Somatosensory Dysfunction as the Underlying Mechanism of Upper Limbs Motor Blocks in People With Parkinson's Disease

Summary

Motor blocks during gait and upper limb movements (FOULs) are a disabling and common motor impairment in mild to severe stages of Parkinson's disease (PD). However, the main mechanism underlying these phenomena is still an open debate. Apart from the motor correlates, cognitive-attentional impairment and somatosensory deficits (especially in the proprioceptive system) may underlie these motor blocks. The current study aims to unravel whether the proprioceptive system is involved by manipulating task-relevant or non-relevant proprioceptive stimuli.

Hence, the main aims of this study are:

(i) to assess the somatosensory function in people with PD that experience freezing of gait FOG and (ii) to investigate the effects of manipulating both proprioception and attentional resources on FOUL severity.

Forty-five people will be assigned to three age-matched groups (N=15 each): healthy elderly, PD patients that experience FOG (FOG+) and PD patients that do not experience FOG. Cutaneous sensory function and kinesthetic ability will be assessed by means of standardized user-friendly methods and precise repositioning measures using the VICON motion analysis. Additionally, participants will perform a newly developed task that can successfully elicit FOULs (a handwriting freezing-provoking task) on a custom tablet (Heremans et al 2015). The task will be performed without and with the use of muscle vibration (a well-known method to stimulate the proprioceptive system). The investigators will manipulate both the timing of vibration (relevant - after FOUL onset; or non-relevant: before FOUL onset) and the region of stimulation (neutral: on a bone-mark where there is little if any proprioceptive stimulation; and on a non-neutral spot: on the forearm muscles). It is believed that FOG+ will present with worse somatosensory function than those who do not experience motor blocks (especially in the proprioceptive system). Additionally, the Investigators expect a reduction in FOUL severity (e.g. FOUL duration) when vibration is applied in a task-relevant way, independently of the region stimulated. In contrast, it is also expected that when vibration is applied in a non-relevant way and it may act as a distractor, FOUL duration will increase. This study will thus be able to distinguish between the contribution of attentional and proprioceptive resources to the mechanism of motor blocks in PD.

Conditions

• Parkinson's Disease
• Somatosensory Disorders

Interventions

DEVICE

Mechanical stimulus (vibration) applied on the forearm

Local vibration will be applied using a custom-made vibratory system (named Vibrators) consisted of small vibratory devices (constructed using DC micro motors (Faulhaber® - Switzerland) bearing an eccentric load, enclosure on a PVC involucre). Vibrators measure 4.5cm x 2cm x 2cm and weight 27-31g each. Vibrators were custom-made especially for this study and therefore do not have a trade name. Vibrators will be positioned either on the extensor carpi radialis brevis (ECRB) muscle belly or on the olecranon region. Devices will be kept in place using regular elbow elastic supports.

Sponsors & Collaborators

• Conselho Nacional de Desenvolvimento Científico e Tecnológico

  collaborator OTHER_GOV

• Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.

  collaborator OTHER_GOV

• KU Leuven

  lead OTHER

Principal Investigators

• Alice Nieuwboer, Professor · KU Leuven

Study Design

Allocation

RANDOMIZED

Purpose

SCREENING

Masking

SINGLE

Model

PARALLEL

Eligibility

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2016-01-31

Primary Completion

2016-03-31

Completion

2016-07-31

Countries

• Belgium

Study Locations