The effects of auditory cues and weighted pens on handwriting in individuals with Parkinson's disease.

BACKGROUND: Micrographia, or small handwriting, is a common symptom of Parkinson's disease (PD). Weighted pens have previously been recommended to improve handwriting, but there is limited research supporting their effectiveness. Additionally, previous research has demonstrated that music as an auditory cue can reduce variability in fine motor movements, but its effect on handwriting in people with PD remains unknown. PURPOSE: This study explored potential handwriting interventions for people with PD by evaluating the effectiveness of weighted pens and auditory cues on handwriting. STUDY DESIGN: This was a pilot cohort study. METHODS: Eight older adults with PD used a standard pen and a weighted pen to write continuous cursive "l"s on 1.5-cm-lined paper for a total of 10 seconds while listening to auditory cues in 4 conditions: control (silence), metronome, activating music, and relaxing music. Kinematic data were measured with sensors attached to the tip of each pen, and muscle activity was measured with electromyography sensors adhered to the extensor digitorum communis and first dorsal interosseous. RESULTS: When writing with the standard pen, peak-to-peak time was reduced in the metronome (control = 0.807 ± 0.121 seconds, metronome = 0.701 ± 0.100 seconds, p = 0.024) and activating (control = 0.807 ± 0.121 seconds, activating = 0.691 ± 0.113 seconds, p = 0.009) conditions compared to the control condition. Furthermore, the weighted pen increased the variability of distance between letter peaks (standard = 0.187 ± 0.010, weighted = 0.482 ± 0.065, p = 0.033) and the variability of time needed to complete each letter (standard = 0.176 ± 0.010, weighted = 0.187 ± 0.016, p = 0.042) compared to the standard pen. Finally, area under the curve of the extensor digitorum communis was reduced in the metronome (metronome = 66.03 ± 25.74 mV, control = 88.98 ± 30.40 mV, p = 0.034) and activating music (activating = 66.49 ± 26.02 mV, control = 88.98 ± 30.40 mV, p = 0.012) conditions compared to control when writing with the standard pen. CONCLUSIONS: These results suggest that weighted pens may not improve handwriting in novice users, but auditory cues appear beneficial. This can inform future directions in the research and clinical application of handwriting interventions for persons with PD.

Comparison of auditory cueing in toe tapping and gait in persons with Parkinson's disease.

Introduction: Much research has examined the relationship between bradykinesia and gait impairment in persons with Parkinson's disease (PD). Specifically, impairments in repetitive movements of the upper extremity have been associated with freezing of gait. Studies examining lower extremity repetitive movements are limited. Moreover, the use of external cueing has been a treatment strategy for both bradykinesia and gait, but information on how cues should be used is lacking. The purpose of this study was to compare the effects of auditory cueing on one side versus both sides for bilateral repetitive toe tapping and gait, and to determine if there was a relationship between toe tapping and gait. We hypothesize that there will be no difference between the cueing conditions, but that there will be a significant association between repetitive toe tapping performance and gait performance. Methods: Twenty-seven persons with PD completed a toe tapping task in which the more affected side was cued at 70 beats per minute (BPM), the less affected side was cued at 70 BPM, and both sides were cued at 140 BPM. The same cueing conditions were completed for the gait task. Inter movement interval and amplitude data was collected and analyzed for the toe tapping task. Stance time, swing time, step length, and step width were collected and analyzed for the gait task. Results: Results revealed a significant difference in movement performance between the single side cueing conditions and both sides cued condition for inter movement interval (toe tapping), stance time (gait), step length (gait), and step width (gait). Moreover, results revealed a significant association between inter movement interval and stance time and step length. Discussion: These results would suggest that cueing both sides is better than only one side and that there is a relationship between toe tapping and gait performance when both sides are cued in persons with PD. This study adds to the literature exploring possible shared mechanisms between bradykinesia and gait in persons with PD.

Differences in motor inhibition in young and older musicians and non-musicians at rest.

