Attenuation values for a supra-aural earphone for children and insert earphone for children and adults

Earphone attenuation values were determined for 17 children (6-14 years old) using supra-aural (TDH-49P/Model 51 cushion) and insert earphones (E-A-Rtone 3A) terminated by an E-A-Rlink 3A (for normal size ear canals) or E-A-Rlink 3B (for small size ear canals) foam eartips, and for 10 adults having small ear canals using insert earphones and E-A-Rlink 3B foam eartips. The test signals were 1/3-octave bands of noise presented in a diffuse sound field (re: ANSI S12.6-1984). The supra-aural earphone attenuation values for the children were slightly higher (more attenuation) or similar to reported adult values, and always lower (less attenuation) compared with insert earphone/E-A-Rlink 3A (IE/3A) or 3B (IE/3B) values for both children and adults. The IE/3B attenuation values were similar between the children and adults and provided slightly more attenuation than the IE/3A. Overall, the results indicated that the ANSI S3.1-1991 maximum permissible ambient noise levels allowed in a test room for ears covered testing with a supra-aural earphone, which were determined using adult values, are appropriate for testing children. Future revisions of ANSI S3.1-1991 may include maximum permissible ambient noise levels for testing with insert earphones. The IE/3A and IE/3B attenuation values could be used for that purpose. In the meantime, because more attenuation was provided by the IE/3A and IE/3B, they can be used for testing both children and adults in higher ambient noise levels than specified in ANSI S3.1-1991.

Reference threshold levels for an ER-3A insert earphone

The purpose of this study was to obtain normal hearing thresholds for an ER-3A insert earphone as a contribution for future standardization and for comparison with previous studies and interim ANSI and ISO insert earphone reference equivalent threshold sound pressure levels (RETSPLs). Hearing thresholds were obtained on each ear of 48 normal-hearing subjects from 125 to 8000 Hz using ER-3A and TDH-49P earphones referenced to a Bruel and Kjaer DB-0138 HA-2 and NBS-9A acoustic coupler, respectively. The mean unadjusted and adjusted ER-3A thresholds were in very good agreement with the mean thresholds averaged over eight other studies. Further, the mean adjusted ER-3A thresholds were in very good agreement with the interim ANSI RETSPLs while the mean unadjusted ER-3A thresholds were slightly higher than the ISO RETSPLs. Also, mean ER-3A thresholds averaged over a nine study data base were in closer agreement with the interim ANSI than the ISO RETSPLS. Overall, the interim ANSI insert earphone RETSPLs were recommended for clinical use.

Repeatability of high-frequency thresholds

High-frequency (10, 12, 14, 16, and 18 kHz) thresholds were obtained for each ear of 50 young adults having normal low-frequency hearing across four test sessions separated by at least 1, but no more than 2, weeks using a Beltone 2000 audiometer. The threshold differences between each possible test session comparison (N = 6) were not significantly (p greater than 0.05) different for ear, test session comparison, or frequency. Overall, intrasubject high-frequency thresholds were found to be repeatable and within a clinically acceptable range of +/- 10 dB for at least 94% of the ears, regardless of test session comparison and frequency.

Hearing aid coupler output level variability and coupler correction levels for insert earphones

HA coupler type SPLs were independently determined by two experimenters for five repeated measurements with and without replacement of two ER-3A and two EARTONE 3A insert earphones. Measurements were made using a B&K DB-0138 coupler configured as an HA-1, HA-2 earphone coupler and HA-2 earphone coupler with entrance through a rigid tube referred to as the DB-0138 coupler. The HA-1, HA-2, and DB-0138 SPLs were found to be very stable (+/- 0.2 dB) for all intra- and interexperimenter measurements for each insert earphone and coupler type from 125 to 8000 Hz. Averaged across both experimenters and all repeated measurements, the mean HA-1 and HA-2 coupler SPLs were similar for each insert earphone from 125 to 8000 Hz. The mean HA-1, HA-2, and DB-0138 coupler SPLs were similar for each insert earphone from 125 to 2000 Hz; however, from 3000 to 8000 Hz the DB-0138 coupler SPLs were higher than the HA-1 and HA-2 coupler SPLs for each insert earphone. This occurred because of the geometrical differences between the insert earphone to coupler connections and coupler types. The HA-1 minus DB-0138 and HA-2 minus DB-0138 coupler SPL differences, or coupler correction levels, could be explained by quarter-wave resonances and stepped-diameter tubing systems creating acoustic horn effects.

