Temporal variability of gait in Parkinson disease: effects of a rehabilitation programme based on rhythmic sound cues

Impaired movement timing in neurological disorders: rehabilitation and treatment strategies

Timing abnormalities have been reported in many neurological disorders, including Parkinson's disease (PD). In PD, motor-timing impairments are especially debilitating in gait. Despite impaired audiomotor synchronization, PD patients' gait improves when they walk with an auditory metronome or with music. Building on that research, we make recommendations for optimizing sensory cues to improve the efficacy of rhythmic cuing in gait rehabilitation. Adaptive rhythmic metronomes (that synchronize with the patient's walking) might be especially effective. In a recent study we showed that adaptive metronomes synchronized consistently with PD patients' footsteps without requiring attention; this improved stability and reinstated healthy gait dynamics. Other strategies could help optimize sensory cues for gait rehabilitation. Groove music strongly engages the motor system and induces movement; bass-frequency tones are associated with movement and provide strong timing cues. Thus, groove and bass-frequency pulses could deliver potent rhythmic cues. These strategies capitalize on the close neural connections between auditory and motor networks; and auditory cues are typically preferred. However, moving visual cues greatly improve visuomotor synchronization and could warrant examination in gait rehabilitation. Together, a treatment approach that employs groove, auditory, bass-frequency, and adaptive (GABA) cues could help optimize rhythmic sensory cues for treating motor and timing deficits.

Automaticity of walking: functional significance, mechanisms, measurement and rehabilitation strategies

Automaticity is a hallmark feature of walking in adults who are healthy and well-functioning. In the context of walking, “automaticity” refers to the ability of the nervous system to successfully control typical steady state walking with minimal use of attention-demanding executive control resources. Converging lines of evidence indicate that walking deficits and disorders are characterized in part by a shift in the locomotor control strategy from healthy automaticity to compensatory executive control. This is potentially detrimental to walking performance, as an executive control strategy is not optimized for locomotor control. Furthermore, it places excessive demands on a limited pool of executive reserves. The result is compromised ability to perform basic and complex walking tasks and heightened risk for adverse mobility outcomes including falls. Strategies for rehabilitation of automaticity are not well defined, which is due to both a lack of systematic research into the causes of impaired automaticity and to a lack of robust neurophysiological assessments by which to gauge automaticity. These gaps in knowledge are concerning given the serious functional implications of compromised automaticity. Therefore, the objective of this article is to advance the science of automaticity of walking by consolidating evidence and identifying gaps in knowledge regarding: (a) functional significance of automaticity; (b) neurophysiology of automaticity; (c) measurement of automaticity; (d) mechanistic factors that compromise automaticity; and (e) strategies for rehabilitation of automaticity.

Musical training as an alternative and effective method for neuro-education and neuro-rehabilitation

In the last decade, important advances in the field of cognitive science, psychology, and neuroscience have largely contributed to improve our knowledge on brain functioning. More recently, a line of research has been developed that aims at using musical training and practice as alternative tools for boosting specific perceptual, motor, cognitive, and emotional skills both in healthy population and in neurologic patients. These findings are of great hope for a better treatment of language-based learning disorders or motor impairment in chronic non-communicative diseases. In the first part of this review, we highlight several studies showing that learning to play a musical instrument can induce substantial neuroplastic changes in cortical and subcortical regions of motor, auditory and speech processing networks in healthy population. In a second part, we provide an overview of the evidence showing that musical training can be an alternative, low-cost and effective method for the treatment of language-based learning impaired populations. We then report results of the few studies showing that training with musical instruments can have positive effects on motor, emotional, and cognitive deficits observed in patients with non-communicable diseases such as stroke or Parkinson Disease. Despite inherent differences between musical training in educational and rehabilitation contexts, these results favor the idea that the structural, multimodal, and emotional properties of musical training can play an important role in developing new, creative and cost-effective intervention programs for education and rehabilitation in the next future.

Individual musical tempo preference correlates with EEG beta rhythm

Every individual has a preferred musical tempo, which peaks slightly above 120 beats per minute and is subject to interindividual variation. The preferred tempo is believed to be associated with rhythmic body movements as well as motor cortex activity. However, a long-standing question is whether preferred tempo is determined biologically. To uncover the neural correlates of preferred tempo, we first determined an individual's preferred tempo using a multistep procedure. Subsequently, we correlated the preferred tempo with a general EEG timing parameter as well as perceptual and motor EEG correlates-namely, individual alpha frequency, auditory evoked gamma band response, and motor beta activity. Results showed a significant relation between preferred tempo and the frequency of motor beta activity. These findings suggest that individual tempo preferences result from neural activity in the motor cortex, explaining the interindividual variation.