Introduction: Older adults experience a decline in motor inhibition. These declines have been implicated in instrumental activities of daily living. However, studies have revealed that older musicians have behavioral and neurophysiological enhancements in various motor domains compared to non-musicians. This suggests that music training may delay the decline in motor inhibition with aging. Nevertheless, motor inhibition has not been studied in young or older musicians and non-musicians. Thus, the present study aimed to investigate the neurophysiological differences in motor inhibition in aging musicians and non-musicians. Methods: A total of 19 healthy young adult musicians, 16 healthy young non-musicians, 13 healthy older adult musicians, and 16 healthy older adult non-musicians were recruited for the study. Transcranial magnetic stimulation single-pulse (SP) and short interval cortical inhibition (SICI) were performed at rest and then converted into inhibition percentage. Results: We did not observe significant differences between young and older musicians and non-musicians in resting SP MEP. Older adults had lower resting SICI MEP than young adults. Older adults (36%) had a greater percentage of inhibition than young adults (16%). However, when controlling for background EMG activity, musicians had a lower inhibition percentage than non-musicians. Discussion: The results revealed that, despite the greater use of spinal mechanisms, decreased SICI, and increased inhibition percentage in older adults, motor inhibitory circuitry remains intact and functional in both young and older musicians and non-musicians. Future studies will reveal whether there are differences in motor inhibition during movement in musicians across a person's lifespan.

Finger tapping to different styles of music and changes in cortical oscillations.

Music has been a therapeutic strategy proposed to improve impaired movement performance, but there remains a lack of understanding of how music impacts motor cortical activity. Thus, the purpose of this study is to use a time-frequency analysis (i.e., wavelet) of electroencephalographic (EEG) data to determine differences in motor and auditory cortical activity when moving to music at two different rates. Twenty healthy young adults tapped their index finger while electroencephalography was collected. There were three conditions (tapping in time with a tone and with two contrasting music styles), and each condition was repeated at two different rates (70 and 140 beats per minute). A time-frequency Morlet wavelet analysis was completed for electrodes of interest over the sensorimotor areas (FC3, FC4, FCz, C3, C4, Cz) and the primary auditory areas (T7, T8). Cluster-based permutation testing was applied to the electrodes of interest for all conditions. Results showed few differences between cortical oscillations when moving to music versus a tone. However, the two music conditions elicited a variety of distinct responses, particularly at the slower movement rate. These results suggest that music style and movement rate should be considered when designing therapeutic applications that include music to target motor performance.

The Effects of Group Therapeutic Singing on Cortisol and Motor Symptoms in Persons With Parkinson's Disease.

The inclusion of music into the treatment plan for persons with Parkinson's disease (PD) may be a viable strategy to target multiple motor symptoms. However, potential mechanisms to explain why music has an impact on multiple motor symptoms in persons with PD remain understudied. The purpose of this study was to examine the acute effects of 1 h of group therapeutic singing (GTS) on physiological measures of stress and clinical motor symptoms in persons with PD. We posit that improvement in motor symptoms after GTS may be related to stress reduction. Seventeen participants with PD completed 1 h of GTS and eight participants completed 1 h of a quiet reading (control session). Cortisol was collected via passive drool immediately before and after the singing and control session. The Unified Parkinson's Disease Rating Scale (UPDRS) Part-III (motor examination) was also video-recorded immediately before and after the singing and control session and scored by two raters masked to time and condition. Secondary outcome measures for quality of life, depression, and mood were collected. Results revealed no significant change in cortisol or motor UPDRS scores, as well as no significant relationship between cortisol and motor UPDRS scores. There was a trend for the singing group to report feeling less sad compared to the control group after the 1-h session (effect size = 0.86), and heart rate increased in the singing group while heart rate decreased in the control group after the 1-h session. These results suggest that an acute session of GTS is not unduly stressful and promotes the use of GTS for persons with PD. Multiple mechanisms may underlie the benefits of GTS for persons with PD. Further exploring potential mechanisms by which singing improves motor symptoms in persons with PD will provide greater insight on the therapeutic use of music for persons with PD.