High-frequency hearing thresholds in young adults using a commercially available audiometer

Test and re-test high-frequency (10-20 kHz) thresholds were obtained for 200 ears of 100 normally hearing (0.25-8 kHz) young adults (18-28 years old) using a Beltone 2000 audiometer and Sennheiser HD 250 earphones referenced to sound pressure levels developed in a Bruel and Kjaer flat-plate coupler. Normative high-frequency thresholds could not be recommended for clinical use due to the very large intersubject threshold variability. This occurred even though test versus re-test thresholds were not significantly different (p greater than 0.05) at any frequency. However, comparisons of the test minus re-test threshold for individual ears were within a clinically acceptable range of +/- 10 dB for at least 95% of the ears at each frequency. Future research should concern intrasubject threshold reliability and variability rather than specifying intersubject normative thresholds.

Attenuation provided by four different audiometric earphone systems

The attenuation provided by TDH earphones in MX-41/AR and P/N 51 cushions, Audiocup earphone enclosures and ER-3A insert earphones with ER3-14 foam earplugs was determined for 30 normally hearing subjects using a real-ear attenuation at threshold paradigm. The MX-41/AR and P/N 51 cushions provided about the same amount of attenuation which was less than the attenuation provided by the Audiocup enclosures. The ER-3A/ER3-14 provided the highest amount of attenuation. The MX-41/AR and ER-3A/ER3-14 attenuation values were in agreement with other studies using similar methodology. However, the attenuation provided by the Audiocup enclosures was considerably less, in the lower frequencies, than reported in two other studies. ANSI S3.1-1977 supra-aural earphone cushion attenuation values, which were determined using pure-tones presented in a free-field, should be replaced by earphone cushion attenuation values determined with 1/3 octave bands of noise presented in a diffuse sound field.

Combined MR imaging and spectroscopy of bone and soft tissue tumors

Twenty-three patients with bone and soft tissue tumors were studied with combined magnetic resonance (MR) imaging and spectroscopy. The MR examinations were utilized to determine the size, internal characteristics, and relationships of the tumor to the surrounding tissues. They also determined the optimal placement of the surface coil. The surface coil profile was the localization technique utilized. Four patients were also studied with one-dimensional chemical shift localization. Tumors were grouped according to histologic type, degree of muscle contamination, size, and extent of necrosis. Quantitative comparison among the groups was carried out by comparing the mean ratios of the low-energy phosphate portion of the spectra [phosphomonoester (PME), Pi, phosphodiester (PDE)] to beta-nucleotide triphosphate (NTP). Tumor spectra typically showed a relative elevation in PME, Pi, and PDE and a relative decrease in phosphocreatinine. No characteristic spectra were observed for individual tumor types. Contamination of the tumor spectra from surrounding muscle impaired interpretation of the spectral data. Tumor size and extent of necrosis were important determinants of the relative degree of abnormally elevated metabolite peaks (PME, Pi, PDE). A trend toward a higher mean PME/beta-NTP ratio was observed among high-grade lesions. Combined MR imaging and spectroscopy is a useful way to study tumor metabolism. Muscle contamination is a significant problem in analysis of the spectra. Better localization techniques are required.

[Antiphlogistic effect of bromelaine following third molar removal]

A placebo-controlled double-blind study of 100 patients with impacted and/or dislocated lower wisdom teeth was conducted to examine the tolerance and antiphlogistic efficacy of bromelaine--a mixture of proteolytic enzymes from ananas comosus. Treatment was started 1 day prior to third molar surgery with a daily dose of 3 x 80 mg and was continued for a total of 6 days. On the 1st day following surgery, linear measurement (distance: tragus-pogonion) showed swelling to be 7.5% lower under drug treatment than in the placebo group. Two-dimensional image evaluation increased this difference to 15.9%, which however still failed to attain the significance level of 20%. Between the 3rd and the 7th postoperative day no differences were found between the two groups regarding the extent of soft tissue swelling or the speed of edema resolution.

Bone conduction threshold levels for different bone vibrator types

This study determined if bone conduction (BC) thresholds were influenced by vibrator type. BC thresholds were obtained for 100 subjects using mastoid placement of Radioear B-71 and B-72 and Pracitronic KH 70 bone vibrators. The nontest ear was masked (30 dB EL) and the ear ipsilateral to the vibrator was open except when testing at 3000 and 4000 Hz when the ear canal was occluded with an earplug to guard against acoustic radiation. BC thresholds at 250 Hz obtained with the B-72 and KH 70 were significantly (p less than .05) higher by 10.5 dB and at 500 Hz were significantly (p less than .05) lower by 5.5 dB than for the B-71. BC thresholds at other frequencies (1000, 2000, 3000, and 4000 Hz) were not significantly different among vibrator types. The findings indicated that reference equivalent threshold force levels (RETFLs) for BC audiometry should be specified by bone vibrator type.

