Biomedical subjects

T Rahko

Publications and source records attributed to T Rahko.

77 records · Page 5Linked to original sources

PubMedDate not supplied

SISI test and adaptation. II. Subjects with conductive hearing defects.

The effect of adaptation of the ear on the SISI test was studied at 500 Hz and 2000 Hz in 43 patients with chronic otitis and in 20 patients with otosclerosis. The mean adaptation was slightly over 10 dB, except in the otosclerosis group at 2000 Hz, for which the value was nearly 20 dB after continuous stimulation at 20 dB SL for 3 min. The mean SISI values ranged from 15% to 31% in the preadaptation tests and from 9% to 31% in the postadaptation tests. The scatter of the pre-and postadaptation SISI scores was wide, making statistical treatment of the results difficult. In the total material 22% of the values at 2000 Hz were positive according to Jerger's classification, and 32% were questionable. Adaptation slightly reduced the proportion of positive values, but there were changes towards both higher and lower levels in the cases of chronic otitis, while all the otosclerosis changes were diminutions.

Acoustic Stimulation↗

PubMedDate not supplied

SISI test and adaptation. III. Subjects with perceptive hearing defects.

The effect of the adaptation of the ear on the SISI test was studied in 60 completely and 18 incompletely recuriting patients and in 5 patients with a verified acoustic neurinoma at 500 and 2000 Hz. The subjective suprathreshold adaptation to a 3 min tone of 20 dB (SL) ranged from 10 dB to over 20 dB, depending on the frequency and type of defect. The pre-adaptation mean SISI values in the recruiting groups ranged from 38 to 51% and the post-adaptation means from 38 to 49%. In retrocochlear lesions only one SISI value was questionable before and after adaptation, the others being 0%. The dispersion of the SISI scores was considerable, a fact that made statistical treatment difficult. Adaptation did not significantly affect the SISI value. It could be ascertained that high SISI values did not reliably distinguish between the hearing defect types, but if the SISI was low the possibility of a retrocochlear lesion should always be borne in mind.

Acoustic Stimulation↗

PubMedDate not supplied

Sensorineural hearing loss and acute otitis media in children.

Sensorineural hearing of 359 otoscopically and tympanometrically normal 5-year-old children with known otitis-history was studied under ideal conditions. In the subgroups of children with a different number (0, 1-2, 3-7, greater than or equal to 8) of attacks of acute otitis media (AOM) in their history, the mean bone conduction thresholds unregularly varied from 0.1 dB to 7.4 dB, depending on the frequency and the subgroup studied. The proportion of the ears with a bone conduction threshold greater than 10 dB at 0.5, 1, 2 or kHz ranged, also unregularly, from 10.8% to 0.5%, the greatest percentages being found at 0.5 and 1 kHz in the children without a history of AOM. Thus, neither AOM nor its treatment, even if frequently occurring, seem to cause permanent sensorineural hearing loss in children.

Acute Disease↗

PubMedDate not supplied

Simultaneous four-channel electric-response audiometry results in 8 years of hearing evaluation among small children.

The results of 8 years' experience with slow cortical-evoked responses obtained by a four-channel method are reported. The conclusion is that, even in this form, ERA is not a reliable tool for diagnosing hearing defects in children. The time course of the mean ERA threshold of 138 children examined in Turku University for periods ranging from 6 months to over 3 years is presented. The results are discussed. Electrocochleography or brain stem audiometry is recommended for clinical use.

Age Factors↗

PubMedDate not supplied

The pure-tone hearing thresholds of otologically healthy 14-year-old children.

The mean pure-tone air conduction (AC) and bone conduction (BC) hearing thresholds (HT) of 534 randomly selected, caucasian, white, urban children with normal otoscopy, otomicroscopy and impedance audiometry, i.e. normal middle ear function, are presented here. Children with pathological middle ear findings or abnormal impedance audiometry were excluded. The average age was 13.8 years, SD 0.5, at the date of examination. The mean air conduction thresholds varied between 0.6 dB at 1 kHz and 9.9 dB at 6 kHz, and the bone conduction thresholds varied between -1.1 dB at 0.5 kHz and 1.1 dB at 4 kHz. The pure-tone average (PTA) (the average of AC hearing thresholds of 0.5, 1 and 2 kHz) of all ears was 1.5 dB. Ninety to ninety-eight per cent of pure-tone AC hearing thresholds at frequencies of 0.5-4 kHz were between -5 dB and 10 dB. The distributions are presented and compared.

Adolescent↗