Effects of physical activity in Parkinson's disease: A new tool for rehabilitation

Parkinson’s disease (PD) is a common neurodegenerative disease characterized by bradykinesia, tremor, rigidity, and postural instability. Motor disorders are composite and combined, adversely affecting the patient’s health. Tremor and rigidity are correlated with worsening manual dexterity as well as postural changes such as akinesia and camptocormia. Moreover, gait alteration as well as postural instability, with consequent impairment in balance, increase the risk of falls. It is well known that these symptoms respond poorly to pharmacologic therapy in PD patients. Physical therapy is the most effective non-pharmacological aid to PD patients. Available data in the literature indicate that any rehabilitation protocol has to focus on: cognitive movement strategies, cueing strategies, and improved physical capacity and balance. Different training programs for PD patients have been designed and evaluated but only specific training strategies, tailored and individualized for each patient, may produce improvements in gait speed and stride length, decrease motor and balance symptoms and improve quality of life. Furthermore, aerobic training may improve muscle trophism, strength and mobility. It seems reasonable to state that tailored physical activity is a valid tool to be included in the therapeutic program of PD patients, considering that this approach may ameliorate the symptoms as well as the overall physical incapacity, reduce the risk of falls and injuries, and ultimately improve quality of life.

A little elastic for a better performance: kinesiotaping of the motor effector modulates neural mechanisms for rhythmic movements

A rhythmic motor performance is brought about by an integration of timing information with movements. Investigations on the millisecond time scale distinguish two forms of time control, event-based timing and emergent timing. While event-based timing asserts the existence of a central internal timekeeper for the control of repetitive movements, the emergent timing perspective claims that timing emerges from dynamic control of nontemporal movements parameters. We have recently demonstrated that the precision of an isochronous performance, defined as performance of repeated movements having a uniform duration, was insensible to auditory stimuli of various characteristics (Bravi et al., 2014). Such finding has led us to investigate whether the application of an elastic therapeutic tape (Kinesio® Tex taping; KTT) used for treating athletic injuries and a variety of physical disorders, is able to reduce the timing variability of repetitive rhythmic movement. Young healthy subjects, tested with and without KTT, have participated in sessions in which sets of repeated isochronous wrist's flexion-extensions (IWFEs) were performed under various auditory conditions and during their recall. Kinematics was recorded and temporal parameters were extracted and analyzed. Our results show that the application of KTT decreases the variability of rhythmic movements by a 2-fold effect: on the one hand KTT provides extra proprioceptive information activating cutaneous mechanoreceptors, on the other KTT biases toward the emergent timing thus modulating the processes for rhythmic movements. Therefore, KTT appears able to render movements less audio dependent by relieving, at least partially, the central structures from time control and making available more resources for an augmented performance.

Fractal gait patterns are retained after entrainment to a fractal stimulus

Previous work has shown that fractal patterns in gait can be altered by entraining to a fractal stimulus. However, little is understood about how long those patterns are retained or which factors may influence stronger entrainment or retention. In experiment one, participants walked on a treadmill for 45 continuous minutes, which was separated into three phases. The first 15 minutes (pre-synchronization phase) consisted of walking without a fractal stimulus, the second 15 minutes consisted of walking while entraining to a fractal visual stimulus (synchronization phase), and the last 15 minutes (post-synchronization phase) consisted of walking without the stimulus to determine if the patterns adopted from the stimulus were retained. Fractal gait patterns were strengthened during the synchronization phase and were retained in the post-synchronization phase. In experiment two, similar methods were used to compare a continuous fractal stimulus to a discrete fractal stimulus to determine which stimulus type led to more persistent fractal gait patterns in the synchronization and post-synchronization (i.e., retention) phases. Both stimulus types led to equally persistent patterns in the synchronization phase, but only the discrete fractal stimulus led to retention of the patterns. The results add to the growing body of literature showing that fractal gait patterns can be manipulated in a predictable manner. Further, our results add to the literature by showing that the newly adopted gait patterns are retained for up to 15 minutes after entrainment and showed that a discrete visual stimulus is a better method to influence retention.

Characteristics of stride behavior during treadmill walking and stationary stepping

Much has been learned about the characteristics of gait in overground and treadmill walking. However, there are many contexts in which overground or treadmill walking might not be possible, such as in home-based physical therapy. In those cases, a surrogate task to index gait behavior would be a valuable tool. Thus, the purpose of this study was to evaluate the stride behavior characteristics of stationary stepping compared with treadmill walking. Healthy young adults (N = 10) preformed two 15-minute tasks: (1) treadmill walking and (2) stationary stepping. Several stride behavior characteristics were recorded, including the number of strides taken, minimum and maximum knee angle, stride interval mean, stride interval standard deviation, and detrended fluctuation analysis (DFA) alpha of the stride interval time series. The results showed that stride behavior was similar between tasks when examined at the group level. However, when individual level analyses were used to examine the reliability of each metric between tasks, poor reliability was observed in most metrics, indicating that stationary stepping may not be an appropriate surrogate task for overground or treadmill walking. These results are discussed in the context of a gait dynamics framework, with attention to task constraints that may have influenced the findings.

