  Recommendations for common outcome measures following pediatric traumatic
brain injury (TBI) support the integration of instrumental measurements
alongside perceptual assessment in recovery and treatment plans. A
comprehensive set of sensitive, robust and non-invasive measurements is
therefore essential in assessing variations in speech characteristics over time
following pediatric TBI. In this article, we study the changes in the acoustic
speech patterns of a pediatric cohort of ten subjects diagnosed with severe
TBI. We extract a diverse set of both well-known and novel acoustic features
from child speech recorded throughout the year after the child produced
intelligible words. These features are analyzed individually and by speech
subsystem, within-subject and across the cohort. As a group, older children
exhibit highly significant (p<0.01) increases in pitch variation and phoneme
diversity, shortened pause length, and steadying articulation rate variability.
Younger children exhibit similar steadied rate variability alongside an
increase in formant-based articulation complexity. Correlation analysis of the
feature set with age and comparisons to normative developmental data confirm
that age at injury plays a significant role in framing the recovery trajectory.
Nearly all speech features significantly change (p<0.05) for the cohort as a
whole, confirming that acoustic measures supplementing perceptual assessment
are needed to identify efficacious treatment targets for speech therapy
following TBI.
