Evaluating Sensory Acuity as a Marker of Balance Dysfunction After a Traumatic Brain Injury: A Psychophysical Approach

Rakesh Pilkar; Kiran K Karunakaran; Akhila Veerubhotla; Naphtaly Ehrenberg; Oluwaseun Ibironke; Karen J Nolan

doi:10.3389/fnins.2020.00836

Evaluating Sensory Acuity as a Marker of Balance Dysfunction After a Traumatic Brain Injury: A Psychophysical Approach

Front Neurosci. 2020 Aug 11:14:836. doi: 10.3389/fnins.2020.00836. eCollection 2020.

Authors

Rakesh Pilkar^{1

2}, Kiran K Karunakaran^{1

3

4}, Akhila Veerubhotla^{1

2}, Naphtaly Ehrenberg¹, Oluwaseun Ibironke¹, Karen J Nolan^{1

2

4}

Affiliations

¹ Center for Mobility and Rehabilitation Engineering Research, Kessler Foundation, West Orange, NJ, United States.
² Department of Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School, Newark, NJ, United States.
³ New Jersey Institute of Technology, Newark, NJ, United States.
⁴ Children's Specialized Hospital, New Brunswick, NJ, United States.

Abstract

There is limited research on sensory acuity i.e., ability to perceive external perturbations via body-sway during standing in individuals with a traumatic brain injury (TBI). It is unclear whether sensory acuity diminishes after a TBI and if it is a contributing factor to balance dysfunction. The objective of this investigation is to first objectively quantify the sensory acuity in terms of perturbation perception threshold (PPT) and determine if it is related to functional outcomes of static and dynamic balance. Ten individuals with chronic TBI and 11 age-matched healthy controls (HC) performed PPT assessments at 0.33, 0.5, and 1 Hz horizontal perturbations to the base of support in the anterior-posterior direction, and a battery of functional assessments of static and dynamic balance and mobility [Berg balance scale (BBS), timed-up and go (TUG) and 5-m (5MWT) and 10-m walk test (10MWT)]. A psychophysical approach based on Single Interval Adjustment Matrix Protocol (SIAM), i.e., a yes-no task, was used to quantify the multi-sensory thresholds of perceived external perturbations to calculate PPT. A mixed-design analysis of variance (ANOVA) and post-hoc analyses were performed using independent and paired t-tests to evaluate within and between-group differences. Pearson correlation was computed to determine the relationship between the PPT and functional measures. The PPT values were significantly higher for the TBI group (0.33 Hz: 2.97 ± 1.0, 0.5 Hz: 2.39 ± 0.7, 1 Hz: 1.22 ± 0.4) compared to the HC group (0.33 Hz: 1.03 ± 0.6, 0.5 Hz: 0.89 ± 0.4, 1 Hz: 0.42 ± 0.2) for all three perturbation frequencies (p < 0.006 post Bonferroni correction). For the TBI group, the PPT for 1 Hz perturbations showed significant correlation with the functional measures of balance (BBS: r = -0.66, p = 0.037; TUG: r = 0.78, p = 0.008; 5MWT: r = 0.67, p = 0.034, 10MWT: r = 0.76, p = 0.012). These findings demonstrate that individuals with TBI have diminished sensory acuity during standing which may be linked to impaired balance function after TBI.

Keywords: balance; posturography; rehabilitation; sensory threshold detection; traumatic brain injury.