Repeatability of high-frequency bone conduction thresholds

The purpose of this study was to determine the repeatability of high-frequency, bone conduction thresholds and to increase the data base concerning high-frequency, bone conduction threshold levels. Bone conduction thresholds were obtained on 30 subjects having normal, low, and mid frequency (0.25 to 8 kHz) hearing thresholds within and across five test sessions using a Pracitronic KH 70 bone vibrator referenced to a Brüel and Kjaer 4930 mechanical coupler at 1, 4, 8, 10, 12, 14, and 16 kHz. Within and across sessions, the bone conduction thresholds were not significantly (p greater than 0.05) different at each frequency indicating that repeated testing without replacing the bone vibrator (within session) and with replacing the bone vibrator (across session) did not influence the threshold measurements. Clinical implications concerning high-frequency, bone conduction audiometry are discussed.

Accuracy of a 40 dB HL Audioscope and audiometer screening for adults

This study determined the accuracy of an AudioScope (AS) and pure-tone audiometer (PTA) screening at 40 dB HL from 500 to 4000 Hz in reference to a pure-tone threshold (PTT) test on 1210 ears of adult subjects 20 to 96 yr old. The overall results (averaged over age group and frequency) indicated that the AS and PTA screenings were equally accurate in reference to the PTT test. Averaged over the screening tests, the sensitivity was 91.4% with a false negative rate of 8.6% and the specificity was 93.5% with a false positive rate of 6.5%. As a function of age (averaged over frequency), the AS and PTA screenings had similar accuracy and decreased as age increased to about 60 yr old and then remained stable. As a function of frequency (averaged over age), each screening test had similar accuracy for each frequency. It was concluded that the results of a 40 dB HL AS or PTA screening are very accurate in reference to a PTT test.

Random-clone strategy for genomic restriction mapping in yeast

An approach to global restriction mapping is described that is applicable to any complex source DNA. By analyzing a single restriction digest for each member of a redundant set of lambda clones, a data base is constructed that contains fragment-size lists for all the clones. The clones are then grouped into subsets, each member of which is related to at least one other member by a significant overlap. Finally, a tree-searching algorithm seeks restriction maps that are consistent with the fragment-size lists for all the clones in each subset. The feasibility of the approach has been demonstrated by collecting data on 5000 lambda clones containing random 15-kilobase inserts of yeast DNA. It is shown that these data can be analyzed to produce regional maps of the yeast genome, extending in some cases for over 100 kilobases. In combination with hybridization probes to previously cloned genes, these local maps are already useful for defining the physical arrangement of closely linked genes. They may in the future serve as building blocks for the construction of a continuous global map.

Acoustic radiation produced by B-71, B-72, and KH 70 bone vibrators

The amount of acoustic radiation produced by two samples of a Radioear B-71, B-72, and Pracitronic KH 70 bone vibrator was determined for 30 normal-hearing subjects at 4000 Hz. The mean amount of acoustic radiation was very similar for both samples of each vibrator type but significantly (p less than 0.05) different between the bone vibrator types. The mean amount of acoustic radiation averaged over both samples was 8.3 dB for the B-72, 4.3 dB for the B-71, and -0.3 dB for the KH 70. Individual subject data indicated that the B-72 produced excessive acoustic radiation (greater than 5 dB) for 80% of the subjects, the B-71 for 38% of the subjects, and the KH 70 for 8% of the subjects which could cause an invalid high-frequency air-bone gap. Precautions should be taken during bone conduction audiometry to eliminate the possibility of acoustic radiation produced by bone vibrators. A need for additional standards in this area is stressed.

