Verticality Perception Assessed by the Haptic Vertical

University of Zurich19 enrolled

Overview

The investigators previously shown that a rotating optokinetic stimulus results in shifts of the subjective visual vertical in healthy human subjects. However, the origin of these shifts is still poorly understood. Both torsional displacement of the eyes and a shift in the internal estimate of direction of gravity have been proposed as potential explanations. Here the investigators use a vision-independent setup to differentiate between these two hypotheses, predicting no impact of a rotating stimulus on the subjective haptic vertical if torsion triggers the shift.

Study Type

INTERVENTIONAL

Allocation

Purpose

BASIC_SCIENCE

Masking

NONE

Enrollment

Conditions

Healthy

Interventions

changes in whole-body roll position and visual/haptic stimuli presentedOTHER

In different whole-body roll positions subjects will be presented a luminous line or a rod in combination with a moving or stationary background. Participants will be asked to align the line or the rod along perceived direction of gravity.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * ages 18-65 years * informed consent * absence of exclusion criteria Exclusion Criteria: * peripheral-vestibular deficit * disturbed consciousness * history of sensory deficits * visual field deficits * other neurological or systemic disorder which can cause dementia or cognitive dysfunction * intake of antidepressants, sedatives, or neuroleptics * pregnancy, unless excluded by a negative pregnancy test * known neck pain or status post neck trauma

Locations (1)

University Hospital Zurich, Dept. of Neurology

Zurich, Canton of Zurich, Switzerland

Outcomes

Primary Outcomes

Adjustment errors of aligning a rod along perceived direction of gravity while an optokinetic stimulus is presented.

This outcome parameter focuses on the adjustment errors of the subjective haptic vertical while presenting a visual bias (i.e. an optokinetic rotatory stimulus).

Time frame: 60 minutes

Trial-to-trial variability of aligning a rod along perceived direction of gravity while an optokinetic stimulus is presented.

This outcome parameter focuses on the trial-to-trial variability of rod alignments along perceived direction of gravity when presenting a visual bias cue (i.e. an optokinetic rotatory stimulus).

Time frame: 60 minutes

Secondary Outcomes

Comparison of adjustment errors between the subjective haptic vertical and the subjective visual vertical

Time frame: 60 minutes

Comparison of adjustment errors of perceived vertical using the subjective haptic vertical with and without presenting an optokinetic stimulus

Time frame: 60 minutes

Data from ClinicalTrials.gov

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