No abstract

Military and civilian experience has shown that longduration assignments present increased risk of performance failures as the mission progresses. This is due to interruption of normal sleep cycles and psychological pressures of the work environment. There continues to be a need for a non-intrusive fatigue assessment system to successfully monitor the level of alertness of personnel during critical missions and activities. Experimental results on human voice show that specific phones have a predictable dependence on fatigue. Hence, precise phonetic identification and alignment are important to voice-based fatigue detection. This paper explores techniques for detecting fatigue from voice using speech recognition to obtain phonetic alignments. A confidence measure was used to filter out less likely word hypotheses from the ASR's output. In this paper we restricted our analysis to dealing with out-of-vocabulary words. The results obtained from voice show strong correlation with other standardized tests such as Sleep Onset Latency and Sleep, Activity, Fatigue, and Task Effectiveness.

In the present article, we present a means to remotely and transparently estimate an individual's level of fatigue by quantifying changes in his or her voice characteristics. Using Voice analysis to estimate fatigue is unique from established cognitive measures in a number of ways: (1) speaking is a natural activity requiring no initial training or learning curve, (2) voice recording is a unobtrusive operation allowing the speakers to go about their normal work activities, (3) using telecommunication infrastructure (radio, telephone, etc.) a diffuse set of remote populations can be monitored at a central location, and (4) often, previously recorded voice data are available for post hoc analysis. By quantifying changes in the mathematical coefficients that describe the human speech production process, we were able to demonstrate that for speech sounds requiring a large average air flow, a speaker's voice changes in synchrony with both direct measures of fatigue and with changes predicted by the length of time awake.

13 of 17 cats which received unilateral olfactory tubercle lesions exhibited contralateral sensory inattention and ipsilateral circling and hyperresponsiveness. The possible neural substrates involved in these asymmetries are discussed, including ascending amine systems and ascending and descending connections with the orbital cortex.

We have observed that midsagittal reticular formation lesions in cats produce bilateral deficits in attention to and localization of various sensory modalities. To correlate these changes with previously reported changes following lesions in other areas of the brain, we propose the existence of two interdependent inhibitory pathways which originate in the frontal lobes.