Metronome in Parkinson's disease

The neural correlates of gait improvement by rhythmic sound stimulation in adults with Parkinson's disease - A functional magnetic resonance imaging study

INTRODUCTION

Adults with Parkinson's disease (PD) experience gait disturbances that can sometimes be improved with rhythmic auditory stimulation (RAS); however, the underlying physiological mechanism for this improvement is not well understood. We investigated brain activation patterns in adults with PD and healthy controls (HC) using functional magnetic resonance imaging (fMRI) while participants imagined gait with or without RAS.

METHODS

Twenty-seven adults with PD who could walk independently and walked more smoothly with rhythmic auditory cueing than without it, and 25 age-matched HC participated in this study. Participants imagined gait in the presence of RAS or white noise (WN) during fMRI.

RESULTS

In the PD group, gait imagery with RAS activated cortical motor areas, including supplementary motor areas and the cerebellum, while gait imagery with WN additionally recruited the left parietal operculum. In HC, the induced activation was limited to cortical motor areas and the cerebellum for both the RAS and WN conditions. Within- and between-group analyses demonstrated that RAS reduced the activity of the left parietal operculum in the PD group but not in the HC group (condition-by-group interaction by repeated measures analysis of variance, p < 0.05).

CONCLUSION

During gait imagery in adults with PD, the left parietal operculum was less activated by RAS than by WN, while no change was observed in HC, suggesting that rhythmic auditory stimulation may support the sensory-motor networks involved in gait, thus alleviating the overload of the parietal operculum and compensating for its dysfunction in these patients.

Perception of Time in Music in Patients with Parkinson's Disease-The Processing of Musical Syntax Compensates for Rhythmic Deficits

Objective: Perception of time as well as rhythm in musical structures rely on complex brain mechanisms and require an extended network of multiple neural sources. They are therefore sensitive to impairment. Several psychophysical studies have shown that patients with Parkinson's disease (PD) have deficits in perceiving time and rhythms due to a malfunction of the basal ganglia (BG) network.

Method: In this study we investigated the time perception of PD patients during music perception by assessing their just noticeable difference (JND) in the time perception of a complex musical Gestalt. We applied a temporal discrimination task using a short melody with a clear beat-based rhythm. Among the subjects, 26 patients under L-Dopa administration and 21 age-matched controls had to detect an artificially delayed time interval in the range between 80 and 300 ms in the middle of the musical period. We analyzed the data by (a) calculating the detection threshold directly, (b) by extrapolating the JNDs, (c) relating it to musical expertise.

Results: Patients differed from controls in the detection of time-intervals between 220 and 300 ms (^*p = 0.0200, n = 47). Furthermore, this deficit depended on the severity of the disease (^*p = 0.0452; n = 47). Surprisingly, PD patients did not show any deficit of their JND compared to healthy controls, although the results showed a trend (^*p = 0.0565, n = 40). Furthermore, no significant difference of the JND was found according to the severity of the disease. Additionally, musically trained persons seemed to have lower thresholds in detecting deviations in time and syntactic structures of music (^*p = 0.0343, n = 39).

Conclusion: As an explanation of these results, we would like to propose the hypothesis of a time-syntax-congruency in music perception suggesting that processing of time and rhythm is a Gestalt process and that cortical areas involved in processing of musical syntax may compensate for impaired BG circuits that are responsible for time processing and rhythm perception. This mechanism may emerge more strongly as the deficits in time processing and rhythm perception progress. Furthermore, we presume that top-down-bottom-up-processes interfere additionally and interact in this context of compensation.

