Electrophysiological Evidence of Early Cortical Sensitivity to Human Conspecific Mimic Voice as a Distinct Category of Natural Sound.

Purpose From an anthropological perspective of hominin communication, the human auditory system likely evolved to enable special sensitivity to sounds produced by the vocal tracts of human conspecifics whether attended or passively heard. While numerous electrophysiological studies have used stereotypical human-produced verbal (speech voice and singing voice) and nonverbal vocalizations to identify human voice-sensitive responses, controversy remains as to when (and where) processing of acoustic signal attributes characteristic of "human voiceness" per se initiate in the brain. Method To explore this, we used animal vocalizations and human-mimicked versions of those calls ("mimic voice") to examine late auditory evoked potential responses in humans. Results Here, we revealed an N1b component (96-120 ms poststimulus) during a nonattending listening condition showing significantly greater magnitude in response to mimics, beginning as early as primary auditory cortices, preceding the time window reported in previous studies that revealed species-specific vocalization processing initiating in the range of 147-219 ms. During a sound discrimination task, a P600 (500-700 ms poststimulus) component showed specificity for accurate discrimination of human mimic voice. Distinct acoustic signal attributes and features of the stimuli were used in a classifier model, which could distinguish most human from animal voice comparably to behavioral data-though none of these single features could adequately distinguish human voiceness. Conclusions These results provide novel ideas for algorithms used in neuromimetic hearing aids, as well as direct electrophysiological support for a neurocognitive model of natural sound processing that informs both neurodevelopmental and anthropological models regarding the establishment of auditory communication systems in humans. Supplemental Material https://doi.org/10.23641/asha.12903839.

Establishing content validity and fidelity of a novel paediatric intussusception air enema reduction simulator.

BACKGROUND: Intussusception is a common, potentially life-threatening paediatric condition. Non-operative treatment with an air enema has been established as the clinical gold standard. There is no validated model for the training of this procedure. Our aim was to produce a novel air enema reduction simulator and validate its use as a training tool. METHODS: A low-cost paediatric intussusception air enema simulator was created. It was designed to include essential key clinical procedural steps. Participants included both procedural experts and novices from the Departments of Paediatric Radiology and Surgery. The simulator was assessed for face and content validity and its physical, conceptual and experiential fidelity by a structured questionnaire using a 5-point Likert's scale. Statistical analysis included a t-test, and a P-value of <0.05 was considered significant. RESULTS: Twenty-four clinicians completed the simulation activity (expert: 13 and novices: 11). All experts had performed a minimum of 40 clinical procedures, and 46% had performed >50 procedures. All scores were favourable in all domains for face and content validity: 3.5 (physical appearance), 3.3 (insertion of the tube and taping), 3.1 (holding of the buttocks) and 3.5 (performing the air enema). The simulator also scored highly with fidelity assessment; visual 3.5, conceptual 3.4. There was no difference in procedural confidence with experts (3.8 versus 3.6, P = 0.28), but there was for novices (1.0 versus 2.9, P = 0.0002). CONCLUSIONS: This low-cost air enema reduction simulator for intussusception has an excellent educational potential for use in a training program in a tertiary centre, as well as, resource-constrained environments.