Development and testing of an MR-compatible tactile stimulator system: Application for individuals with a brain injury

Abstract

Background:

Accurate tactile perception is essential for daily function. Abnormally perceiving tactile stimuli is associated with poorer movement recovery in individuals post brain injury. The mechanisms causing abnormal tactile perception post brain injury remain incompletely understood, partially due to insufficient examination methods. Here, we present a custom tactile stimulator system that enables examination of how abnormal tactile perception arises post brain injury.

New Method:

The novel tactile stimulator pneumatically inflates and deflates a membrane to stimulate the skin via a small circular contact area (diameter: $\sim$4–5 mm). The tactile stimulator is compact (14 mm length$\times$6.5 mm height), compatible with magnetic resonance imaging (MRI), and precise in automatically applying low intensity forces (1.1–2.5 N) in the MRI.

Results:

Feedback on a Likert 5-point scale from 14 young adults who are neurotypical during an MRI study with the tactile stimulator identified comfort in feeling the applied force stimuli as most comfortable (score: 5) and second most comfortable (score: 4) for 11 and 3 participants, respectively. The force stimuli activated the contralateral primary somatosensory cortex and bilateral secondary somatosensory cortices.

Comparison with Existing Methods:

Unlike existing tools, our system combines a compact size, precise control of a range of forces, and a relatively fixed contact area.

Conclusions:

The novel tactile stimulator system can enable high-precision studies that lead to a better understanding of the brain processes governing tactile perceptual dysfunction in patient populations, including those living with a brain injury.