Determinants of exercise behaviour in persons with Parkinson's disease.

BACKGROUND: Exercise shows promise for improving physical and cognitive functioning, quality of life, and mood in individuals with Parkinson's disease (PD). Structured interviews have suggested potential factors influencing participation in exercise in this population, but no studies have examined if they predict exercise behaviour. METHODS: Thirty persons with PD completed the International Physical Activity Questionnaire and a semi-structured interview. Time spent exercising was calculated by summing responses for recreation, sport, and leisure-time physical activity. Predictors of exercise were assessed via interview. In addition, participants were asked about what types of exercise they engaged in and what types of exercise they would be interested in trying. Regression analyses were used to identify the factors that predicted time spent exercising, as well as determining factors in low vs. high exercisers (≥150 min per week). RESULTS: Positive predictors of exercise were being male (ß= -0.52, p = 0.01; χ2 = 4.84, p = 0.03), married (ß = 0.32, p = 0.03; χ2 = 5.60, p = 0.02), and enjoyment of exercise (ß = 0.36, p = 0.02). Fear of falling (ß = -0.41, p = 0.01; χ2 = 4.29, p = 0.04), negative perception of health (ß = -0.41, p = 0.02), perception of PD symptoms (χ2 = 12.45, p < 0.001), bad weather (χ2 = 5.06, p = 0.02), and lack of an exercise partner (χ2 = 13.39, p < 0.001) were negative predictors of exercise. CONCLUSIONS: Results from this study suggest that exercise programmes should work to make activities enjoyable, safe, and adaptable to the abilities of the individual. Programmes should also include social engagement.Implications for rehabilitationParkinson's exercise programmes should be enjoyable.Parkinson's exercise programmes should include both social engagement and social support.Parkinson's exercise programmes should be safe and adaptable to the abilities of the participants.Parkinson's exercise programmes should aim to improve balance and reduce fear of falling.Individual exercise programmes can also be successful, many people with PD exercise alone with the most common form being walking.

Effects of Levodopa on Impairments to High-Level Vision in Parkinson's Disease.

Studies have reported that Parkinson's disease (PD) is associated with impairments on cognitive visual tasks. However, the effects of dopamine on cognitive vision remain equivocal. The purpose of this study was to examine performance on cognitive vision tasks in persons with PD and the effects of levodopa on these tasks. Fourteen individuals with PD and 14 age- and sex-matched healthy older adults completed the study. Participants with PD completed the visual tasks following a 12-h withdrawal of dopaminergic medication and again 1 h after taking 1.5 times their normal dose of levodopa. Healthy older adults completed the visual tasks twice using the same session format. Five complex visual tasks were completed, including line discrimination, object discrimination, facial discrimination, visual working memory, and object rotation. The Unified Parkinson's Disease Rating Scale was also collected off and on medication. Participants with PD performed significantly worse than the healthy older adults across all five visual tasks. There were no significant differences in performance between the off and on medication state in persons with PD. This finding indicates either that dopamine deficiency may not be responsible for cognitive visual impairments in PD or that cognitive visual impairments in PD might simply be the result of deficits in more basic visual processing.

Music Form but Not Music Experience Modulates Motor Cortical Activity in Response to Novel Music.

