Responsible Center: NSBRI
Grant Monitor:
Center Contact:
Unique ID: 4319
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Solicitation / Funding Source: 2003 Biomedical Research & Countermeasures 03-OBPR-04
Grant/Contract No.: NCC 9-58-NBPF00406
Project Type: GROUND
Flight Program:
TechPort: No |
No. of Post Docs: 0
No. of PhD Candidates: 1
No. of Master's Candidates: 0
No. of Bachelor's Candidates: 6
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No. of PhD Degrees: 0
No. of Master's Degrees: 0
No. of Bachelor's Degrees: 2
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Human Research Program Gaps: |
(1) BMed-101:We need to identify, quantify, and validate the key selection factors for astronaut cognitive and behavioral strengths (e.g., resiliency) and operationally-relevant performance threats for increasingly Earth independent, long-duration, autonomous, and/or long-distance exploration missions. (2) BMed-103:What are the validated, efficacious treatments (individual or Team-based) and/or countermeasures to prevent adverse behavioral conditions, CNS/neurological, and/or psychiatric disorders caused by either single and/or integrated exposures to spaceflight hazards during exploration class missions? (3) BMed-108:Given each crewmember will experience multiple spaceflight hazards simultaneously, we need to identify and characterize the potential additive, antagonistic, or synergistic impacts of multiple stressors (e.g., space radiation, altered gravity, isolation, altered immune, altered sleep) on crew health and/or CNS/ cognitive functioning to develop threshold limits and validate countermeasures for any identified adverse crew health and/or operationally-relevant performance outcomes.
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Task Description: |
Radiation in space or on the moon can result in brain damage that degrades an astronaut's ability to perform cognitive tasks, particularly ones involving changing the course of one's actions. Shifts in personality can also occur. Task demands, sleep deprivation and psychosocial stressors can also degrade cognitive performance. Our goal was a speech monitoring system suitable for space-flight that would detect degraded cognitive ability and stress by means of automatic, ongoing acoustic analysis of an astronaut's speech. The system would provide astronauts and ground-control with timely warnings before profound disability occurs, and provide ongoing assessment of ability to perform. No additional sensors attached to individuals or tasks would be involved; it would be impossible to evade the voice monitoring system. Moreover, our voice analysis techniques preserve confidentiality because the relevant acoustic measures reflect impaired speech motor control rather than message content.
Our procedures are based on recent insight on how brains work. Complex behaviors such as walking, talking, comprehending the meaning of a sentence, or deciding what you should do when circumstance change, involve linked activity in different parts of the brain. The subcortical basal ganglia are structures of the brain that support "circuits" (akin to electrical pathways) connecting different regions of the brain. Independent studies show that circuits involving the basal ganglia regulate motor control, cognition, emotional responses and some aspects of a person's personality. Damage to the basal ganglia, which are sensitive to both radiation and oxygen deprivation (hypoxia), thus can degrade these aspects of behavior. We have confirmed that acoustic measures quantifying slow speech motor control can be used to monitor cognitive impairment induced by hypoxic and cosmic-ray induced insult to the brain, as well as degraded cognitive performance resulting from task difficulty, other stressors and sleep deprivation. Other acoustic metrics can identify sleep deprivation and stress derived from perceived poor performance. We were moving towards an operational system and developed a prototype computer algorithm that automatically measures speech rates in low noise environments.
Our project had two complementary components. 1- Our Everest Space-Analog studies provide the foundation for an operational system that uses acoustic measures of a person's speech to detect cognitive deficits resulting from exposure to radiation in space or on the moon, as well as hypoxia in spacewalks. 2- Our cooperative laboratory study with the NSBRI project directed by Dr. David Dinges at the Medical School of the University of Pennsylvania has yielded a procedure that uses these acoustic measures and additional ones to detect impaired cognitive performance resulting from the stress of task difficulty, as well as psychosocial stressors and sleep deprivation. We developed prototype computer algorithms that automatically derive relevant acoustic measures from running speech.
Everest Space-Analog.
