Orozimbo Alves Costa Filho

PubMed2005

[Electrophysiological study of the central and peripheral hearing system of aphasic individuals].

SUBJECT: Electrophysiology of the auditory system. OBJECTIVE: Electrophysiological evaluation of the peripheral and central auditory system of brain injured patients. METHOD: Experimental group: eleven brain injured and aphasic subjects, both genders and with ages ranging from 43 to 75; control group: eleven individuals without hearing complaints, equalized as to gender and age. The subjects were evaluated through auditory brainstem response (ABR); auditory middle latency response (AMLR) and auditory P300 response. RESULTS: An increase in the V wave latency and I-V interpeak in both groups, due to the age factor. The presence of statistically significant hemispheric differences when compared to the Pa component in MLAEP research, registered in the C3 (left hemisphere) and the C4 (right hemisphere). In researching the P300 Cognitive Potential, there was an absence or increase in P300 latency and a decrease in P300 amplitude in the presence of the N2 component. CONCLUSION: The AMLR and auditory P300 response have proven to be effective instruments for evaluating aphasic individuals.

Adult↗

PubMedDate not supplied

[Bone conduction auditory brainstem responses in normal hearing individuals].

BACKGROUND: bone conduction auditory brainstem responses (ABR) in normal hearing individuals. AIM: to evaluate the clinical applicability of bone conduction ABR, characterizing normality and determining an assessment protocol. METHOD: participants of this study were 22 individuals with normal hearing (20dB NA), with ages between 20 and 30 years, 14 female and 8 male. All individuals were assessed using air and bone (vibrator positioned on the forehead and mastoid) conduction ABR. EP25 equipment, Interacoustic; 3A insertion phone; B-71 bone vibrator; click stimulus. RESULTS: it was possible to evaluate the bone conduction ABR in all individuals. The results demonstrate that the electrophysiological threshold obtained when the vibrator was positioned on the forehead (32.69+/-5.63 and 32.5+/-7.07dB nHL) was higher than that obtained when the vibrator was positioned on the mastoid (25.00+/-7.33 and 30.00+/-5.34dB nHL) for both genders respectively. For this reason the vibrator was positioned on the mastoid. The electrophysiological threshold obtained by bone conduction was higher than that obtained by air conduction for both genders and also when all individuals were grouped together. Thus it is necessary to use a correction factor, according to the results, of 10dB nHL. The latency-intensity values of the V wave in the ipsilateral and contralateral recordings differed statistically according to gender, and should be considered separately. The value of 26.81+/-6.99dB nHL was adopted as being the normal threshold for bone conduction ABR. CONCLUSION: it is possible to evaluate bone conduction ABR in the clinical environment. These results, when considered along with the air conduction ABR, increase the chances of a more precise diagnosis regarding the type of hearing loss.

Adult↗