Predictive timing functions of cortical beta oscillations are impaired in Parkinson's disease and influenced by L-DOPA and deep brain stimulation of the subthalamic nucleus

Cortex-basal ganglia circuits participate in motor timing and temporal perception, and are important for the dynamic configuration of sensorimotor networks in response to exogenous demands. In Parkinson's disease (PD) patients, rhythmic auditory stimulation (RAS) induces motor performance benefits. Hitherto, little is known concerning contributions of the basal ganglia to sensory facilitation and cortical responses to RAS in PD. Therefore, we conducted an EEG study in 12 PD patients before and after surgery for subthalamic nucleus deep brain stimulation (STN-DBS) and in 12 age-matched controls. Here we investigated the effects of levodopa and STN-DBS on resting-state EEG and on the cortical-response profile to slow and fast RAS in a passive-listening paradigm focusing on beta-band oscillations, which are important for auditory–motor coupling. The beta-modulation profile to RAS in healthy participants was characterized by local peaks preceding and following auditory stimuli. In PD patients RAS failed to induce pre-stimulus beta increases. The absence of pre-stimulus beta-band modulation may contribute to impaired rhythm perception in PD. Moreover, post-stimulus beta-band responses were highly abnormal during fast RAS in PD patients. Treatment with levodopa and STN-DBS reinstated a post-stimulus beta-modulation profile similar to controls, while STN-DBS reduced beta-band power in the resting-state. The treatment-sensitivity of beta oscillations suggests that STN-DBS may specifically improve timekeeping functions of cortical beta oscillations during fast auditory pacing.

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High density EEG investigation in patients with PD before and after STN-DBS surgery

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Resting state EEG: altered spectral composition following STN-DBS

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Rhythmic auditory stimulation (RAS): absence of pre-stimulus beta activity in PD

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Fast RAS: normalization of beta (13–30 Hz) activities by L-DOPA and STN-DBS

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Altered beta modulation profile may contribute to timekeeping deficits in PD.

The effect of visual cues on the number and duration of freezing episodes in Parkinson's patients

Freezing of gait is a phenomenon common in Parkinson's patients and significantly affects quality of life. Sensory cues have been known to improve walking performance and reduce freezing of gait. Visual cues are reported to be particularly effective for this purpose. So far, sensory cues have generally been provided continuously, even when currently not needed. However, a recent approach suggests the provision of cues just in the case that freezing actually occurs. The arguments in favor of this "on-demand" cueing are reduced intrusiveness and reduced habituation to cues. Here, we analyzed the effect of visual cues on the number and duration of freezing episodes when activated either just "on-demand" or continuously and compare it to the baseline condition where no cue is provided. For this purpose, 7 Parkinson's patients regularly suffering from freezing of gait repeatedly walked a pre-defined course and their reaction to parallel laser lines projected in front of them on the floor was analyzed. The results show that, in comparison to the baseline condition, the mean duration of freezing was reduced by 51% in continuous cueing and by 69% in "on-demand" cueing. Concerning the number of freezing episodes, 43% fewer episodes were observed for continuous cueing and 9% less episodes for "on-demand" cueing.

Metronome rate and walking foot contact time in young adults

It is assumed that when people walk guided by an audible constant rate, they match foot contact to the external pace. The purpose of this preliminary study was to test that assumption by examining the temporal relationship between audible signals generated by a metronome and foot contact time during gait. Ten healthy young women were tested in walking repetitions guided by metronome rates of 60, 110, and 150 beats/min. Metronome beats and foot contact times were collected in real time. The findings indicated that foot contact was not fully synchronized with the auditory signals; the shortest time interval between the metronome beat and foot contact time was at the prescribed rate of 60 beats/min., while the longest interval was at the rate of 150 beats/min. The correlation between left and right foot contact times was highest with the slowest rate and lowest with the fastest rate.

Effect of rhythmic auditory stimulation on gait in Parkinsonian patients with and without freezing of gait

Freezing of gait (FOG) in Parkinson's disease (PD) rises in prevalence when the effect of medications decays. It is known that auditory rhythmic stimulation improves gait in patients without FOG (PD-FOG), but its putative effect on patients with FOG (PD+FOG) at the end of dose has not been evaluated yet. This work evaluates the effect of auditory rhythmic stimulation on PD+FOG at the end of dose. 10 PD+FOG and 9 PD-FOG patients both at the end of dose periods, and 10 healthy controls were asked to perform several walking tasks. Tasks were performed in the presence and absence of auditory sensory stimulation. All PD+FOG suffered FOG during the task. The presence of auditory rhythmic stimulation (10% above preferred walking cadence) led PD+FOG to significantly reduce FOG. Velocity and cadence were increased, and turn time reduced in all groups. We conclude that auditory stimulation at the frequency proposed may be useful to avoid freezing episodes in PD+FOG.

