Audiology

The clinical application of hearing prediction methods by means of acoustic reflex in hearing screening programs of children

Farnoush Jarollahi

Background: hearing loss is a major health care problem that tends to retard the developmental milestones of children. It takes early detection and intervention to avoid a permanent loss in acquisition of speech and cognitive functions. Hence, the importance of hearing screening in all children especially in the developing world for accurate statistics and early intervention is clear. This work was aimed at predicting hearing in children by means of acoustic reflex measurements
Method: In this study which was performed in 1995, 146 ears(86 children aged between 5-10years old referring to audio logy clinic in Tehran university of medical sciences between august 1995 and February 1996) were evaluated (amongst 95 were normal and 51 ears with SNHL<84dB).the methods Niemeyer and Destrehan formula ,Lilly2 equation, un weighed Sensitivity prediction by acoustic reflex, weighed sensitivity prediction by acoustic reflex to establish their clinical viability.
Results: findings demonstrated that weighed sensitivity prediction by acoustic reflex(WASPAR) have a good correlation with conventional audiometric evaluation(K=.78) and also it has good sensitivity, Specificity , Negative predicted value(NPA) and positive predicted value (PPV).
Conclusion: In case that conventional audiometry is not applicable, WASPAR is a good objective choice in lieu of subjective tests.

Acoustic neurinoma with bilateral audio logical complication a case report

Saeed Farahani

Many of the CP angle tumors are acoustic neuroma, vestibular schowanoma or 8^th nerve tumor. This kind of tumor is benign histologically. Big size ones can cause neurological symptoms such as cerebellar imbalance, edema and cranial nerves dysfunction. Acoustic neuroma is mostly unilateral and audio logical findings manifest a unilateral hearing loss. Although big size tumors can lead to bilateral audio logical symptoms which can affect the findings of hearing assessment. Here, a 31 year-old patient suffering right ear vestibular schowanoma have been reported. changes in left ear pure tone results, acoustic reflex measurements and ABR in addition to hearing loss in the right ear have been demonstrated.

Horizontal canal Benign positional vertigo

Mohtaram Najafi

Benign paroxysmal positional vertigo (BPPV) is a syndrome characterized by transient episodes of vertigo in association with rapid changes in head position in Dix-Halpike Maneuver. This kind of vertigo is thought to be caused by migration of otoconial debris into canals other than the posterior canal, such as the anterior or lateral canals. It is also theoretically possible for many aberrant patterns of BPPV to occur from an interaction of debris in several canals, location of debris within the canal, and central adaptation patterns to lesions.he symptoms of BPPV are much more consistent with free-moving densities (canaliths) in the posterior SCC rather than fixed densities attached to the cupula. While the head is upright, the particles sit in the PSC at the most gravity-dependent position. The best method to induce and see vertigo and nystagmus in BPPV of the lateral semicircular canal is to rotate head 90°while patient is in the supine position, nystagmus would appear in the unaffected side weaker but longer than the affected side. canal paresis has been described in one third of the patients with BPPV. Adaptation which is one of the remarkable features of BPPV in PSC is rarely seen in LSC. Rotations of 270° or 360° around the yaw axis (the so-called barbecue maneuver) toward the unaffected ear are popular methods for the treatment of geotropic HC-BPPV. These maneuvers consist of sequential head turning of 90° toward the healthy side while supine. With these maneuvers, the free-floating otoconial debris migrates in the ampullofugal direction, finally entering the utricle through the nonampullated end of the horizontal canal. This kind of vertigo recovers spontaneously more rapidly and suddenly.

study the effect of Masking on the latency of Auditory Brain stem responses(ABR)

Bahram Jalaei

Masking is a necessary part in ABR test the same as other Audiological experiments to obtain the real responses without the intrusion of the other ear. In the current research we are aimed at studying the effect of the masking noise on the pure latency of wave V and interwave latencies of I-III, III-V and I-V. Noise was delivered to the non test ear with intensities of 0, 30, 50 and 70 dB in four different sessions while the intensity level of the stimulus was fixed in all four sessions.

A new theory of hearing

Nematollah Rouh bakhsh

Recent studies have demonstrated that outer hair cells play two functional roles in the ear: one is the sensory function and the other is motor one. The function of OHCs in being trigered with very poor signals can not be overlooked. This mechanism would lead in improving the sensitivity of the ear. As stimulus intensity increases, little by little, OHC will reach its saturation level and finally the amplification effect decreases.Otoacoustic emissions could be reverberations produced by the responses of outer hair cells .Any decrease in the number of OHCs can cause a mechanical split in the fine tuning mechanism of the organ of corti and result in hearing loss.

Study the Grammatical and lingual skills in hard of hearing children in the schools for the deaf in Tehran

Elaheh Shariat Razavi

A concise Description of Non-linguistic features (Such as Familial, educational and Health information) and linguistic skills in hard of hearing children will be helpful in compensating for their disabilities. In the current study we studied 75 school-Children with average hearing Thresholds of 55-70dB in better ear. All the subjects aged between 8-16years-old with the average age of 11.04.We studied 27 non-linguistic variables by using questionnaire and 32 grammatical variables by studying evoked speech in the participants. The average utterance length of the subjects was estimated 2.763 words. 29% of the all participants' utterances was accurate and just 16.3% of the verbs were produced accurately.One of the most common errors in sentence and verb level, was the mistaken ably omitting of the structural features, the tense problem of the verb and also the mismatching between subject and verb. We also observed a significant correlation between some non-linguistic features such as grade, previous education in conventional schools and the rate of hearing aid usage and the number of accurate utterances in participants.