Independent NSBRI research confirms that the basal ganglia are sensitive to radiation; they also are susceptible to oxygen deprivation (hypoxic insult) in climbers breathing thin air at extreme altitudes. Thus we can use climbers ascending Everest as models for the some of the effects of radiation on crews in space. The research is ethical because subjects willfully expose themselves to the dangers of climbing Everest. Climbing Everest entails ascending to a series of high camps. At each camp with progressively lower oxygen, our climber-subjects perform sentence comprehension tests, the Wisconsin Card Sorting Test (WCST), and mental arithmetic tests that simulate operational tasks encountered in spaceflight. WCST performance translates to the ability to change plans when circumstances change. At higher altitudes, error rates on the WCST and arithmetic tests tend to increase and it takes longer to comprehend the meanings of sentences. We have used the BLISS interactive speech analysis computer algorithms developed at Brown University to derive acoustic speech measures that reflect slower motor control. These acoustic metrics track cognitive dysfunction. Our procedures detects lower sentence comprehension or degraded WCST performance 91% of the time. A system that used measures of speech rate to monitor these cognitive deficits would have had a 3% miss rate and 6% "false alarm" rate (decisions that do not reflect with impairment).
Task difficulty, stress and sleep deprivation.
In the Dinges laboratory setting subjects had to perform easy and difficult mental arithmetic tasks. Subjects also performed these tasks after sleep deprivation and with a psychosocial stressor (being informed that their performance was deficient). Measures of slower speech tracked higher error rates and fewer solutions as they performed the more difficult task. Acoustic measures that reflect laryngeal activity identified those subjects who were sleep deprived or subjected to the psychosocial stressor.
Earthbound applications.
Our objective acoustic analyses provide direction for focused intervention for children having verbal apraxia (speech motor sequencing difficulties). Our procedures have been used to evaluate new procedures for the treatment of Parkinson's disease, which involves basal ganglia degeneration. The effects of task difficulty, sleep deprivation and other stressors could be voice monitored in applications ranging from enhancing computer-implemented instruction to safely driving a truck. |
Research Impact/Earth Benefits: |
The techniques we developed for unobtrusively monitoring cognitive status and stress via automated measurement of speech parameters have applications in general aviation. Systems based on these techniques could be used to monitor air crews for gradual effects of partial or slow failure of aircraft pressurization systems. Hypoxia resulting from such depressurization degrades cognitive function and crew members not only are unable to perform their tasks but fail to notice their own impairment, leading to disaster. Speech-based systems could monitor both motor and cognitive dysfunction resulting from stress and sleep deprivation in occupations ranging from air traffic controllers to truck drivers. Measures of vowel and pause durations could be used to pace computer-aided instruction, adjusting the presentation of information to an individual's cognitive ability.
Our project's techniques have already been used to assess the efficacy of new surgical procedures for the treatment of Parkinson's disease. They may also provide instruments that can detect memory loss in the early stages of Alzheimer's disease. Such early detection would permit clinicians to take maximal advantage of therapies that can delay or even arrest further decline. Our techniques may have application to the diagnosis, assessment, and treatment of other human pathologies stemming from impaired basal ganglia function in neural circuits regulating speech production, cognition and personality. These include not only neurodegenerative diseases but also the results of acute insult. For example, hypoxia during birth can lead to verbal apraxia in children - a syndrome where speech motor and orofacial motor control is degraded and which can result in cognitive and linguistic deficits. Our computer-implemented speech analysis techniques identify specific deficits that are not evident by listening to the children; therapy can then be directed towards the remediation of these problems. We also can identify the specific cognitive deficits accompanying many instances of verbal apraxia, again directing treatment. Our research can be useful in identifying genetic and environmental factors underlying the condition. We are extending this line of enquiry to autism, working with specialists in pediatric neurology.
Another potential application is in assessing the truthfulness of verbal statements. Dissimulation generally involves greater cognitive effort, activating more brain structures that would be the case for truthful statements. This yields slower speech which we can readily detect. |