A wearable system for gait training in subjects with Parkinson's disease

In this paper, a system for gait training and rehabilitation for Parkinson's disease (PD) patients in a daily life setting is presented. It is based on a wearable architecture aimed at the provision of real-time auditory feedback. Recent studies have, in fact, shown that PD patients can receive benefit from a motor therapy based on auditory cueing and feedback, as happens in traditional rehabilitation contexts with verbal instructions given by clinical operators. To this extent, a system based on a wireless body sensor network and a smartphone has been developed. The system enables real-time extraction of gait spatio-temporal features and their comparison with a patient's reference walking parameters captured in the lab under clinical operator supervision. Feedback is returned to the user in form of vocal messages, encouraging the user to keep her/his walking behavior or to correct it. This paper describes the overall concept, the proposed usage scenario and the parameters estimated for the gait analysis. It also presents, in detail, the hardware-software architecture of the system and the evaluation of system reliability by testing it on a few subjects.

Modulation of isochronous movements in a flexible environment: links between motion and auditory experience

The ability to perform isochronous movements while listening to a rhythmic auditory stimulus requires a flexible process that integrates timing information with movement. Here, we explored how non-temporal and temporal characteristics of an auditory stimulus (presence, interval occupancy, and tempo) affect motor performance. These characteristics were chosen on the basis of their ability to modulate the precision and accuracy of synchronized movements. Subjects have participated in sessions in which they performed sets of repeated isochronous wrist's flexion-extensions under various conditions. The conditions were chosen on the basis of the defined characteristics. Kinematic parameters were evaluated during each session, and temporal parameters were analyzed. In order to study the effects of the auditory stimulus, we have minimized all other sensory information that could interfere with its perception or affect the performance of repeated isochronous movements. The present study shows that the distinct characteristics of an auditory stimulus significantly influence isochronous movements by altering their duration. Results provide evidence for an adaptable control of timing in the audio-motor coupling for isochronous movements. This flexibility would make plausible the use of different encoding strategies to adapt audio-motor coupling for specific tasks.

Effects of using the nintendo wii fit plus platform in the sensorimotor training of gait disorders in Parkinson's disease

The use of the Nintendo Wii has been considered a good alternative in the motor rehabilitation of individuals with Parkinson’s disease (PD), requiring simultaneous interaction to develop strategies for physical, visual, auditory, cognitive, psychological and social activities in the performing of virtual activities, resulting in improvement in functional performance and gait. The aim of this study was to analyze the effect of virtual sensorimotor activity on gait disorders in people with PD. Fifteen subjects with a clinical diagnosis of PD were submitted to the Unified Parkinson’s Disease Rating Scale (UPDRS III), Schwab and England Activities of Daily Living Scale (SE), Functional Independence Measure (FIM), and biomechanical gait analysis using digital images taken with a video camera before and after the treatment program. The activities with the Nintendo Wii virtual platform were standardized into three categories: aerobics, balance and Wii plus exercises. Participants carried out separate virtual exercises for 40 min, twice a week, for a total of 14 sessions. The program improved sensorimotor performance in PD gait, with an increase in stride length and gait speed, in addition to a reduction in motor impairment, especially in items of rigidity and flexibility of the lower limbs evaluated by UPDRS III, and greater functional independence, as evidenced in the SE and FIM scales. Improvements in items related to locomotion and stair climbing were also observed. The training was effective in motor recovery in chronic neurodegenerative diseases, showing improvement in motor performance and functional independence in individuals with PD.

Parkinson’s disease management strategies

Parkinson's disease (PD) treatment strategies should consider each patient individually. Drug therapy is the mainstay of treatment. An average 62-year-old male first diagnosed with PD will likely live for 20 years and treatment should be geared for long-term control of symptoms and quality of life. Of the currently available drugs, none are neurotoxic to the human substantia nigra and none are neuroprotective. As PD is a progressive disorder, all drugs have adverse effects and reduced efficacy with time. PD patients need regular follow-ups to make necessary medication adjustments. There is no perfect treatment. The authors have discussed their treatment methods and the reasoning behind it. Depending on the patient's age, the predominant symptoms and quality of life, treatment is individualized. In an average patient the least potent drugs, such as anticholinergics or amantadine, are administered first adding a dopamine agonist later on. Levodopa (LD) remains the most useful drug for PD and is reserved for later stages of disease. The objective is to keep the patient at Hoehn and Yahr Stage 2.0 or lower level of disability (bilateral findings with preserved postural reflexes) during off-stage and to avoid adverse effects. There is no long-term difference between standard preparations and control release formulations of LD/carbidopa or LD/benserazide. In older subjects, the first choice is LD. In patients who cannot be managed medically, surgical treatment is an option in selected patients (nondemented, <70 years old, previous good LD response). The surgical treatment of choice is currently subthalamic nucleus deep-brain stimulation. Physiotherapy, occupational therapy and speech therapy are valuable in advanced PD cases.