External cues, such as music, improve movement performance in persons with Parkinson's disease. However, research examining the motor cortical mechanisms by which this occurs is lacking. Research using electroencephalography in healthy young adults has revealed that moving to music can modulate motor cortical activity. Moreover, motor cortical activity is further influenced by music experience. It remains unknown whether these effects extend to corticomotor excitability. Therefore, the primary aim of this study was to determine the effects of novel music on corticomotor excitability using transcranial magnetic stimulation (TMS) in a pilot study of healthy young adults. A secondary aim of this study was to determine the influence of music experience on corticomotor excitability. We hypothesized that corticomotor excitability will change during music conditions, and that it will differ in those with formal music training. Motor evoked potentials (MEPs) were recorded from the first dorsal interosseous using single-pulse TMS in three conditions: (1) No Music, (2) Music Condition I, and (3) Music Condition II. Both pieces were set to novel MIDI piano instrumentation and part-writing conventions typical of early nineteenth-century Western classical practices. Results revealed Music Condition II (i.e., more relaxing music) compared to rest increased MEP amplitude (i.e., corticomotor excitability). Music Condition II as compared to Music Condition I (i.e., more activating music) reduced MEP variability (i.e., corticomotor variability). Finally, years of formal music training did not significantly influence corticomotor excitability while listening to music. Overall, results revealed that unfamiliar music modulates motor cortical excitability but is dependent upon the form of music and possibly music preference. These results will be used to inform planned studies in healthy older adults and people with Parkinson's disease.

The Feasibility of Group Therapeutic Singing Telehealth for Persons with Parkinson's Disease in Rural Iowa.

Introduction: Group therapeutic singing (GTS) may be an effective treatment for voice and respiratory impairments in persons with Parkinson's disease (PD). However, it remains unknown if GTS can be effectively delivered through telemedicine. Methods: Participants with PD from rural areas were recruited to complete a prerecorded GTS program, once a week for 8 weeks. Voice and respiratory outcome measures were collected 1 week before and 1 week after intervention. Results: Ten participants were enrolled in the study. One participant dropped at week 3. Five participants attended all eight sessions, two participants completed seven sessions, and one participant completed six sessions for 93.75% compliance. Statistical analysis for the data collected from the eight participants enrolled in the study revealed that voice outcome measures improved but did not reach significance. However, respiratory outcome measures significantly improved. Discussion: Results suggest that prerecorded GTS is feasible. Moreover, results are in keeping with results from a previous study using the exact same intervention with an in person therapist. Thus, this pilot work suggests that the use of prerecorded GTS may be a viable treatment option for those with limited access to care.

Repetitive finger movement and circle drawing in persons with Parkinson's disease.

Little is known regarding how repetitive finger movement performance impacts other fine motor control tasks, such as circle drawing, in persons with Parkinson's disease (PD). Previous research has shown that impairments in repetitive finger movements emerge at rates near to and above 2 Hz in most persons with PD. Thus, the purpose of this study was to compare circle drawing performance in persons with PD that demonstrate impairment in repetitive finger movement and those that do not. Twenty-two participants with PD and twelve healthy older adults completed the study. Only participants with PD completed the repetitive finger movement task. From the kinematic data for the repetitive finger movement task, participants were grouped into Hasteners and Non-Hasteners. Participants with PD and the healthy older adults completed a series of circle drawing tasks at two different target sizes (1 cm and 2 cm) and three pacing conditions (Self-paced, 1.25 Hz, and 2.5 Hz). Kinematic and electromyography data were recorded and compared between groups. Results revealed that, in general, persons with PD demonstrate impairments in circle drawing and associated electromyography activity compared to healthy older adults. Moreover, persons with PD that hasten during repetitive finger movements demonstrate significantly increased movement rate during circle drawing, while those persons with PD that do not hasten demonstrate a significant increase in width variability. This suggests that differing motor control mechanisms may play a role in the performance of fine motor tasks in persons with PD. Continued research is needed to better understand differences in circle drawing performance among persons with PD to inform future development of patient-centered treatments.

Sedentary Behavior and Quality of Life in Individuals With Parkinson's Disease.

