"The whole perimeter is difficult": Parkinson's disease and the conscious experience of walking in everyday environments

Multisensory mechanisms of gait and balance in Parkinson's disease: an integrative review

Understanding the neural underpinning of human gait and balance is one of the most pertinent challenges for 21st-century translational neuroscience due to the profound impact that falls and mobility disturbances have on our aging population. Posture and gait control does not happen automatically, as previously believed, but rather requires continuous involvement of central nervous mechanisms. To effectively exert control over the body, the brain must integrate multiple streams of sensory information, including visual, vestibular, and somatosensory signals. The mechanisms which underpin the integration of these multisensory signals are the principal topic of the present work. Existing multisensory integration theories focus on how failure of cognitive processes thought to be involved in multisensory integration leads to falls in older adults. Insufficient emphasis, however, has been placed on specific contributions of individual sensory modalities to multisensory integration processes and cross-modal interactions that occur between the sensory modalities in relation to gait and balance. In the present work, we review the contributions of somatosensory, visual, and vestibular modalities, along with their multisensory intersections to gait and balance in older adults and patients with Parkinson's disease. We also review evidence of vestibular contributions to multisensory temporal binding windows, previously shown to be highly pertinent to fall risk in older adults. Lastly, we relate multisensory vestibular mechanisms to potential neural substrates, both at the level of neurobiology (concerning positron emission tomography imaging) and at the level of electrophysiology (concerning electroencephalography). We hope that this integrative review, drawing influence across multiple subdisciplines of neuroscience, paves the way for novel research directions and therapeutic neuromodulatory approaches, to improve the lives of older adults and patients with neurodegenerative diseases.

Telephone-based application of the Activities of Daily Living Questionnaire in patients with Parkinson's disease

BACKGROUND

 The Activities of Daily Living Questionnaire (ADLQ) focuses on assessing the ability to perform activities of daily living (ADLs) based on the self-perception of individuals with Parkinson's disease (PD). A Brazilian Portuguese version of the questionnaire is available (ADLQ-Brazil), and further investigation is needed to fully assess its measurement properties.

OBJECTIVE

 To investigate construct and concurrent validity of the telephone-based administration of the ADLQ-Brazil with community individuals with PD.

METHODS

 There were 50 adults with PD (mean age: 68 ± 9.5 years) invited to answer the ADLQ-Brazil on two randomized occasions, face-to-face and by telephone, 7 to 10 days apart. Clinical-based measures including the Movement Disorder Society-Sponsored Revision of the Unified Parkinson Disease Rating Scale, Timed Up and Go Test, Nine Hole Peg Test, Mini-Balance Evaluation Systems Test, Apathy Scale, Beck Depression Inventory, Modified Fatigue Impact Scale, and Parkinson Disease Quality of Life Questionnaire were applied during the first session, to establish construct validity.

RESULTS

 The total scores on the ADLQ-Brazil were significantly associated with the clinical-based measures, thus providing evidence of construct validity. No significant differences were observed between the mean scores obtained with the face-to-face and telephone-based administration of the questionnaire (95%CI = 0.997). A high level of agreement was found in the total scores obtained between both applications of the ADLQ-Brazil (95%CI = 0.994-0.998), and most of the individual items had, on average, moderate agreement.

CONCLUSION

 The findings provide psychometric support for the ADLQ-Brazil as a telephone interview to assess the performance of ADLs in individuals with PD.

'Le regard des autres': the experience of walking in social environments as a person with Parkinson's disease

OBJECTIVE

To examine the experience of people with Parkinson's disease when walking in different social situations, and improve understanding of how this affects participation in meaningful activity.

METHODS

A convenience sample of fourteen people with Parkinson's disease and a history of gait dysfunction was recruited. In-depth interviews and direct observations were conducted in the participants' home environments. Specific examples from community mobility were reviewed using first person interviewing techniques with the support of video footage. Interview transcripts were analyzed using an interpretive phenomenological approach to derive key themes.

RESULTS

The feeling of 'being looked at' (le regard des autres) was the central theme in participant discourse. This sentiment was inextricably linked to the given norms of the social setting, and the relationships between participants and others within that environment. Participants sought to manage how they were perceived by others through modification of posture/gait patterns; disclosure of their neurological disease; and avoidance/withdrawal from social situations.

