Abnormal Movements, Cerebellum and Sensorimotor : Oculomotor Study

Summary

Dystonia is a movement disorder characterized by involuntary, sustained, often repetitive muscle contractions of opposite muscles that lead to abnormal twisting movements or odd postures. Essential tremor is a slowly progressive neurologic disorder characterized by the appearance of a tremor during the voluntary movement. The pathophysiology of dystonia or essential tremor is not fully elucidated. Dystonia and essential tremor are associated with dysfunction of the sensorimotor basal ganglia-cortical network and involvement of the cerebellum and cerebellar pathways has also been recently suggested.

The investigators propose to study 30 patients having a primary dystonia (15 DYT11 genetically documented), 15 patients having an essential tremor without deep brain stimulation and 15 patients having an essential tremor with deep brain stimulation.A group of 30 healthy volunteers will be recruited and tested according to the same modalities. They will be paired in sex and age. 30 patients having a Parkinson disease will be also tested.

Eye position will be sampled with a video-based monocular eye tracker (SMI, Germany) before and immediately after an adaptation task. Saccade adaptation is evaluated as the percentage change in the mean saccade amplitude between pre-test and post-test.

Expected results:

* no or fewer alteration of the performance to the adaptation task in the Parkinson group than in the Essential Tremor group/ dystonia group.
* abnormal reactive saccade backward adaptation in the Dystonia group and Essential Tremor group, providing further neurophysiological evidence of cerebellar dysfunction.

Conditions

• Healthy
• Dystonia
• Parkinson Disease

Interventions

DEVICE

Tracking eye movement

Device: studying Saccadic eye movements with a video eye tracker: The subjects are seated in darkness facing a screen located 60 cm before their eyes, their chin on a chin strap and their forehead placed against a frontal support. Eye position is sampled at 500 Hz with a video-based monocular eye tracker (SMI, Germany). Each recording session start with a calibration test in which the subjects looked at nine consecutive targets covering the entire visual field, as used during the oculomotor paradigms: four experimental conditions: a visually guided saccade task, a pre-test, a backward adaptation task, and a post-test. The pre-test and post-test (40 trials each) are performed before and immediately after the backward adaptation task, in the same conditions, except that the target was extinguished when the velocity threshold (150°/s for 10 ms) is reached, instead of jumping to a new location.

DEVICE

Tracking eye movement under deep brain stimulation

Device: studying Saccadic eye movements with a video eye tracker. If the patient has deep brain stimulation, recording will be made in the morning, before the usual morning start of the deep brain stimulation.

Sponsors & Collaborators

• Institut National de la Santé Et de la Recherche Médicale, France

  lead OTHER_GOV

Principal Investigators

• Emmanuel Flamand-Roze, MD, PhD · Institut National de la Santé Et de la Recherche Médicale, France

Study Design

Allocation

NON_RANDOMIZED

Purpose

DIAGNOSTIC

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2011-03-31

Primary Completion

2014-03-31

Completion

2014-03-31

Countries

• France

Study Locations