Background. Sedentary behavior is a growing public health concern and may have particular relevance for the Parkinson disease (PD) population. However, the influence of sedentary time on factors associated with quality of life (QOL) in PD is unknown. The primary purpose of this study was to examine relationships between sedentary behaviors and markers of PD-specific QOL. A secondary purpose was to examine relationships between physical activity behaviors and QOL. Methods. We assessed sedentary and active behaviors using objective and interview measures and examined relationships between these behaviors and a measure of PD-specific QOL in individuals with PD. Results. Results demonstrated that sedentary time was significantly related to several aspects of QOL, including perceived deficits in the domains of mobility, cognitive processing, and communication. Additionally, results showed that time spent watching television was more strongly associated with lower levels of QOL than other more engaging sedentary activities. For physical activity, relationships between objective measures and QOL were weaker and only significantly associated with mobility. Time spent doing housework was associated with lower levels of QOL, whereas time spent in recreational activity was associated with lower levels of discomfort. Discussion. These results suggest that targeting decreases in sedentary behaviors (eg, reducing time spent watching television, breaking up prolonged bouts of sedentary time) may be effective for improving QOL in individuals with PD.

Repetitive Finger Movement and Dexterity Tasks in People With Parkinson's Disease.

BACKGROUND: Little is known regarding how repetitive finger movement performance, an assessment of bradykinesia (slowness of movement), is related to fine-motor dexterity tasks in people with Parkinson's disease (PD). OBJECTIVE: This pilot study examined the relationship between the performance of fine-motor dexterity tasks and repetitive finger movement in people with PD. METHOD: Forty-six participants with PD completed an acoustically cued repetitive finger movement task (1-3 Hz). Movement amplitude, movement rate difference, and coefficient of variation were obtained for each tone rate. Participants also completed a buttoning and Purdue pegboard assembly task. Buttoning time and number of assemblies were recorded. RESULTS: A significant association was found between movement rate difference and movement rate difference coefficient of variation and buttoning performance in which higher movement rate and higher variability were associated with slower buttoning times. No significant associations between any of the repetitive finger movement outcome measures and Purdue pegboard assembly performance were revealed. CONCLUSION: Changes in movement amplitude and movement rate may influence fine-motor dexterity tasks differently. Thus, it is important to consider the quantitative assessment of both movement rate and movement amplitude because they may indicate differential clinical applications in the treatment of people with PD.

The influence of moving with music on motor cortical activity.

Although there is a growing interest in using music to improve movement performance in various populations, there remains a need to better understand how music influences motor cortical activity. Listening to music is tightly linked to neural processes within the motor cortex and can modulate motor cortical activity in healthy young adult (HYAs). There is limited evidence regarding how moving to music modulates motor cortical activity. Thus, the purpose of this study was to explore the influence of moving to music on motor cortical activity in HYAs. Electroencephalography was collected while 32 HYAs tapped their index finger in time with a tone and with two contrasting music styles. Two movement rates were presented for each condition. Power spectra were obtained from data collected over the primary sensorimotor region and supplemental motor area and were compared between conditions. Results revealed a significant difference between both music conditions and the tone only condition for both the regions. For both music styles, power was increased in the beta band for low movement rates and increased in the alpha band for high movement rates. A secondary analysis determining the effect of music experience on motor cortical activity revealed a significant difference between musicians and non-musicians. Power in the beta band was increased across all conditions. The results of this study provide the initial step towards a more complete understanding of the neurophysiological underpinnings of music on movement performance which may inform future studies and therapeutic strategies.

The relationship between repetitive finger movement and quality of life in Parkinson's disease.

BACKGROUND: Repetitive finger movement significantly impacts daily living activities, but there have been limited studies determining how repetitive finger movement impacts quality of life (QOL) in persons with Parkinson's disease (PD). The purpose of this study was to determine the relationship between impairment in repetitive finger movement and QOL in persons with PD. METHODS: Eighty-four participants with PD completed a repetitive movement task and the Parkinson's Disease Questionnaire (PDQ). Structural equation modeling was used to determine the relationship between repetitive finger movement outcome measures of amplitude and movement rate difference and the domains of the PDQ. RESULTS: Including all repetitive finger outcome measures with demographic variables produced the strongest model for predicting QOL. DISCUSSION: Repetitive finger movement is associated with QOL, but more research is needed to better understand the relationship between repetitive finger movement variables and each specific QOL domain.