CONCLUSION

Further to the functional aspects of mobility, gait is important for maintaining self-image in people with Parkinson's disease. Affective gaze interactions have significant consequences upon participation restriction. These findings underscore the interest of activities which strengthen self-image and validate movement diversity in PD rehabilitation.

Abnormal eye movements in Parkinson's disease: From experimental study to clinical application

Parkinson's disease (PD) is a neurodegenerative disease that integrates a series of motor symptoms and non-motor symptoms, making early recognition challenging. The exploration of biomarkers is urgently required. Abnormal eye movements in PD have been reported to appear in a variety of ways since eye tracking technology was developed, such as decreased saccade amplitude, extended saccade latency, and unique saccade patterns. Non-invasive, objective and simple eye tracking has the potential to provide effective biomarkers for the PD diagnosis, progression and cognitive impairment, as well as ideas for research into the occurrence and treatment strategy of motor symptoms. In this review, we introduced the fundamental eye movement patterns and typical eye movement paradigms (such as fixation, pro-saccade, anti-saccade, smooth tracking, and visual search), summarized the symptoms of various ocular motor abnormalities in PD, and discussed the research implications of oculomotor investigation to the pathogenesis of PD and related motor symptoms, as well as the clinical implications as biomarkers and its inspiration on treatment.

Listening to the patients' voice: a conceptual framework of the walking experience

BACKGROUND

walking is crucial for an active and healthy ageing, but the perspectives of individuals living with walking impairment are still poorly understood.

OBJECTIVES

to identify and synthesise evidence describing walking as experienced by adults living with mobility-impairing health conditions and to propose an empirical conceptual framework of walking experience.

METHODS

we performed a systematic review and meta-ethnography of qualitative evidence, searching seven electronic databases for records that explored personal experiences of walking in individuals living with conditions of diverse aetiology. Conditions included Parkinson's disease, multiple sclerosis, chronic obstructive pulmonary disease, hip fracture, heart failure, frailty and sarcopenia. Data were extracted, critically appraised using the NICE quality checklist and synthesised using standardised best practices.

RESULTS

from 2,552 unique records, 117 were eligible. Walking experience was similar across conditions and described by seven themes: (i) becoming aware of the personal walking experience, (ii) the walking experience as a link between individuals' activities and sense of self, (iii) the physical walking experience, (iv) the mental and emotional walking experience, (v) the social walking experience, (vi) the context of the walking experience and (vii) behavioural and attitudinal adaptations resulting from the walking experience. We propose a novel conceptual framework that visually represents the walking experience, informed by the interplay between these themes.

CONCLUSION

a multi-faceted and dynamic experience of walking was common across health conditions. Our conceptual framework of the walking experience provides a novel theoretical structure for patient-centred clinical practice, research and public health.

People with Parkinson's disease and housing issues: A scoping review

BACKGROUND AND AIMS

There is evidence that housing issues are associated with health outcomes as people age, but little is known in this respect regarding the specific population of people with Parkinson's disease (PD). The objective of this literature review was to identify and analyze the knowledge gap concerning people with PD and housing issues.

METHODS

Applying established guidelines for scoping reviews, a systematic literature search was done in relevant databases applying the following inclusion criteria: empirical studies including human participants with PD, addressing housing in the objective, hypothesis or research questions, and published in English in peer-reviewed journals. Data were analyzed using a framework of domains, factors, and variables influencing housing decisions among older people.

RESULTS

Twelve publications were identified, originating from a few researchers and with very different scopes. While the social dimension was scarcely attended to, the publications addressed all six domains of the analytical framework and 30% of the variables specified therein, but many were only used for descriptive purposes.

CONCLUSION

This scoping review reveals that there is a substantial knowledge gap regarding people with PD and housing issues. The knowledge gap is most evident in the social dimension, while the studies identified provide more information relating to the health dimension than what is the case in research on housing targeting the general aging population. Because society urgently needs evidence to support the development of housing policies and provide suitable housing for this vulnerable population, more research targeting people with PD and housing issues is warranted.

