Neurological Disorder Assessment

H. M. Rao, et al., “Predicting cognitive load and operational performance in a simulated marksmanship task,” Frontiers in Human Neuroscience, vol. 14, pp. 1–10, 2020. Publisher's VersionAbstract
Modern operational environments can place significant demands on a service member's cognitive resources, increasing the risk of errors or mishaps due to overburden. The ability to monitor cognitive burden and associated performance within operational environments is critical to improving mission readiness. As a key step toward a field-ready system, we developed a simulated marksmanship scenario with an embedded working memory task in an immersive virtual reality environment. As participants performed the marksmanship task, they were instructed to remember numbered targets and recall the sequence of those targets at the end of the trial. Low and high cognitive load conditions were defined as the recall of three- and six-digit strings, respectively. Physiological and behavioral signals recorded included speech, heart rate, breathing rate, and body movement. These features were input into a random forest classifier that significantly discriminated between the low- and high-cognitive load conditions (AUC = 0.94). Behavioral features of gait were the most informative, followed by features of speech. We also showed the capability to predict performance on the digit recall (AUC = 0.71) and marksmanship (AUC = 0.58) tasks. The experimental framework can be leveraged in future studies to quantify the interaction of other types of stressors and their impact on operational cognitive and physical performance.
J. A. Whitfield, Z. Kriegel, A. M. Fullenkamp, and D. D. Mehta, “Effects of concurrent manual task performance on connected speech acoustics in individuals with Parkinson disease,” Journal of Speech, Language, and Hearing Research, vol. 62, no. 7, pp. 2099–2117, 2019. Publisher's VersionAbstract
Purpose: Prior investigations suggest that simultaneous
performance of more than 1 motor-oriented task may
exacerbate speech motor deficits in individuals with
Parkinson disease (PD). The purpose of the current
investigation was to examine the extent to which
performing a low-demand manual task affected the
connected speech in individuals with and without PD.
Method: Individuals with PD and neurologically healthy
controls performed speech tasks (reading and
extemporaneous speech tasks) and an oscillatory
manual task (a counterclockwise circle-drawing
task) in isolation (single-task condition) and concurrently
(dual-task condition).
Results: Relative to speech task performance, no changes
in speech acoustics were observed for either group when
the low-demand motor task was performed with the
concurrent reading tasks. Speakers with PD exhibited
a significant decrease in pause duration between the
single-task (speech only) and dual-task conditions
for the extemporaneous speech task, whereas control
participants did not exhibit changes in any speech
production variable between the single- and dual-task
Conclusions: Overall, there were little to no changes in
speech production when a low-demand oscillatory motor
task was performed with concurrent reading. For the
extemporaneous task, however, individuals with PD
exhibited significant changes when the speech and manual
tasks were performed concurrently, a pattern that was
not observed for control speakers.
Supplemental Material:
J. A. Whitfield and D. D. Mehta, “Examination of clear speech in Parkinson disease using passage-level vowel space metrics,” Journal of Speech, Language, and Hearing Research, vol. 62, no. 7, pp. 2082–2098, 2019. Publisher's VersionAbstract
Purpose: The purpose of the current study was to characterize
clear speech production for speakers with and without
Parkinson disease (PD) using several measures of working
vowel space computed from frequently sampled formant
Method: The 1st 2 formant frequencies were tracked for
a reading passage that was produced using habitual and
clear speaking styles by 15 speakers with PD and 15 healthy
control speakers. Vowel space metrics were calculated
from the distribution of frequently sampled formant frequency
tracks, including vowel space hull area, articulatory–acoustic
vowel space, and multiple vowel space density (VSD)
measures based on different percentile contours of the
formant density distribution.
Results: Both speaker groups exhibited significant
increases in the articulatory–acoustic vowel space and
VSD10, the area of the outermost (10th percentile)
contour of the formant density distribution, from habitual
to clear styles. These clarity-related vowel space increases
were significantly smaller for speakers with PD than
controls. Both groups also exhibited a significant increase
in vowel space hull area; however, this metric was not
sensitive to differences in the clear speech response
between groups. Relative to healthy controls, speakers
with PD exhibited a significantly smaller VSD90, the area
of the most central (90th percentile), densely populated
region of the formant space.
Conclusions: Using vowel space metrics calculated from
formant traces of the reading passage, the current work
suggests that speakers with PD do indeed reach the more
peripheral regions of the vowel space during connected
speech but spend a larger percentage of the time in more
central regions of formant space than healthy speakers.
Additionally, working vowel space metrics based on the
distribution of formant data suggested that speakers with
PD exhibited less of a clarity-related increase in formant
space than controls, a trend that was not observed for
perimeter-based measures of vowel space area.
T. F. Quatieri, et al., “Multimodal biomarkers to discriminate cognitive state,” in The Role of Technology in Clinical Neuropsychology, R. L. Kane and T. D. Parson, Ed. Oxford University Press, 2017, pp. 409–443.
J. R. Williamson, T. F. Quatieri, B. S. Helfer, G. Ciccarelli, and D. D. Mehta, “Segment-dependent dynamics in predicting Parkinson’s disease,” Proceedings of InterSpeech, pp. 518-522, 2015. Paper
T. F. Quatieri, et al., “Vocal biomarkers to discriminate cognitive load in a working memory task,” Proceedings of InterSpeech, pp. 2684-2688, 2015. Paper
J. R. Williamson, T. F. Quatieri, B. S. Helfer, G. Ciccarelli, and D. D. Mehta, “Vocal and facial biomarkers of depression based on motor incoordination and timing,” Proceedings of the Fourth International Audio/Visual Emotion Challenge (AVEC 2014), 22nd ACM International Conference on Multimedia, pp. 65-72, 2014. Paper
J. R. Williamson, T. F. Quatieri, B. S. Helfer, R. L. HORWITZ, B. Yu, and D. D. Mehta, “Vocal and facial biomarkers of depression based on motor incoordination,” Third International Audio/Visual Emotion Challenge (AVEC 2013), 21st ACM International Conference on Multimedia. pp. 1-4, 2013. Paper