Exploring the Differences Between an Immature and a Mature Human Auditory System Through Auditory Late Responses in Quiet and in Noise.

Children are disadvantaged compared to adults when they perceive speech in a noisy environment. Noise reduces their ability to extract and understand auditory information. Auditory-Evoked Late Responses (ALRs) offer insight into how the auditory system can process information in noise. This study investigated how noise, signal-to-noise ratio (SNR), and stimulus type affect ALRs in children and adults. Fifteen participants from each group with normal hearing were studied under various conditions. The findings revealed that both groups experienced delayed latencies and reduced amplitudes in noise but that children had fewer identifiable waves than adults. Babble noise had a significant impact on both groups, limiting the analysis to one condition: the /da/ stimulus at +10 dB SNR for the P1 wave. P1 amplitude was greater in quiet for children compared to adults, with no stimulus effect. Children generally exhibited longer latencies. N1 latency was longer in noise, with larger amplitudes in white noise compared to quiet for both groups. P2 latency was shorter with the verbal stimulus in quiet, with larger amplitudes in children than adults. N2 latency was shorter in quiet, with no amplitude differences between the groups. Overall, noise prolonged latencies and reduced amplitudes. Different noise types had varying impacts, with the eight-talker babble noise causing more disruption. Children's auditory system responded similarly to adults but may be more susceptible to noise. This research emphasizes the need to understand noise's impact on children's auditory development, given their exposure to noisy environments, requiring further exploration of noise parameters in children.

Cognitive structure of executive deficits in frontally lesioned head trauma patients performing activities of daily living.

OBJECTIVE: Executive functions in activities of daily living (ADL) were investigated in 10 patients with frontal lobe lesions after a mild to severe closed head injury (CHI). METHOD: The CHI patients were compared to 12 normal controls with a neuropsychological test battery, a script recitation task and a realistic simulation of complex multitask ADL (planning and preparing a meal). RESULTS: Though the CHI patients were significantly slow on one test and subject to interference on an attention test with parametric testing, the groups did not differ on any neuropsychological test with non parametric testing. However, the CHI patients manifested marked anomalies in the meal preparation task. While small sequences of actions were easily produced, large action sets could not be correctly executed. CONCLUSION: An outstanding deficit in strategic planning and prospective memory appears to be an important underpinning of the impairment of ADL observed in CHI patients with frontal lobe lesions.