Influence of Music Style and Rate on Repetitive Finger Tapping.

Auditory cues, including music, are commonly used in the treatment of persons with Parkinson's disease. Yet, how music style and movement rate modulate movement performance in persons with Parkinson's disease have been neglected and remain limited in healthy young populations. The purpose of this study was to determine how music style and movement rate influence movement performance in healthy young adults. Healthy participants were asked to perform repetitive finger movements at two pacing rates (70 and 140 beats per minute) for the following conditions: (a) a tone only, (b) activating music, and (c) relaxing music. Electromyography, movement kinematics, and variability were collected. Results revealed that the provision of music, regardless of style, reduced amplitude variability at both pacing rates. Intermovement interval was longer, and acceleration variability was reduced during both music conditions at the lower pacing rate only. These results may prove beneficial for designing therapeutic interventions for persons with Parkinson's disease.

Experiences of Persons With Parkinson's Disease Engaged in Group Therapeutic Singing.

BACKGROUND: Parkinson's disease (PD) is a progressive neurodegenerative disorder that leads to altered neural control of movement, including the control of voice, respiration, and swallowing. There is a prevalent need to provide therapy for voice, respiration, and swallowing difficulties because current pharmacological and surgical treatments do not effectively treat these impairments. Previous research has demonstrated that singing may be a treatment option to target voice, respiratory, and swallowing impairments, as well as quality of life. However, participants' perspectives related to reasons for enrolling and engaging in programs as well as evaluation of singing programs have been neglected. OBJECTIVE: The purpose of this descriptive study was thus to solicit participants' views of their involvement in a group singing intervention (GSI) led by credentialed music therapists. METHODS: Twenty persons with PD were interviewed 4 to 6 months after completing the singing intervention. Participants were asked about 1) why they chose to participate, 2) what were the beneficial and non-beneficial aspects of participating, and 3) how to improve overall design and delivery of the GSI. RESULTS: Using content analysis procedures, we learned that participants regarded their involvement in the study as mutually beneficial, fun, and engaging. Participants appreciated the fellowship with other persons with PD and offered minimal constructive criticism. CONCLUSIONS: This study provided greater insight into how a therapeutic singing program may benefit participants and positively impact their lives.

Effects of singing on voice, respiratory control and quality of life in persons with Parkinson's disease.

Purpose Interventions focused on singing may provide additional benefits to established voice and respiratory therapies, due to their greater emphasis on the respiratory muscle control system in those with Parkinson's disease (PD) progresses. The purpose of this study was to examine if singing can improve voice, respiratory pressure and quality of life (QOL) in persons with PD. Methods This pilot study measured the effects of a singing intervention in 27 participants with PD. Participants were assigned to a high (met twice weekly) or low (met once weekly) dosage group. Voice, respiratory and QOL measures were recorded before and after an 8-week singing intervention. Sessions were led by board-certified music therapists and included a series of vocal and articulation exercises and group singing. Results Both groups demonstrated significant improvements in maximum inspiratory and expiratory pressure, as well as phonation time. While other voice measures improved, they did not reach statistical significance. Voice QOL and whole health QOL also significantly improved. Conclusion These results suggest singing may be a beneficial and engaging treatment choice for improving and maintaining vocal function and respiratory pressure in persons with PD. Implications for Rehabilitation In a small sample, group singing proved beneficial for improving voice and respiratory impairment in persons with Parkinson's disease. Completing group singing one time per week for 8 weeks was as effective as completing group singing two times per week for 8 weeks in persons with Parkinson's disease. Group singing is an effective means of improving overall quality of life in persons with Parkinson's disease.

Altered premotor cortical oscillations during repetitive movement in persons with Parkinson's disease.