An evaluation of self-administration of auditory cueing to improve gait in people with Parkinson's disease

OBJECTIVE

To evaluate a self-administration of auditory cueing on gait difficulties in people with Parkinson's disease over a one-week period.

DESIGN

Single group pre and post test.

SETTING

Research lab, community.

PARTICIPANTS

Twenty-one individuals with Parkinson's disease.

INTERVENTIONS

Self-application of an auditory pacer set at a rate 25% faster than preferred cadence.

MAIN OUTCOME MEASURES

Self-selected gait speed, cadence, stride length, and double support time with and without the pacer at the initial visit and after one week of pacer use.

RESULTS

During the initial visit, the auditory pacer improved gait speed (79.57 (18.13) cm/s vs. 94.02 (22.61) cm/s, P<0.0005), cadence (102.88 (11.34) step/min vs. 109.22 (10.23) steps/min, P=0.036) and stride length (94.33 (21.31) cm vs. 103.5 (22.65) cm, P =0.012). After one week, preferred gait speed was faster than the initial preferred speed (79.57 (18.13) vs. 95.20 (22.23) cm/s, P<0.0005). Stride length was significantly increased (94.33 (21.31) vs. 107.67 (20.01) cm, P =0.001). Double support time was decreased from 21.73 (5.23) to 18.94 (3.59)% gait cycle, P =0.016.

CONCLUSION

Gait performance in people with Parkinson's disease improved significantly after walking with the auditory pacer for one week.

Evaluation of a new device to prevent falls in persons with Parkinson's disease

PURPOSE

To compare walking characteristics of individuals with Parkinson's disease (PD) using a new walking aid, the WalkAbout, with usual walking.

METHOD

Fifteen subjects with PD were recruited. Subjects walked in their usual fashion and then walked again in the WalkAbout. Gait parameters, 5-min walk, and oxygen consumption were recorded.

RESULTS

Stride lengths were shorter when using the WalkAbout. On an average, the distance walked in 5 min and the oxygen uptake was not different when walking with the WalkAbout compared with the usual walk. Eight subjects (responders) walked further with the WalkAbout compared to their usual walk (164.90 +/- 55.72 m vs. 140.82 +/- 55.94 m). Seven subjects (non-responders) walked a shorter distance while using the WalkAbout compared to their usual walk (241.79 +/- 73.06 m vs. 281.24 +/- 82.83 m). Compared to non-responders, responders were older, had more severe disability, and were more likely to use an assistive device for walking. Responders walked more slowly, had a shorter stride length, and walked shorter distances in 5 min than non-responders.

CONCLUSION

The WalkAbout may help persons with PD who have more severe disability to walk farther. These data could be beneficial in selecting a helpful walking aid for persons with PD.

Enhancement of reaching performance via self-speech in people with Parkinson's disease

OBJECTIVE

To evaluate the effects of self-speech as an internal cue on reaching performance in people with Parkinson's disease.

SUBJECTS

Eight people with Parkinson's disease were voluntarily recruited from the upstate New York community.

DESIGN AND SETTING

This study was a repeated measure analysis of reaching performance under four randomized counterbalanced vocalization (speech) conditions that include a no vocalization control condition. The study was conducted in a university-based motion analysis laboratory. Participants performed a simple sequential daily reaching performance of reaching for a bottle, grasping and placing it on a simulated cabinet. Under counterbalanced randomized conditions, before each performance, participants either self-vocalized the word 'yaah' (self-cue), listened to the word 'yaah' vocalized by the experimenter (external cue), imagined vocalizing the word 'yaah', or just simply performed the task without any vocalization (control - no vocalization).

MAIN MEASURES

The following dependent kinematic measures were extracted from the movement: total movement time, total movement unit, peak velocities and durations of reaching and placing segments.