Designing auditory cues for Parkinson's disease gait rehabilitation

Recent works have proved that Parkinson's disease (PD) patients can be largely benefit by performing rehabilitation exercises based on audio cueing and music therapy. Specially, gait can benefit from repetitive sessions of exercises using auditory cues. Nevertheless, all the experiments are based on the use of a metronome as auditory stimuli. Within this work, Human-Computer Interaction methodologies have been used to design new cues that could benefit the long-term engagement of PD patients in these repetitive routines. The study has been also extended to commercial music and musical pieces by analyzing features and characteristics that could benefit the engagement of PD patients to rehabilitation tasks.

Gait performance is not influenced by working memory when walking at a self-selected pace

Gait performance exhibits patterns within the stride-to-stride variability that can be indexed using detrended fluctuation analysis (DFA). Previous work employing DFA has shown that gait patterns can be influenced by constraints, such as natural aging or disease, and they are informative regarding a person's functional ability. Many activities of daily living require concurrent performance in the cognitive and gait domains; specifically working memory is commonly engaged while walking, which is considered dual-tasking. It is unknown if taxing working memory while walking influences gait performance as assessed by DFA. This study used a dual-tasking paradigm to determine if performance decrements are observed in gait or working memory when performed concurrently. Healthy young participants (N = 16) performed a working memory task (automated operation span task) and a gait task (walking at a self-selected speed on a treadmill) in single- and dual-task conditions. A second dual-task condition (reading while walking) was included to control for visual attention, but also introduced a task that taxed working memory over the long term. All trials involving gait lasted at least 10 min. Performance in the working memory task was indexed using five dependent variables (absolute score, partial score, speed error, accuracy error, and math error), while gait performance was indexed by quantifying the mean, standard deviation, and DFA α of the stride interval time series. Two multivariate analyses of variance (one for gait and one for working memory) were used to examine performance in the single- and dual-task conditions. No differences were observed in any of the gait or working memory dependent variables as a function of task condition. The results suggest the locomotor system is adaptive enough to complete a working memory task without compromising gait performance when walking at a self-selected pace.

Synthesis of walking sounds for alleviating gait disturbances in Parkinson's disease

Managing gait disturbances in people with Parkinson's disease is a pressing challenge, as symptoms can contribute to injury and morbidity through an increased risk of falls. While drug-based interventions have limited efficacy in alleviating gait impairments, certain nonpharmacological methods, such as cueing, can also induce transient improvements to gait. The approach adopted here is to use computationally-generated sounds to help guide and improve walking actions. The first method described uses recordings of force data taken from the steps of a healthy adult which in turn were used to synthesize realistic gravel-footstep sounds that represented different spatio-temporal parameters of gait, such as step duration and step length. The second method described involves a novel method of sonifying, in real time, the swing phase of gait using real-time motion-capture data to control a sound synthesis engine. Both approaches explore how simple but rich auditory representations of action based events can be used by people with Parkinson's to guide and improve the quality of their walking, reducing the risk of falls and injury. Studies with Parkinson's disease patients are reported which show positive results for both techniques in reducing step length variability. Potential future directions for how these sound approaches can be used to manage gait disturbances in Parkinson's are also discussed.

Into the groove: can rhythm influence Parkinson's disease?

Previous research has noted that music can improve gait in several pathological conditions, including Parkinson's disease, Huntington's disease and stroke. Current research into auditory-motor interactions and the neural bases of musical rhythm perception has provided important insights for developing potential movement therapies. Specifically, neuroimaging studies show that rhythm perception activates structures within key motor networks, such as premotor and supplementary motor areas, basal ganglia and the cerebellum - many of which are compromised to varying degrees in Parkinson's disease. It thus seems likely that automatic engagement of motor areas during rhythm perception may be the connecting link between music and motor improvements in Parkinson's disease. This review seeks to describe the link, address core questions about its underlying mechanisms, and examine whether it can be utilized as a compensatory mechanism.

An untethered shoe with vibratory feedback for improving gait of Parkinson's patients: the PDShoe

Subjects with Parkinson's disease (PD) often have trouble with ambulation. Some research has shown that auxiliary cueing in the form of vision, audio, or vibration can improve the gait of PD patients. We have developed a new vibratory feedback shoe, known as the PDShoe, which builds on existing research. This device can modulate both frequency and amplitude of feedback for the wearer. It is untethered, and thus can be worn during daily activities. Pressure and tactor status data are transmitted wirelessly over a personal area network to a notebook computer. This computer can also control the tactor actuation and stimulation frequency. This paper describes the details of design and construction of the PDShoe. A preliminary evaluation with four Parkinson's disease subjects and two healthy subjects is included to show the usability of the device.