Premotor areas play a critical role in the control of repetitive movements. While research has shown that movement-related oscillations are abnormal during repetitive movements in persons with Parkinson's disease (PD), there is limited research examining the contribution of premotor areas, such as the contralateral dorsal premotor area (PMd) and supplementary motor area (SMA), to this impairment. This study compared movement-related oscillations over premotor regions between participants with PD and control participants. Nine participants with PD off and on medication and nine matched control participants were studied. Participants performed cued index finger movements. Spectral power was derived from electroencephalographic recordings from electrodes FC3/FC4 and Cz over the regions of the contralateral PMd and SMA respectively. Movement-related alpha and beta band oscillations were suppressed over electrode FC3/FC4 (contralateral PMd) in participants with PD, particularly at higher movement rates, in both the off and on medication conditions compared to control subjects. The pattern of movement-related oscillations recorded from Cz (SMA) was similar between PD and control groups. This would suggest that the region of the contralateral PMd may be preferentially involved with the control of externally cued repetitive movements and that changes in this activity may contribute to the deterioration of repetitive finger movements at higher rates in persons with PD.

Motor cortical oscillations are abnormally suppressed during repetitive movement in patients with Parkinson's disease.

OBJECTIVE: Impaired repetitive movement in persons with Parkinson's disease (PD) is associated with reduced amplitude, paradoxical hastening and hesitations or arrest at higher movement rates. This study examined the effects of movement rate and medication on movement-related cortical oscillations in persons with PD. METHODS: Nine participants with PD were studied off and on medication and compared to nine control participants. Participants performed index finger movements cued by tones from 1 to 3 Hz. Movement-related oscillations were derived from electroencephalographic recordings over the region of the contralateral sensorimotor cortex (S1/M1) during rest, listening, or synchronized movement. RESULTS: At rest, spectral power recorded over the region of the contralateral S1/M1 was increased in the alpha band and decreased in the beta band in participants with PD relative to controls. During movement, the level of alpha and beta band power relative to baseline was significantly reduced in the PD group, off and on medication, compared to controls. Reduced movement amplitude and hastening at movement rates near 2 Hz was associated with abnormally suppressed and persistent desynchronization of oscillations in alpha and beta bands. CONCLUSION: Motor cortical oscillations in the alpha and beta bands are abnormally suppressed in PD, particularly during higher rate movements. SIGNIFICANCE: These findings contribute to the understanding of mechanisms underlying impaired repetitive movement in PD.

Discriminating features of gait performance in progressive supranuclear palsy.

INTRODUCTION: Progressive supranuclear palsy (PSP) is the most common form of atypical Parkinsonism; however it is underdiagnosed and often misdiagnosed as Parkinson's disease (PD). METHODS: We investigated gait initiation (GI) and gait performance in a total of 36 participants (12 PSP, 12 PD and 12 healthy age- and gender-matched controls) to gain further insight into specific motor deficits that characterize dynamic postural control and gait in PSP. Anticipatory postural adjustments (APAs), quantified by center of pressure (COP) displacement and speed prior to an initial heel off, and the maximum distance (COPCOM) between COP and center of mass (COM) during all three GI phases were calculated to evaluate dynamic postural control. Steady-state gait performance was also evaluated and compared across the groups. RESULTS: APAs in PSP were significantly altered such that the posterior COP shift is profoundly diminished when compared to PD (p < 0.05). Moreover, proper velocity control during GI in PSP was affected, particularly in the mediolateral direction, when compared to PD (p < 0.05). The diminished COPCOM distance is further indicative of more severe dynamic postural instability in PSP than in PD (p < 0.05). Significant differences in spatiotemporal parameters, inter-step variability, and asymmetry during gait in PSP, in comparison with PD were also identified (all p's < 0.05). CONCLUSION: The present study reveals that the compensatory GI strategy in PSP is distinct from PD and paradoxically induces lateral instability. Further, gait performance in PSP is slower and more variable which could be the consequence of lateral instability and fear of falling.