Walking on common ground: a cross-disciplinary scoping review on the clinical utility of digital mobility outcomes

Physical mobility is essential to health, and patients often rate it as a high-priority clinical outcome. Digital mobility outcomes (DMOs), such as real-world gait speed or step count, show promise as clinical measures in many medical conditions. However, current research is nascent and fragmented by discipline. This scoping review maps existing evidence on the clinical utility of DMOs, identifying commonalities across traditional disciplinary divides. In November 2019, 11 databases were searched for records investigating the validity and responsiveness of 34 DMOs in four diverse medical conditions (Parkinson's disease, multiple sclerosis, chronic obstructive pulmonary disease, hip fracture). Searches yielded 19,672 unique records. After screening, 855 records representing 775 studies were included and charted in systematic maps. Studies frequently investigated gait speed (70.4% of studies), step length (30.7%), cadence (21.4%), and daily step count (20.7%). They studied differences between healthy and pathological gait (36.4%), associations between DMOs and clinical measures (48.8%) or outcomes (4.3%), and responsiveness to interventions (26.8%). Gait speed, step length, cadence, step time and step count exhibited consistent evidence of validity and responsiveness in multiple conditions, although the evidence was inconsistent or lacking for other DMOs. If DMOs are to be adopted as mainstream tools, further work is needed to establish their predictive validity, responsiveness, and ecological validity. Cross-disciplinary efforts to align methodology and validate DMOs may facilitate their adoption into clinical practice.

Perceived walking difficulties in Parkinson's disease - predictors and changes over time

BACKGROUND

People with Parkinson's disease (PD) have described their walking difficulties as linked to activity avoidance, social isolation, reduced independence and quality of life. There is a knowledge gap regarding predictive factors of perceived walking difficulties in people with PD. Such knowledge could be useful when designing intervention studies. This study aimed to investigate how perceived walking difficulties evolve over a 3-year period in people with PD. A specific aim was to identify predictive factors of perceived walking difficulties.

METHODS

One hundred forty-eight people with PD (mean age 67.9 years) completed the Generic Walk-12 (Walk-12G) questionnaire (which assesses perceived walking difficulties) at both baseline and the 3-year follow-up. Paired samples t-test was used for comparing baseline and follow-up mean scores. Multivariable linear regression analyses were used to identify predictive factors of perceived walking difficulties.

RESULTS

Perceived walking difficulties increased after 3 years: mean Walk-12G score 14.8 versus 18.7, p < 0.001. Concerns about falling was the strongest predictor (β = 0.445) of perceived walking difficulties, followed by perceived balance problems while dual tasking (β = 0.268) and pain (β = 0.153). Perceived balance problems while dual tasking was the strongest predictor (β = 0.180) of a change in perceived walking difficulties, followed by global cognitive functioning (β = - 0.107).

CONCLUSIONS

Perceived walking difficulties increase over time in people with PD. Both personal factors (i.e. concerns about falling) and motor aspects (i.e. balance problems while dual tasking) seem to have a predictive role. Importantly, our study indicates that also non-motor symptoms (e.g. pain and cognitive functioning) seem to be of importance for future perceived walking difficulties. Future intervention studies that address these factors need to confirm their preventative effect on perceived walking difficulties.

Visuomotor control of walking in Parkinson's disease: Exploring possible links between conscious movement processing and freezing of gait

INTRODUCTION

Changes in visual attention have been argued to influence freezing of gait (FOG) in people with Parkinson's Disease (PD). However, the specific visual search patterns of people with FOG pathology (PD + FOG) and potential underlying mechanisms are not well understood. The current study explored visual search behavior in PD + FOG while walking on a pathway featuring environmental features known to exacerbate FOG (e.g., narrow doorway and tripping hazards). Potential underpinning attentional mechanisms were also assessed, such as conscious movement processing.

METHODS

Visual search behavior of twelve people with PD + FOG tested in ON-state (M_age = 74.3) and twelve age-matched healthy controls (M_age = 72.5) were analyzed during a complex walking task. The task required participants to step over an obstacle and navigate through a narrow doorway, surrounded by clutter.

RESULTS

People with PD + FOG more frequently directed visual attention to ongoing and imminent steps compared to healthy controls (Mdn = 26% vs Mdn = 14%, respectively; p = 0.042). Self-reported conscious movement processing was also significantly higher in people with PD + FOG. The one participant who froze during the walking task fixated the future trip hazard (obstacle, approximately 6 steps ahead) almost exclusively during freezing trials (i.e., 60-100% of the trial). In contrast, during 'non-freeze' trials, this participant increased the duration of fixations towards ongoing and imminent steps.

CONCLUSION

Results suggest that people with PD + FOG strongly monitor/control ongoing and immediately upcoming stepping movements. However, prolonged fixations towards threats to future movements might prevent people with PD + FOG from processing the visual information needed to do this, thereby provoke freezing episodes.