Altered GABA Concentration in Brain Motor Area Is Associated with the Severity of Motor Disabilities in Individuals with Autism Spectrum Disorder

Yumi Umesawa,Reiko Fukatsu,Masakazu Ide,Toshihiro Kato,Kanae Matsushima,Takeshi Atsumi,Makoto Wada

doi:10.1007/s10803-020-04382-x

Abstract

Several motor disabilities accompanied with autism spectrum disorder (ASD) are widely known despite limited reports of underlying neural mechanisms. Gamma-aminobutyric acid (GABA) levels in the motor-related cortical areas modulate several motor performances in healthy participants. We hypothesized that abnormal GABA concentrations in the primary motor area (M1) and supplementary motor area (SMA) associate with different motor difficulties for ASD adolescents/adults. We found that increased GABA concentrations in M1 measured using 1H-magnetic resonance spectroscopy exhibited lower motor performance in tasks requiring increased muscle strength while lower GABA concentrations in SMA were associated with lower scores in tests measuring body coordination. The degrees of neural inhibition in the M1 and SMA regions would contribute to different dimensions of motor disabilities in autism.

Highlights

These motor disabilities in individuals with autism spectrum disorder (ASD) represented by Developmental Coordination Disorder (DCD) includes several aspects that appear in daily life
We confirmed that each of the fit errors for the gamma-aminobutyric acid (GABA)+ measurements in both regions of interest (ROIs) was below 20%, a criterion used in previous reports as the acceptance level to obtain reliable MRS measurements (Brix et al 2015; Harada et al 2011), the averaged fitting error in the ASD group was significantly greater than that in the typically developing (TD) group only in supplementary motor area (SMA) ROI (t (38) = 3.1, p = 0.003, d = 1.00, 95% CI [0.008, 0.037]; Table 3)
Previous studies have reported that decreased GABA+ concentrations in M1 result in better motor performance in neurotypical participants (Cogiamanian et al 2007; Stagg et al 2011; Tanaka et al 2009)

Summary

Introduction

These motor disabilities in individuals with ASD represented by DCD includes several aspects that appear in daily life. To reveal the neural basis of motor impairments in individuals with ASD, especially for characteristics studied using clinical assessments that evaluate several aspects of DCD, we examined types of motor skills associated with lower/higher GABA+ concentrations in brain motor areas. For this objective, we applied a clinical assessment tool which is used to evaluate both of fine and gross motor skills, the Bruininks-Oseretsky Test of Motor Proficiency, second edition (BOT-2, Pearson, San Antonio, USA; for more details, see the method section). The intellectual quotients (IQs) were assessed using the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III)

Objectives

Methods

Results

Conclusion