Effects of augmented proprioceptive cues on the parameters of gait of individuals with Parkinson's disease

Context:

Impairment of initiating sequential movements and processing of proprioception contribute to characteristic Parkinson's disease (PD) gait abnormalities. Many studies have used a single external cue or 2 different cues to correct PD gait.

Aim:

An aim of this study was to determine the influence of paired proprioceptive cues on gait parameters of individuals with PD.

Setting and Design:

Double-blind randomized controlled trial.

Materials and Methods:

Subjects were 30 PD patients who had mild to moderate impairment according to the United Parkinson's Disease Rating Scale (UPDRS). They were randomly assigned to either a routine physiotherapy program or treadmill training with vibratory stimuli applied to the feet plantar surfaces and proprioceptive neuromuscular facilitation (PNF) as well as the same physiotherapy program. All Participants received a 45-minutes session of low intensity physiotherapy program, 3 times a week, for 8 weeks. The duration of treadmill training was 5 minutes at baseline and 25 minutes at the end of treatment. Walking speed and distance were recorded from the treadmill control panel for both groups before and immediately after the end of treatment. The Qualysis ProReflex motion analysis system was used to measure cadence, stride length, hip, knee, and ankle joints’ angular excursion.

Results:

The cadence, stride length, and lower limb joints’ angular excursion showed a significant improvement in both groups (P ≤ 0.05). These improvements in spatio-temporal parameters and angular excursion were higher in the study group than in the control group (P ≤ 0.05).

Conclusion:

Potentiated proprioceptive feedback improves parkinsonian gait kinematics, the hip, knee, and ankle joints’ angular excursion.

Effects of different focus of attention rehabilitative training on gait performance in Multiple Sclerosis patients

The present investigation studied the effects of different focus of attention training on gait performance. Twelve volunteers with Multiple Sclerosis and with an average disability score (Expanded Disability Status Scale=6.5) were selected from a Medical School and took part in a three-phase intervention including baseline, internal focus, and external focus, for eight weeks. In the baseline condition, the participants walked on a treadmill without any information. In the first (internal-focus) intervention they focused on foot performance and in the second (external-focus) intervention they focused on external markers and auditory information. The results of within-group analysis of variance showed that the external intervention was significantly (p<.05) better than the other conditions for stride length, step length, step speed, and gait energy expenditure, but not for force and stride timing (p>.05). In conclusion, the second (external-focus) intervention was found to be an appropriate perceptual training method and to result in improvements in some of the gait performance parameters.

Gait disorders

This chapter deals with the neuronal mechanisms underlying impaired gait. The aim is, first, a better understanding of the underlying pathophysiology and, second, the selection of an adequate treatment. One of the first symptoms of a lesion within the central motor system perceived by patients is a movement disorder, which is most characteristic during locomotion, e.g. in patients suffering spasticity after stroke or a spinal cord injury or Parkinson disease. By the recording and analysis of electrophysiological and biomechanical signals during a movement, the significance of impaired reflex behavior or muscle tone and its contribution to the movement disorder can reliably be assessed. Adequate treatment should not be restricted to the correction of an isolated clinical sign but should be based on the mechanisms underlying the movement disorder that impairs the patient. Therapy should be directed toward functional training, which takes advantage of the plasticity of the nervous system. In the future a combination of repair and functional training will further improve the mobility of disabled patients.

Comparison of exercise strategies for motor symptom improvement in Parkinson’s disease

SUMMARY Aims: To evaluate the effectiveness of four exercise interventions on motor symptoms of Parkinson’s disease (PD). Materials and methods: This was a quasi-experimental trial with 89 participants assigned to one of four exercise programs (aquatic, aerobic, strength and sensory attention-focused exercise) or a control group. All groups were assessed by a blinded evaluator with the Unified Parkinson’s Disease Rating Scale (UPDRS III) motor section before exercises began (pre-test), immediately following exercise (post-test) and a subgroup was followed for a 6-week nonexercise washout period (washout). Results: Only sensory attention-focused exercise resulted in significant symptomatic improvement relative to nonexercising control participants. The sensory (6.7 points) and strength training (5.5 points) groups also had significant UPDRS III reductions from pre- to post-exercise. These benefits were not maintained after the washout period. Conclusion: Of the exercise modalities tested, sensory attention-focused exercise and strength training were the most effective strategies for individuals with PD. Future randomized trials are needed to confirm these results and compare other promising strategies aimed at specific pathophysiological deficits of PD.