Coupler output level differences resulting from repeated transducer placement

Coupler output levels were obtained for six repeated placements of a TDH-49 earphone in a P/N 51 cushion on a NBS 9A coupler and a B-71 and B-72 bone vibrator on a mechanical coupler from 250 to 4000 Hz using experienced (N = 9) and untrained subjects (N = 9) who were later trained. The largest minus the smallest coupler output levels across the repeated placements were determined for each subject and transducer at each frequency. The coupler output level differences were similar across subject group for each transducer at each frequency and were not reduced by training. The median and mean differences for the TDH-49 were less than 1 dB, consistent across frequency, and the highest range score never exceeded ANSI tolerance levels. The median and mean differences for the B-71 and B-72 were higher than for the TDH-49 but did not exceed ANSI tolerance levels and were frequency dependent corresponding to the high frequency resonance slope of the vibrator. However, for some subjects, the differences exceeded ANSI tolerance levels for both vibrators, especially for the B-72 at 250, 2000, and 4000 Hz.

Influence of temperature on the output of a mechanical coupler

This research determined the influence of temperature on the output of two Bruel and Kjaer 4930 mechanical couplers using a Radioear B-71, B-72, and a Pracitronic KH 70 bone vibrator. When the temperature of the mechanical couplers was varied from 17 degrees C (62.6 degrees F) to 29 degrees C (84.2 degrees F) in steps of 3 degrees C (5.4 degrees F) and the bone vibrators had a constant temperature, the output of each mechanical coupler systematically decreased as its temperature increased for each bone vibrator type. The largest output differences for both couplers and each vibrator occurred at 4000 Hz. The average of these differences across the couplers and vibrators was 6.6 dB higher at 17 degrees C than at 29 degrees C which dB/3.6 degrees F). When the temperature of the bone vibrators was 17 and 29 degrees C and the mechanical couplers were maintained at a constant temperature, there were little or no differences in the output of the mechanical couplers. The temperature of a mechanical coupler rather than that of the bone vibrator is a critical variable in bone conduction calibration. Mechanical coupler temperature-dependent output coefficients were determined for use in bone conduction calibration from 250 to 4000 Hz for all three bone vibrator types and at 6000 and 8000 Hz for the KH 70.

[Venous digital subtraction arteriography of the pelvic and leg area with step displacement]

By combining a 40 cm image amplifier, a DSA equipment, and the technique of step displacement, it became possible to demonstrate transvenously the arterial flow, beginning with the descent of the tibia, in four stages, using only two series of examinations. Venous digital subtraction arteriography of the pelvis/leg region was performed in 140 patients. The results were compared partly with arterial digital and analogue arteriographies as well as with surgical findings.

Comparison of the Auditec and Rintelmann recordings of the NU-6

Word discrimination scores were obtained for 30 normally hearing listeners using Auditec and Rintelmann recordings of the NU-6 presented at 60 and 70 dB SPL in quiet and in a background of multitalker noise at signal-to-noise (S/N) ratios of +12, +6, 0, and -6 dB. This was done to obtain normative data and to determine whether these two recordings of the same word lists were equivalent at conversational levels in quiet and in a noisy background. The word discrimination scores for each recording in quiet and at each S/N ratio were not significantly different when presented at 60 and 70 dB SPL. However, the word discrimination scores were significantly poorer as the S/N ratio became more severe, and the scores obtained with the Auditec recording were significantly poorer than those obtained with the Rintelmann recording at each S/N ratio. These differences between word discrimination scores using the Auditec and Rintelmann recordings were primarily attributed to the recorded level of the test word and secondarily attributed to carrier phrase and talker differences.

Telephone listening ability for hearing-impaired individuals

Forty-five subjects with bilateral sensorineural hearing losses were divided into three groups (N = 15/group) based on the audiometric configuration of their test ear. The subjects were evaluated in three listening conditions by assessing their word discrimination ability by presenting stimuli at 86 dB SPL (simulating the output of a standard telephone handset ) and most comfortable loudness (MCL) (simulating the output of a telephone amplifier handset ). The three listening conditions were TDH-39 earphone, unaided telephone, and aided telephone with their personal hearing aid acoustically coupled to a telephone handset . Results indicated that subjects with precipitous hearing losses had similar word discrimination scores for all three listening conditions at 86 dB SPL and MCL. Subjects with gradual slope or flat hearing losses had similar word discrimination scores with a TDH-39 earphone, unaided telephone, and their hearing aids acoustically coupled to a telephone handset at 86 dB SPL. The subjects with gradual slope or flat losses also had similar word discrimination scores across the listening modes at MCL, but they had better word discrimination scores in all listening modes when the word lists were presented at MCL compared with 86 dB SPL.

