Visual Function During Gait in Parkinson's Disease: Impact of Cognition and Response to Visual Cues
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 100
- 试验地点
- 1
- 主要终点
- Visual Sampling Parameter: Saccade Frequency During Gait
研究概览
简要总结
Parkinson's disease (PD) is associated with problems of gait such as veering, difficulty turning, an inability to perceive doorways or obstacles, and negotiate uneven terrain. Gait problems, especially veering, may be exacerbated by visuospatial dysfunction which predispose to falls, freezing and festination of gait. Visuospatial dysfunction is common in PD and likely involves peripheral features (e.g. contrast sensitivity) as well as central cognitive mechanisms (e.g. attention).
Central neuro-degeneration in PD, PD dementia, and dementia with Lewy Bodies may influence visual function, as impaired visual sampling has been reported in these conditions. Visual sampling is measured via saccadic (fast eye movement) activity, as saccades are the mechanisms through which people orientate and explore the environment. The use of objective devices to reliably measure saccades is important to detect disease related eye movement changes. Emerging visuomotor research has measured visual sampling in PD using devices such as electrooculography and infra-red eye tracking, revealing reduced amplitude, speed and frequency of saccades during various tasks.
Despite recent increases in visuomotor research it remains unclear how PD influences visual sampling of the environment during gait and the influence of attentional and cognitive deficits. Recent work demonstrated that people with PD sample their environment less frequently than controls, despite a slower gait. Saccadic timing was unchanged in response to environmental cues. Despite this, environmental visual cues (transverse lines on the floor) have been shown to increase the number of fixations made during gait. However the mechanisms of this response remain unclear. Cognition is likely of importance, with response potentially influenced by attentional control.
This observational study aims to examine the influence of cognition on visuomotor control during gait in PD. This aim will be achieved by observation of visual sampling under several environmental challenges (straight walk, doorways, turns, visual cue) and a dual task.
详细描述
This is an observational study of visual sampling during gait under different environmental challenge (straight, doorway, turn and visual cue (transverse lines on the floor)) and dual task. These conditions represent everyday activities/environments which can be difficult for people with PD.
This is not an interventional study as participants are not assigned to any specific interventions by the researchers, or followed up to re-assess outcomes other than for reliability testing of the eye-tracking devices used. The study has been ethically approved (NRES Committee North East - Newcastle & North Tyneside 1: 13/NE/0128) as an observational study as participants are assigned to pre-defined groups, and have behavioural measures (primarily visual sampling and secondly gait) observed in the gait laboratory under various walking conditions common to everyday environments.
Study Hypotheses
The over-arching hypothesis of this observational study is that visual sampling during gait in PD will be influenced by cognitive impairments. This study hypothesises that saccadic activity will be restricted in PD compared to controls during gait. Dual task and environmental challenge via a doorway, turn or visual cue will influence saccadic activity during gait.
Specific study hypothesises are:
研究设计
- 研究类型
- Observational
- 观察模型
- Case Control
- 时间视角
- Cross Sectional
入排标准
- 年龄范围
- 50 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Common to all groups
- •Aged ≥50 years
- •Able to walk unaided
- •Adequate hearing (as evaluated by the whisper test; stand 2m behind participant and whisper a 2 syllable word, participant repeats word) and vision capabilities (as measured using a Snellen chart - 6/18-6/12).
- •Stable medication for the past 1 month and anticipated over a period of 6 months
- •Group Specific Criteria
- •Participants with PD:
- •Diagnosis of idiopathic PD, as defined by the UK Brain Bank criteria
- •Hoehn and Yahr stage I-III
- •Stable medication for past 1 month and anticipated over next 6 months or stable Deep Brain Stimulation for at least one month and expected following 6 months
- •Score ≥21/30 on Montreal cognitive assessment (MoCA) which is used to classify non-demented PD (PD dementia is <21/30)
- •Free from any neurological disorders that may have caused cognitive impairment
- •No restriction was made for medication usage and participants on stable doses of medication or treatment were permitted.
排除标准
- •Common to all groups
- •Psychiatric co-morbidity (e.g., major depressive disorder as determined by geriatric depression scale (GDS-15); >10/15)
- •Clinical diagnosis of dementia or other severe cognitive impairment (PD = MoCA <21/30, Controls = MoCA <26/30)
- •History of stroke, traumatic brain injury or other neurological disorders (other than PD, for that group)
- •Acute lower back or lower extremity pain, peripheral neuropathy, rheumatic and orthopaedic diseases
- •Unstable medical condition including cardio-vascular instability in the past 6 months
- •Unable to comply with the testing protocol or currently participating in another interfering research project
- •Interfering therapy
- •Vision specific Criteria
- •Any pupillary diameter disorder; such as significantly non-round pupils, Adies pupil (tonic or dilated pupil), Argyll-Robertson pupil (absence of light reaction), unilateral small pupil
- •Neuromotility disorders, such as Nystagmus or other ocular oscillations
- •Significant left eye disorders (i.e. squint, twitching, Ptosis [drooping eyelids])
- •Known significant visual field deficits; such as hemianopia
- •Optic nerve disease
- •Optic disc elevation
- •Optic disc swelling; such as Papilledema or Papillitis
结局指标
主要结局
Visual Sampling Parameter: Saccade Frequency During Gait
时间窗: Session 1: observation during gait assessments (lasting approx. 90mins)
Number of fast eye movements made per second observed when walking, measured via EOG and Dikablis mobile eye-tracker. Walking conditions include; single task, dual task, through a doorway, whilst turning and with a visual cue in place.
次要结局
- Visual Sampling Parameter: Saccade Duration During Gait(Session 1: observation during gait assessments (lasting approx. 90mins))
- Gait Parameter: Single Support Time(Session 1: observation during gait assessments (lasting approx. 90mins))
- Visual Sampling Parameter: Saccade Number During Gait(Session 1: observation during gait assessments (lasting approx. 90mins) and one week later in Session 2 for a sub-group (PD and controls n = upto 25) (lasting approx. 60mins))
- Visual Sampling Parameter: Saccade Acceleration During Gait(Session 1: observation during gait assessments (lasting approx. 90mins))
- Gait Parameter: Gait Speed(Session 1: observation during gait assessments (lasting approx. 90mins))
- Gait Parameter: Step Length(Session 1: observation during gait assessments (lasting approx. 90mins))
- Gait Parameter: Step Time(Session 1: observation during gait assessments (lasting approx. 90mins) and one week later in Session 2 for a sub-group (PD and controls n = upto 25) (lasting approx. 60mins))
- Gait Parameter: Double Support Time(Session 1: observation during gait assessments (lasting approx. 90mins))
- Visual Sampling Parameter: Saccade Velocity During Gait(Session 1: observation during gait assessments (lasting approx. 90mins))
- Visual Sampling Parameter: Saccade Amplitude During Gait(Session 1: observation during gait assessments (lasting approx. 90mins))
- Visual Sampling Parameter: Fixation Number During Gait(Session 1: observation during gait assessments (lasting approx. 90mins))
- Visual Sampling Parameter: Fixation Duration During Gait(Session 1: observation during gait assessments (lasting approx. 90mins))
- Visual Sampling Parameter: Number of Blinks During Gait(Session 1: observation during gait assessments (lasting approx. 90mins) and one week later in Session 2 for a sub-group (PD and controls n = upto 25) (lasting approx. 60mins))