Rehabilitation interventions in Parkinson disease

OBJECTIVE

This self-directed learning module provides an evidence-based update of exercise-based rehabilitation interventions to treat Parkinson disease (PD). It is part of the study guide on stroke and neurodegenerative disorders in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This focused review emphasizes treatment of locomotion deficits, upper limb motor control deficits, and hypokinetic dysarthria. New dopaminergic agents and deep brain stimulation are facilitating longer periods of functional stability for patients with PD. Adjunctive exercise-based treatments can therefore be applied over longer periods of time to optimize function before inevitable decline from this neurodegenerative disease. As function deteriorates in patients with PD, the role of caregivers becomes more critical, thus training caregivers is of paramount importance to help maintain a safe environment and limit caregiver anxiety and depression. The overall goal of this article is to enhance the learner's existing practice techniques used to treat PD through exercise-based intervention methods.

Falls in Parkinson's disease: evidence for altered stepping strategies on compliant surfaces

BACKGROUND

Real-world environments comprise surfaces of different textures, densities and gradients, which can threaten postural stability and increase falls risk. However, there has been limited research that has examined how walking on compliant surfaces influences gait and postural stability in older people and PD patients.

METHODS

PD patients (n = 49) and age-matched controls (n = 32) were assessed using three-dimensional motion analysis during self-paced walking on both firm and foam walkways. Falls were recorded prospectively over 12 months using daily falls calendars.

RESULTS

Walking on a foam surface influenced the temporospatial characteristics for all groups, but PD fallers adopted very different joint kinematics compared with controls. PD fallers also demonstrated reduced toe clearance and had increased mediolateral head motion (relative to walking velocity) compared with control participants.

CONCLUSIONS

Postural control deficits in PD fallers may impair their capacity to attenuate surface-related perturbations and control head motion. The risk of falling for PD patients may be increased on less stable surfaces.

Walking to the beat of different drums: practical implications for the use of acoustic rhythms in gait rehabilitation

Acoustic rhythms are frequently used in gait rehabilitation, with positive instantaneous and prolonged transfer effects on various gait characteristics. The gait modifying ability of acoustic rhythms depends on how well gait is tied to the beat, which can be assessed with measures of relative timing of auditory-motor coordination. We examined auditory-motor coordination in 20 healthy elderly individuals walking to metronome beats with pacing frequencies slower than, equal to, and faster than their preferred cadence. We found that more steps were required to adjust gait to the beat, the more the metronome rate deviated from the preferred cadence. Furthermore, participants anticipated the beat with their footfalls to various degrees, depending on the metronome rate; the faster the tempo, the smaller the phase advance or phase lead. Finally, the variability in the relative timing between footfalls and the beat was smaller for metronome rates closer to the preferred cadence, reflecting superior auditory-motor coordination. These observations have three practical implications. First, instantaneous effects of acoustic stimuli on gait characteristics may typically be underestimated given the considerable number of steps required to attune gait to the beat in combination with the usual short walkways. Second, a systematic phase lead of footfalls to the beat does not necessarily reflect a reduced ability to couple gait to the metronome. Third, the efficacy of acoustic rhythms to modify gait depends on metronome rate. Gait is coupled best to the beat for metronome rates near the preferred cadence.

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.

Falls in Parkinson's disease: kinematic evidence for impaired head and trunk control

Changes in stride characteristics and gait rhythmicity characterize gait in Parkinson's disease and are widely believed to contribute to falls in this population. However, few studies have examined gait in PD patients who fall. This study reports on the complexities of walking in PD patients who reported falling during a 12-month follow-up. Forty-nine patients clinically diagnosed with idiopathic PD and 34 controls had their gait assessed using three-dimensional motion analysis. Of the PD patients, 32 (65%) reported at least one fall during the follow-up compared with 17 (50%) controls. The results showed that PD patients had increased stride timing variability, reduced arm swing and walked with a more stooped posture than controls. Additionally, PD fallers took shorter strides, walked slower, spent more time in double-support, had poorer gait stability ratios and did not project their center of mass as far forward of their base of support when compared with controls. These stride changes were accompanied by a reduced range of angular motion for the hip and knee joints. Relative to walking velocity, PD fallers had increased mediolateral head motion compared with PD nonfallers and controls. Therefore, head motion could exceed "normal" limits, if patients increased their walking speed to match healthy individuals. This could be a limiting factor for improving gait in PD and emphasizes the importance of clinically assessing gait to facilitate the early identification of PD patients with a higher risk of falling.

Gait analysis comparing Parkinson's disease with healthy elderly subjects

There is a lack of studies comparing the kinematics data of idiopathic Parkinson's disease (IPD) patients with healthy elder (HE) subjects, and when there is such research, it is not correlated to clinical measures.

OBJECTIVE

To compare the spatio-temporal and kinematic parameters of Parkinsonian gait with the HE subjects group and measure the relation between these parameters and clinical instruments.