Single photon emission computerized tomography (SPECT) for estimates of liver and spleen volume

A simple procedure is described for estimates of liver and spleen volume using the imaging data obtained during single photon emission computerized tomography ( SPECT ). In vitro studies were carried out to obtain correlation and regression coefficients for volume estimations. Using these regression coefficients, we estimated liver and spleen volumes in 50 patients. Phantom and organ volumes were also calculated from transmission computed tomography (TCT), whose results served as the reference procedure against which SPECT -determined volumes were compared. The influence of radiotracer uptake on scintigraphic volume predictions was also assessed. For the in vitro measurements, SPECT volumes predicted the true volumes with a coefficient of correlation of 0.997. When in vivo SPECT volumes were correlated with those obtained by TCT, a coefficient in excess of 0.9 was achieved. SPECT volume determinations proved to be influenced by organ uptake of tracer; high liver uptake and low spleen-to-liver ratios gave the best results. It is concluded that SPECT imaging offers access to rapid and exact volume estimation.

Air-bone gap distributions in normal-hearing subjects

Unmasked (UM) and masked (M) AC and BC thresholds were obtained on 48 normal-hearing young adults. The UMAC and MBC thresholds were in agreement with standardized reference levels. The mean air-bone gaps (A-B G's) were less than 1 db for the three comparisons (UMAC minus UMBC; UMAC minus MBC; MAC minus MBC). The distribution of the individual Ss' A-B G's for each AC minus BC threshold comparison resembled a slightly flattened normal curve showing that some Ss had a positive while some had a negative A-B G. Over the 3 comparisons per S, 34% of the Ss exhibited negligible A-B G's of +/- 2.5 db, while 17.4% exhibited A-B G's greater than or equal to 7.5 db. The common rule that Ss with a normal conductive hearing mechanism have an A-B G of 0 db can only be used for mean data and not be applied to individual Ss tested in clinical practice or used for subjective BC calibration.

Phagocytosis in the uterus: A review

Phagocytosis is an important non-specific defense mechanism. Uterine phagocytosis is reviewed emphasizing factors which may alter the uterine phagocytic responses including the estrous cycle, pregnancy and the puerperium, and the presence of an intrauterine device. Implications of phagocytosis in therapy of and recovery from intrauterine infections are considered.

Telephone listening ability in a noisy background

Telephone handsets have a built-in side-tone feedback because the transmitter feeds back sound through the receiver, allowing users to monitor their voice levels. However, the side-tone feedback system also picks up background noise which interferes with the incoming speech signal. This study investigated the influence of side-tone feedback on the telephone listening ability of 30 normal-hearing subjects in a background of multitalker (MT) and white noise (WN) presented at 65, 75, and 85 dB SPL in two conditions where the side-tone feedback was present and in three conditions where the side-tone was eliminated. Telephone listening ability significantly decreased as the level of the noise increased for both MT and WN and for all listening conditions. Telephone listening ability was significantly poorer in the background of MT than WN for each noise level and listening condition. The primary finding was that telephone listening ability in a background of MT or WN at the higher levels was significantly improved when the side-tone feedback was eliminated by electronically disengaging or more simply by occluding the transmitter with the palm of the hand.

Influence of contralateral masking on bone-conduction thresholds

Two studies were conducted using normal-hearing listeners. In study 1, bone-conduction (BC) thresholds were obtained with contralateral masking at an effective level (EL) of 30 and 35 dB. In study 2, the EL of the contralateral masking equaled the magnitude of the occlusion effect (OE) plus a safety factor of 10 and 20 dB. Within each study, BC threshold shifts were evident at the higher compared with the lower ELs. Between studies, the highest BC thresholds were always obtained in the presence of the highest SPL of the masker which occurred in the 35 dB EL condition, whereas the lowest BC thresholds were always obtained in the presence of the lowest SPL of the masker which occurred in the OE + 10 dB condition. Even though the BC thresholds were influenced by the amount of contralateral masking, the BC thresholds obtained in each study were in good agreement with the new ANSI S3.26-1981 BC reference thresholds.

Frequency response and output variations of Radioear B-71 and B-72 bone vibrators

Frequency response curves were obtained for a Radioear B-71 and a B-72 bone vibrator with a revised Bruel and Kjaer model 4930 artificial mastoid. The curves for each vibrator were characterized by three resonant peaks which decreased in amplitude as frequency increased. The maximal output voltage variations of the artificial mastoid were less than or equal to 2 dB for each vibrator at all audiometric frequencies (+/- 3%), except for the B-72 at 4000 Hz where the variation was 6.9 dB. Overall, the findings were interpreted to question the use of a +/- 3% frequency tolerance for the generation and calibration of reference bone conduction thresholds.

