Results. With auditory pacing present, movement performance was comparable between groups. Following cue withdrawal, motor control deteriorated in those with FOG, resulting in smaller and less stable amplitudes, hastened and more variable frequency, and decreased coordination stability. Conversely, the performance of those without FOG remained mostly similar to that of CTRLs. Conclusions. Compared with those without FOG, those with FOG show greater continuous dyscontrol of bimanual movements, similar to the continuous timing and scaling difficulties during locomotion. Those with FOG also benefit from auditory cueing during upper-limb movements, but these are highly cue dependent. This implies that internal timekeeping functions are more disturbed in those with FOG, who may require rehabilitation strategies for repetitive upper-extremity tasks that include cueing and imagery.

Robot-assisted gait training in patients with Parkinson disease: a randomized controlled trial

BACKGROUND

. Gait impairment is a common cause of disability in Parkinson disease (PD). Electromechanical devices to assist stepping have been suggested as a potential intervention.

OBJECTIVE

. To evaluate whether a rehabilitation program of robot-assisted gait training (RAGT) is more effective than conventional physiotherapy to improve walking.

METHODS

. A total of 41 patients with PD were randomly assigned to 45-minute treatment sessions (12 in all), 3 days a week, for 4 consecutive weeks of either robotic stepper training (RST; n = 21) using the Gait Trainer or physiotherapy (PT; n = 20) with active joint mobilization and a modest amount of conventional gait training. Participants were evaluated before, immediately after, and 1 month after treatment. Primary outcomes were 10-m walking speed and distance walked in 6 minutes.

RESULTS

. Baseline measures revealed no statistical differences between groups, but the PT group walked 0.12 m/s slower; 5 patients withdrew. A statistically significant improvement was found in favor of the RST group (walking speed 1.22 ± 0.19 m/s [P = .035]; distance 366.06 ± 78.54 m [P < .001]) compared with the PT group (0.98 ± 0.32 m/s; 280.11 ± 106.61 m). The RAGT mean speed increased by 0.13 m/s, which is probably not clinically important. Improvements were maintained 1 month later.

CONCLUSIONS

. RAGT may improve aspects of walking ability in patients with PD. Future trials should compare robotic assistive training with treadmill or equal amounts of overground walking practice.

Quadriceps muscle weakness, activation deficits, and fatigue with Parkinson disease

BACKGROUND

People with Parkinson disease (PD) typically have complaints of weakness. The mechanisms underlying this deficit have not been well established, although many factors may contribute.

OBJECTIVE

This investigation aimed to characterize quadriceps muscle weakness and activation failure in people with PD and explore whether these deficits were related to disease severity. The authors further sought to examine quadriceps muscle fatigability.

METHODS

This was a cross-sectional comparison of 17 people with mild-severe PD and 17 healthy adults matched by age, sex, and body mass index (BMI). The Unified Parkinson's Disease Rating Scale motor score (UPDRS motor) ranged from 9.5 to 61.0. Participants were divided into those with low-PD motor signs (UPDRS motor < 31.7) and high-PD motor signs (UPDRS motor ≥ 31.7). Measures of quadriceps performance included isometric torque, central activation using doublet interpolation, and an isokinetic fatigue test.

RESULTS

Participants with high-PD motor signs had significantly more quadriceps weakness and central activation deficits than those with low-PD motor signs or healthy controls. Strength and activation deficits correlated strongly with UPDRS motor score. Quadriceps muscle fatigue was present in healthy controls and in those with low-PD motor signs but not in those with high-PD motor signs.

CONCLUSIONS

These findings provide additional evidence for lower-extremity strength loss with PD; central activation deficits may account for some of the strength deficits, especially with increased PD motor signs. Also, muscle fatigue did not occur in individuals with a greater degree of PD motor signs, most likely because of insufficient central activation to allow for muscle overload to induce metabolic fatigue.

Freezing of Gait in Parkinson Disease Is Associated With Impaired Conflict Resolution

Background. Freezing of gait (FOG) in Parkinson disease (PD) may involve executive dysfunction. This study examined whether executive functioning and attention are more affected in patients with FOG compared with those without and determined whether these processes are influenced by anti-Parkinson medication. Methods. A total of 11 PD patients with FOG, 11 without FOG, and 10 healthy control subjects, matched for age, gender, and education, participated. General motor, mental and cognitive screening tests, as well as specific neuropsychological assessment of executive functions and the Attention Network Test (ANT) were administered. The ANT was conducted in both ON and OFF phases in a counterbalanced design to determine medication-specific effects. Results. FOG showed a clear association with impairment in the executive control network for conflict resolution (inhibition of unwanted responses and impaired response selection), compared with nonfreezers and healthy controls, F(2, 28) = 5.41, P = .01. Orienting and alerting function did not differ between groups, F < 1. Other executive functions, such as abstract problem solving and mental flexibility were not associated with FOG ( P > .10). Anti-Parkinson medication did not ameliorate conflict resolution ( P > .10), although orienting attention improved with medication, F(1, 17) = 9.81, P < .01. Conclusions. This study shows an association between impaired conflict resolution and FOG, important in understanding the interplay between cognitive and motor problems, which can lead to specific rehabilitation strategies.