METHOD

Twelve patients with IPD and fifteen HE subjects were recruited and evaluated for clinical instruments and gait analysis.

RESULTS

There were statistically significant differences between HE group and the IPD group, in stride velocity, in stride length (SL), and in the hip joint kinematic data: on initial contact, on maximum extension during terminal contact and on maximum flexion during mid-swing. Regarding the clinical instruments there were significant correlated with in stride velocity and SL.

CONCLUSION

Clinical instruments used did not present proper psychometric parameters to measure the IPD patient's gait, while the 3D system characterized it better.

Walking with music is a safe and viable tool for gait training in Parkinson's disease: the effect of a 13-week feasibility study on single and dual task walking

This study explored the viability and efficacy of integrating cadence-matched, salient music into a walking intervention for patients with Parkinson's disease (PD). Twenty-two people with PD were randomised to a control (CTRL, n = 11) or experimental (MUSIC, n = 11) group. MUSIC subjects walked with an individualised music playlist three times a week for the intervention period. Playlists were designed to meet subject's musical preferences. In addition, the tempo of the music closely matched (±10–15 bpm) the subject's preferred cadence. CTRL subjects continued with their regular activities during the intervention. The effects of training accompanied by “walking songs” were evaluated using objective measures of gait score. The MUSIC group improved gait velocity, stride time, cadence, and motor symptom severity following the intervention. This is the first study to demonstrate that music listening can be safely implemented amongst PD patients during home exercise.

Mechanisms involved in treadmill walking improvements in Parkinson's disease

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.

Kinematic features of continuous hand reaching movements under simple and complex rhythmical constraints

BACKGROUND

Auditory cues are known to alter movement kinematics in healthy people as well as in people with neurological conditions (e.g., Parkinson's disease or stroke). Pacing movement to rhythmical constraints is known to change both the spatial and temporal features of movement. However, the effect of complexity of pacing on the spatial and temporal kinematic properties is still poorly understood. The current study investigated spatial and temporal aspects of movement (path and speed, respectively) and their integration while subjects followed simple isochronous or complex non-isochronous rhythmical constraints. Spatiotemporal decoupling was expected under the latter constraint.

METHODS

Ten subjects performed point-to-point hand movements towards visual targets on the surface of a hemisphere, while following continuous auditory cues of different pace and meter. The spatial and temporal properties of movement were compared to geodesic paths and unimodal bell-shaped speed profiles, respectively. Multiple two-way RM-ANOVAs (pace [1-2 Hz] x meter [duple-triple]) were performed on the different kinematic variables calculated to assess hand deviations from the model data (p< or = 0.05).

RESULTS

As expected, increasing pace resulted in straighter hand paths and smoother speed profiles. Meter, however, affected only the path (shorter and straighter under triple) without significantly changing speed. Such an effect was observed at the slow pace only.

CONCLUSIONS

Under simple rhythmic cues, an increase in pace causes spontaneous adjustments in spatial features (straighter hand paths) while preserving temporal ones (maximally-smoothed hand speeds). Complex rhythmical cues in contrast perturb spatiotemporal coupling and challenge movement control. These results may have important practical implications in motor rehabilitation.

Timing and the control of rhythmic upper-limb movements

Accurate timing of limb displacement is crucial for effective motor control. The authors examined the effects of movement velocity, duration, direction, added mass, and auditory cueing on timing, spatial, and trajectory variability of single- and multijoint rhythmic movements. During single-joint movements, increased velocity decreased timing and spatial variability, whereas increased movement duration increased timing variability but decreased spatial variability. For multijoint movements, regardless of condition, increasing velocity decreased joint timing, spatial, and trajectory variability, but all hand variabilities were unaffected by velocity, duration, load, or direction. Timing, spatial, and trajectory variability was greater at the shoulder compared with the elbow and minimal at the hand, supporting the notion that reaching movements are planned in hand space as opposed to joint space.

Frequency-velocity mismatch: a fundamental abnormality in parkinsonian gait

Gait dysfunction and falling are major sources of disability for patients with advanced Parkinson's disease (PD). It is presently thought that the fundamental defect is an inability to generate normal stride length. Our data suggest, however, that the basic problem in PD gait is an impaired ability to match step frequency to walking velocity. In this study, foot movements of PD and normal subjects were monitored with an OPTOTRAK motion-detection system while they walked on a treadmill at different velocities. PD subjects were also paced with auditory stimuli at different frequencies. PD gait was characterized by step frequencies that were faster and stride lengths that were shorter than those of normal controls. At low walking velocities, PD stepping had a reduced or absent terminal toe lift, which truncated swing phases, producing shortened steps. Auditory pacing was not able to normalize step frequency at these lower velocities. Peak forward toe velocities increased with walking velocity and PD subjects could initiate appropriate foot dynamics during initial phases of the swing. They could not control the foot appropriately in terminal phases, however. Increased treadmill velocity, which matched the natural PD step frequency, generated a second toe lift, normalizing step size. Levodopa increased the bandwidth of step frequencies, but was not as effective as increases in walking velocity in normalizing gait. We postulate that the inability to control step frequency and adjust swing phase dynamics to slower walking velocities are major causes for the gait impairment in PD.