RESULTS

People with Parkinson's disease took significantly shorter time under self-vocalization conditions (2390.00 (326.63) ms) compared with the other three conditions including control - no vocalization conditions (no_voc, 3015.66 (340.83) ms; ext_voc, 2853.12 (376.44) ms; imaginary-voc, 3000.37 (320.54) ms). Under self-vocalization conditions the movements were also significantly smoother as evidenced by significantly lower numbers of movement units (3.43 (0.41)) compared with the other three conditions (no_voc, 4.47 (0.57); ext_voc, 4.16 (0.51); imaginary-voc, 4.16 (0.55)).

CONCLUSIONS

Self-vocalization of a positive reinforcing word enabled people with Parkinson's disease to perform a daily upper extremity task faster and more smoothly.

Effects of visual and auditory cues on gait initiation in people with Parkinson's disease

OBJECTIVE

To evaluate the effects of auditory and visual cues on gait initiation in people with Parkinson's disease.

SUBJECTS

Fourteen subjects with Parkinson's disease were recruited from community support groups, seven of whom reported having experienced freezing when walking.

DESIGN AND SETTING

This study was a repeated measures analysis of gait initiation performance during a single visit to a university-based motion laboratory. Following baseline trials, auditory and visual cue conditions were presented in random order. The auditory cues were rhythmic sounds with an interval matching the subject's average step time. The visual cues were high-contrast transverse lines on the floor adjusted for the subject's first step length and overall height.

MAIN MEASURES

Kinematic recordings enabled calculation of the timing and length of steps as well as overall velocity. The timing and magnitude of weight shift and push-off force were obtained from a force platform.

RESULTS

The magnitudes of first and second step lengths, of push-off force and of overall gait velocity were significantly greater in the visual cue condition than in the baseline condition, whereas there was no significant effect of auditory cue on these measures. Neither cue had any significant effect on the timing of key events in gait initiation.

CONCLUSIONS

Transverse line visual cues enable people with Parkinson's disease to begin walking with longer steps, greater push-off force and higher velocity. Auditory cues that others have shown to improve aspects of gait in people with Parkinson's disease do not appear to have any systematic effect on the first two steps of gait initiation.

Wheeled and standard walkers in Parkinson's disease patients with gait freezing

OBJECTIVES

Compare the efficacy of two walking assistance devices (wheeled walker and standard walker) to unassisted walking for patients with PD and gait freezing.

BACKGROUND

Although numerous walking devices are used clinically, their relative effects on freezing and walking speed have never been systematically tested.

METHODS

Nineteen PD patients (14 non-demented) walked under three conditions in randomized order: unassisted walking, standard walker, and wheeled walker. Patients walked up to three times in each condition through a standard course that included rising from a chair, walking through a doorway, straightway walking, pivoting, and return. Total walking time, freezing time and number of freezes were compared for the three conditions using mixed models (walking time) and Friedman's test (freezing). The wheeled walker was further studied by comparing the effect of an attached laser that projected a bar of light on the floor as a visual walking cue.

RESULTS

Use of either type of device significantly slowed walking compared to unassisted walking. Neither walker reduced any index of freezing, nor the laser attachment offered any advantage to the wheeled walker. The standard walker increased freezing, and the wheeled walker had no effect on freezing. Among the non-demented subjects (n=14), the same patterns occurred, although the walking speed was less impaired by the wheeled walker than the standard walker in this group.

CONCLUSIONS

Though walkers may stabilize patients and increase confidence, PD patients walk more slowly when using them, without reducing freezing. Because the wheeled walker was intermediate for walking time and does not aggravate freezing, if walkers are used for these subjects, this type of walker should be favored.

The power of cueing to circumvent dopamine deficits: a review of physical therapy treatment of gait disturbances in Parkinson's disease

Gait disturbances are among the primary symptoms of Parkinson's disease (PD) and contribute significantly to a patient's loss of function and independence. Standard treatment includes antiparkinsonian drugs, primarily levodopa. In addition to the standard drug regime, physical therapy is often prescribed to help manage the disease. In recent years, there have been promising reports of physical therapy programs combined with various types of sensory cueing for PD. In this brief review of the literature, we summarize the evidence regarding the clinical efficacy of different physical therapy programs for PD, specifically with respect to improving gait. We also discuss the potential therapeutic mechanisms of sensory cueing and review the studies that have used cueing in the treatment of gait in PD. This review of the literature shows two key findings: (1) despite its relatively long history, the evidence supporting the efficacy of conventional physical therapy for treatment of gait in PD is not strong; and (2) although further investigation is needed, sensory cueing appears to be a powerful means of improving gait in PD.

