Comparing auditory steady-state responses amplitude evoked by simultaneous air- and bone-conducted stimulation in newborns.

OBJECTIVE: The aim of this study was to evaluate the potential interactions of the simultaneous presentation of air- and bone-conducted stimuli on auditory steady-state responses (ASSR) amplitude in newborns. DESIGN: Bone- and air-conducted stimuli were sinusoidal carrier tones of 500 and 2000 Hz respectively modulated in amplitude (95% depth). Air- and bone- conducted stimuli were either simultaneously recorded in the same ear using insert earphones and bone vibrator respectively, or recorded individually (single stimulation). STUDY SAMPLE: Sixty-nine well babies (135 ears) with ages ranging from 1 to 16 days (mean of 9.2 ± 7.9 days) were tested in this study. RESULTS: No significant changes in ASSR amplitude by air-conducted stimuli were observed when evoked by simultaneous or single stimulation. The same trend prevailed for ASSR amplitudes evoked by bone-conducted stimuli. CONCLUSIONS: The results of this study suggest that the simultaneous stimulation of air-and bone-conducted stimuli does not alter ASSR amplitude values in well babies. Therefore, the results support the use of this technique as a potential hearing screening tool to discriminate between conductive and sensorineural hearing loss.

Distribución biológica de un extracto neuroactivo obtenido de la anémona Bunodosoma granulífera / Biological distribution of neuroactive extract obtained bunodosoma granulifera anemone

Se estudió la distribución biológica del extracto ácido acético-acetónico de Bunodosoma granulífera. Se analizó la afectación de la biodistribución de los polipéptidos radioiodados en función de la pureza radioquímica, la dosis y el tiempo, previa inyección i.p. en ratones. La detección de radioactividad en el cerebro, a partir de los 5 min de inyectado el animal, permite suponer la posible acción del veneno en el sistema nervioso central.