Potential influences of complementary therapy on motor and non-motor complications in Parkinson's disease

Nearly two-thirds of patients with Parkinson's disease (PD) use vitamins or nutritional supplements, and many more may use other complementary therapies, yet <50% of patients have discussed the use of these complementary therapies with a healthcare professional. Physicians should be aware of the complementary therapies their patients with PD are using, and the possible effects of these therapies on motor and non-motor symptoms. Complementary therapies, such as altered diet, dietary supplements, vitamin therapy, herbal supplements, caffeine, nicotine, exercise, physical therapy, massage therapy, melatonin, bright-light therapy and acupuncture, may all influence the symptoms of PD and/or the effectiveness of dopaminergic therapy. Preliminary evidence suggests complementary therapy also may influence non-motor symptoms of PD, such as respiratory disorders, gastrointestinal disorders, mood disorders, sleep and orthostatic hypotension. Whenever possible, clinicians should ensure that complementary therapy is used appropriately in PD patients without reducing the benefits of dopaminergic therapy.

Rehabilitation treatment of gait in patients with Parkinson's disease with freezing: a comparison between two physical therapy protocols using visual and auditory cues with or without treadmill training

Freezing is a disabling symptom in patients with Parkinson's disease. We investigated the effectiveness of a new rehabilitation strategy based on treadmill training associated with auditory and visual cues. Forty Parkinsonian patients with freezing were randomly assigned to two groups: Group 1 underwent a rehabilitation program based on treadmill training associated with auditory and visual cues, while Group 2 followed a rehabilitation protocol using cues and not associated with treadmill. Functional evaluation was based on the Unified Parkinson's Disease Rating Scale Motor Section (UPDRS III), Freezing of Gait Questionnaire (FOGQ), 6-minute walking test (6MWT), gait speed, and stride cycle. Patients in both the groups had significant improvements in all variables considered by the end of the rehabilitation program (all P = 0.0001). Patients treated with the protocol including treadmill, had more improvement than patients in Group 2 in most functional indicators (P = 0.007, P = 0.0004, P = 0.0126, and P = 0.0263 for FOGQ, 6MWT, gait speed, stride cycle, respectively). The most striking result was obtained for 6MWT, with a mean increase of 130 m in Group 1 compared with 57 m in Group 2. Our results suggest that treadmill training associated with auditory and visual cues might give better results than more conventional treatments. Treadmill training probably acts as a supplementary external cue.

Walking stability using harmonic ratios in Parkinson's disease

Kinematic changes in Parkinson's disease (PD) gait are well documented; however, upper body dynamics are less understood. Harmonic ratios (HRs) measure the rhythm of trunk accelerations and can be examined in the vertical, anterior-posterior, and mediolateral planes, providing an indication of global walking stability (lower HR indicates poorer stability). We examined differences in HRs between persons with PD and healthy older adults and relationships between HRs and stride parameters. Eleven people with PD and 11 older adults walked over ground at their preferred pace. A triaxial accelerometer measured trunk accelerations. HRs and spatiotemporal parameters were calculated and standardized to remove the influence of gait velocity. The PD group exhibited lower HRs in all three planes, with the most pronounced differences in the mediolateral and anterior-posterior planes. Greater stride time variability was most closely associated with a lower anterior-posterior HR in PD and the presence of disease with the mediolateral HR. By demonstrating decreased walking stability in medial-lateral and anterior-posterior planes, we conclude that HRs offer unique information beyond that of typical stride parameters, and stride time variability is most closely associated with these direct measures of global walking stability.

Analysis of spatial temporal plantar pressure pattern during gait in Parkinson's disease

Spatial temporal plantar pressure patterns measured with sheet-shaped pressure sensor were investigated to extract features of gait in Parkinson's disease. Both six subjects of Parkinson's disease (PD) and elderly fourteen normal control subjects were asked to execute usual walking on the pressure sensor sheets. Candidate features were step length, step time, gait velocity and transition of center of pressure to foot axis direction. The step length and gait velocity were smaller in PD subjects than those in normal subjects. Time of step cycle in three PD subjects were longer than that in normal subjects while the times of other PD subjects were similar to those of control subjects. The length from heel contact to toe off within one footprint was small in the subjects with short step length. Such possibility was indicated that Parkinson's disease in gait could be separated from normal subjects by these features.