Effect of step training and rhythmic auditory stimulation on functional performance in Parkinson patients

BACKGROUND

Rhythmic auditory stimulation (RAS) can influence movement during straight line walking and direction transition in individuals with Parkinson disease (PD).

OBJECTIVE

The authors studied whether multidirectional step training with RAS would generalize to functional gait conditions used in daily activities and balance.

METHODS

In a matched-pairs design, 8 patients practiced externally paced (EP) stepping (RAS group), and 8 patients practiced internally paced (IP) stepping (no RAS group) for 6 weeks. Participants were evaluated on the first and last days of practice, and 1 week, 4 weeks, and 8 weeks after practice termination. Evaluations included a primary measurement--the Dynamic Gait Index (DGI)--and secondary measurements--the Unified Parkinson's Disease Rating Scale (UPDRS), Tinetti-gait and balance tests, Timed-Up-and-Go (TUG), and Freezing of Gait Questionnaire (FOGQ).

RESULTS

The RAS group significantly improved performance on the DGI and several secondary measures, and they maintained improvements for the DGI, Tinetti, FOGQ, and balance and gait items of the UPDRS above pretraining values at least 4 weeks after practice termination. The no RAS group revealed several improvements with training but could not maintain these improvements for as long as the other group.

CONCLUSIONS

Individuals with PD can generalize motor improvements achieved during multidirectional step training to contexts of functional gait and balance. Training with RAS is advantageous for enhancing functional gait improvements and the maintenance of functional gait and balance improvements over 8 weeks.

Effect of Balance Training on Postural Instability in Patients With Idiopathic Parkinson’s Disease

Background. Postural instability (PI) is a disabling sign of Parkinson’s disease (PD) not easily amenable to treatment with medication. Objective. To evaluate the effects of balance training on PI in patients with PD. Methods. A total of 64 patients with PI were randomly assigned to the experimental group (n = 33) for balance training or to the control group (n = 31) for general physical exercises. Each patient received 21 treatment sessions of 50 minutes each. Patients were evaluated by a blinded rater before and after treatment as well as 1 month posttreatment using the Berg Balance Scale (BBS), Activities-Specific Balance Confidence Scale (ABC), postural transfer test, self-destabilization of the center of foot pressure test, number of falls, Unified Parkinson’s Disease Rating Scale (UPDRS), modified Hoehn and Yahr (H&Y) Staging Scale, and Geriatric Depression Scale (GDS). Results .At the end of treatment, the experimental group showed significant improvements in all outcome measures, except for the UPDRS and the H&Y scale. Improvement was maintained at the 1-month follow-up in all outcome measures except for the GDS. No significant changes in performance were observed in the control group. Conclusions. A program of balance training can improve PI in patients with PD.

Knee extensor strength, dynamic stability, and functional ambulation: are they related in Parkinson's disease?

OBJECTIVE

To evaluate the relationship between knee extensor strength, postural stability, functional ambulation, and disease severity in Parkinson's disease (PD).

DESIGN

A cohort study.

SETTING

University research laboratory.

PARTICIPANTS

Patients (N=44) with idiopathic PD.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Participants were evaluated on their isokinetic knee extensor strength. Additionally, participants completed an assessment of their postural stability (Functional Reach Test for static stability and a dynamic postural stability assessment as measured by the center of pressure-center of mass moment arm during gait initiation). Participants also underwent an evaluation of their functional ambulation as measured by a 6-minute walk test. Lastly, participants were evaluated by a neurologist specially trained in movement disorders to assess neurologic status and disease severity using the Unified Parkinson's Disease Rating Scale and the Hoehn and Yahr disability score.

RESULTS

Knee extensor strength positively correlated with dynamic postural stability and negatively correlated with disease severity. Further, dynamic postural stability was negatively correlated to disease severity and positively correlated with functional ambulation in this cohort of patients with PD (P<.05). The results also suggest that the Functional Reach Test may be a valuable assessment tool to examine postural stability in PD.

CONCLUSIONS

These findings suggest a malleable relationship between knee extensor strength, dynamic stability, and disease severity in PD. Although strength is only one piece of the puzzle in the functional outcome of PD, these findings may assist clinicians in designing appropriate interventions aimed at increasing function and decreasing fall risk in PD.