A walking stick for a pure akinesia patient

We describe a 63-year-old female patient with pure akinesia whose gait was facilitated by a handmade converted walking stick. A posterior ventral pallidotomy had been performed, but it did not alleviate symptoms. Her husband made a walking stick with a wire loop at the bottom, perpendicular to the walking direction. When the patient stepped over the loop, the frozen gait was improved. This converted walking stick is easily made and inexpensive. Although the walking stick did not improve the patient's gait radically, use of the converted walking stick effectively improved the patient's daily life because successful treatment of pure akinesia cannot be established.

Therapeutic value of exercise training in Parkinson's disease

PURPOSE

The objective of this study was to investigate the influence of an intensive exercise training on motor disability, mood, and subjective well-being in parkinsonian patients.

METHODS

The study was designed as an open long-term pilot trial over 20 wk. Sixteen slightly to moderately affected idiopathic parkinsonian patients (PD) were included. An intensive standardized exercise training was performed twice weekly over 14 wk in all patients. Evaluations were performed before the start of the study (exam. 1), after 7 wk (exam 2), 14 wk (exam 3), and 20 wk (exam 4/long-term effect). The test battery included: 1) basic motor test (BMT) [test for muscle strength, flexibility, and coordination]; 2) Unified Parkinson's Disease Rating Scale (UPDRS) and Columbia University Rating Scale (CURS) for PD-specific motor disability; and 3) registration of psychometric data by Mini Mental State (MMS) for dementia and the Adjective Mood Questionnaire of Zeersen (AMQZ) and Sickness Impact Profile (SIP) for subjective well-being.

RESULTS

UPDRS sigma score (P < 0.0001), CURS sigma score (P < 0.0001) and BMT 2 score (P < 0.0001) improved significantly by exercise training. Six weeks after termination of the training program, the majority of the patients had lost only minor components of their regained motor skills. There was no significant change in cognitive function during the study. The results of open interviews referring to subjective well-being were confirmed by the AMQZ and SIP. As an unexpected side effect, dyskinesias seemed to be better controlled.

CONCLUSION

Motor disability as well as mood and subjective well-being can be clearly improved by intensive sports activities in early to medium stage PD patients. A sustained ongoing benefit outlasting the active training period for at least 6 wk can be achieved but the exact duration of this benefit is open.

Effect of interstimulus interval on visual P300 in Parkinson's disease

OBJECTIVE

Visual event related potentials (ERPs) were studied during an oddball paradigm, to testify whether cognitive slowing in Parkinson's disease exists and to investigate whether cognitive information processing can be influenced by different interstimulus intervals (ISIs) of an oddball task in patients with Parkinson's disease and normal subjects.

METHODS

ERPs and reaction time were measured in 38 non-demented patients with Parkinson's disease and 24 healthy elderly subjects. A visual oddball paradigm was employed to evoke ERPs, at three different interstimulus (ISI) intervals: ISI(S), 1600 ms; ISI(M), 3100 ms; and ISI(L), 5100 ms. The effect of ISIs on ERPs and reaction time was investigated.

RESULTS

Compared with the normal subjects, P300 latency at Cz and Pz was significantly delayed after rare target stimuli in patients with Parkinson's disease only at ISI(L). Reaction time was prolonged in patients at all the three ISIs, compared with the normal controls. There was also significantly delayed N200 and reduced P300 amplitude at Cz and/or Pz to rare non-target stimuli in patients at the three ISIs, compared with the normal controls. During rare target visual stimulation, P300 latency and reaction time in the patients with Parkinson's disease and reaction time in the normal subjects were gradually prolonged as the ISI increased.

CONCLUSION

Prolonged N200 latency to rare non-target stimuli might indicate that automatic cognitive processing was slowed in Parkinson's disease. Cognitive processing reflected by P300 latency to rare target stimuli was influenced by longer ISI in patients with Parkinson's disease.