Yi-Shin Chang1, Mathilde Gratiot1, Julia Owen1, Anne Brandes-Aitken1, Shivani Desai1, Susanna Hill1, Anne Arnett1, Julia Harris1, Elysa Marco1, and Pratik Mukherjee1
1University of California in San Francisco, San Francisco, CA, United States
Synopsis
Sensory
processing disorders (SPD) affect 5-16% of school-aged children, and can cause
downstream deficits of intellectual and social development. In this study, we
use diffusion tensor imaging to study a cohort of 41 children with SPD and 41
typically developing children ages 8-12. We confirm and generalize results from
our prior pilot study indicating disrupted posterior white matter in SPD, and
further demonstrate a relationship between direct measurements of tactile and
non-linguistic auditory function and white matter microstructure -- not just
in SPD, but also in typically developing children. Introduction
Sensory
processing disorders (SPD) affect 5-16% of school-aged children, and can cause
downstream deficits of intellectual and social development. While sensory
processing differences are now widely recognized in children with autism,
children with sensory deficits who do not meet autism criteria for language and
social deficits remain virtually unstudied. In a previous, small-scale
diffusion tensor imaging (DTI) study, we demonstrated that children with SPD
have altered white matter microstructure primarily affecting the posterior
cerebral tracts, which subserve basic sensory processing and integration. This altered microstructural integrity was
further shown to correlate with parent report measures of atypical sensory
processing [1]. In this present study, we seek to investigate
prior findings in a larger, mixed-gender cohort, and to further explore
auditory and tactile processing in depth.
Methods
Whole-brain
diffusion tensor imaging (DTI) with 64 directions and b=2000 s/mm2
were acquired in 41 children with SPD (33M/8F), and 41 typically developing
children (TDC) (28M/13F), all aged 8-12 years and matched for IQ and
handedness. Maps of fractional anisotropy (FA), mean diffusivity (MD), and
radial diffusivity (RD) were derived for each subject. Each map was then
skeletonized and registered to the same space using tract-based spatial
statistics, allowing for the calculation of voxel-wise statistics along the
white matter skeleton. Group differences were assessed with nonparametric permutation
testing, and corrected for multiple comparisons using threshold-free cluster
enhancement. Sensory correlations with FA along the white matter skeleton were
assessed using the parent report metrics of the Sensory Profile auditory and
tactile scores, along with direct behavioral measurements of auditory and
tactile processing, derived respectively from the Acoustic Index of the Differential
Screening Test for Processing (DSTP) and the Graphesthesia subtest of the
Sensory Integration Praxis Tests. In post-hoc analyses, general linear models
were constructed to assess the effects of group (TDC vs SPD), age, and gender
for each of these sensory correlations.
Results
As
in our prior work, significant posteriorly biased decreases of FA, and
elevations of MD and RD, were found in the SPD cohort relative to TDC (Figure
1). There were robust correlations of FA with both parent report and direct
measurements of tactile and auditory processing. However, for the parent report
metrics, these correlations were heavily driven by group differences (TDC vs
SPD), and regression lines of the metrics vs FA differed between TDC and SPD
(Figure 2). In contrast, the DSTP and Graphesthesia correlations were most
strongly driven by FA, with TDC and SPD mapping along similar regression lines
(Figure 3). These results suggest that direct measurements of sensory
processing map more closely to the underlying biology, as revealed by DTI, than
their corresponding subjective report metrics.
Conclusions
To
our knowledge, this work is the first to demonstrate a relationship between
direct measurements of tactile and non-linguistic auditory function with white
matter microstructural integrity -- not just in SPD, but also in typically
developing children. We also confirm our
prior DTI results demonstrating altered white matter microstructure in children
with SPD in a larger mixed-gender cohort.
Acknowledgements
No acknowledgement found.References
1. Owen
JP, Marco, EJ, Desai S, et al. Abnormal white matter microstructure in children
with sensory processing disorders. Neuroimage:
Clinical. 2013; 2: 844-853.