Acoustic radiation from bone vibrators

Our purpose was to investigate the influence of acoustic radiation produced by bone vibrators at 4000 Hz on bone conduction (BC) testing. In one study, BC thresholds were obtained with a Radioear B-70A, B-71, and B-72 vibrator when the subject's ear canal was unoccluded and occluded. In another study, probe-tube microphone measurements were made just inside the entrance to the ear canal for each vibrator and for an air conduction source at comparable sensation levels. Results of both studies were interpreted to indicate that the B-70A and B-71 produced minimal acoustic radiation. However, the B-72 was found to have excessive acoustic radiation which would be sufficient to influence BC thresholds and produce an invalid high-frequency air-bone gap.

The Beltone 5b artificial mastoid: theoretical characteristics and performance measurements

Early versions of the Beltone artificial mastoid system were designated as model 5A. Later versions were designated as model 5B due to design modifications which changed the mechanical impedance parameters. The theoretical impedance characteristics of the 5B were considerably lower than for a comparison 5A. Compared with a B & K model 4930 (new pad) artificial mastoid, the 5B had a lower impedance (closer to ANSI values) from 500 to 2000 Hz and a slightly higher impedance at 250, 3000, and 4000 Hz. Discrete and continuous output voltage measurements with a constant input revealed that the performance of the 5B was also different compared with a 5A and the B & K model 4930 for different vibrator types. Bone conduction thresholds for a Radioear B-70A, B-71, and B-72 vibrator were obtained on 30 trained normal-hearing listeners. Adjusted threshold force levels needed to achieve normal-hearing bone conduction thresholds are presented for calibrating bone vibrators in clinical use with a Beltone 5B artificial mastoid.

[Ultrasound in the diagnosis of thyroid disease (author's transl)]

The article reports on the technique of examination, on echo patterns and their pathomorphological classification, incorporation of sonography in the pattern of thyroid diagnosis based on nuclear medicine, differential diagnosis of echo patterns, and significance of sonography.

Attenuation characteristics of hearing aid earmolds

The purpose of this study was to determine the attenuation characteristics of several hearing aid earmolds. Six earmolds and an E-A-R earplug modified to act as an earmold were evaluated according to the standard procedure. The six earmolds consisted of two types (shell and skeleton) having different materials (Lucite and vinylflex) and different styles (normal and tragus lock). The traditional earmolds provided approximately 17 dB less attenuation as compared with the E-A-R earmolds. The attenuation provided by the traditional earmolds was not influenced by the type, material, or style. The traditional earmolds had a noise reduction rating of less than 3.3 dB, whereas the noise reduction rating for the E-A-R earmolds was greater than 18.2 dB. Traditional earmolds should not be considered as a substitute for a hearing protection device. However, E-A-R earmolds could be used as a substitute for a hearing protection device provided the level of the noise minus the noise reduction rating would be acceptable.

Clinical significance of the relative intelligibility of pictorially represented spondee words

The relative intelligibility of 20 pictorially represented spondees were found for 40 normal hearing children between 3 1/2 and 5 1/2 years old. The range of the level of relative intelligibility was 5.3 dB. A spondee threshold (ST) was obtained for 60 different children between 3 1/2 and 5 1/2 years old in a 2 dB (N = 30) or a 5 dB step (N = 30) method for three sets of pictorially represented spondees (six pictures per set) having low, mid, and high levels of relative intelligibility. The ST's using a 2- or 5-dB step were not significantly different regardless of picture set level of relative intelligibility. ST's obtained with the picture sets having different levels of relative intelligibility were significantly different from each other. It was suggested that clinical consideration be given to the use of pictorially represented spondees which were identified at the lowest levels of relative intelligibility to increase the efficiency and precision of the ST measurement in children.

[Sonographic renal diagnosis in paediatrics (author's transl)]

Sonography is a method without risk but of high diagnostic value. Hence, it is extremely well suited for paediatric examination. In our opinion, this method should rank first among all other examination methods when clarifying inflammatory conditions of kidneys and of the efferent urinary tract, whereas in all other problems sonography continues to rank second behind the urogram. Both examinations together, which account for a diagnostic safety of more than 95%, are employed to decide whether and to what extent other and more invasive and complicated measures will have to be taken.

[Possibilities of errors in the sonographic diagnosis of renal tumours (author's transl)]

Artefacts or not completely visualised renal contours can lead to the erroneous diagnosis "renal tumour". This false diagnosis is mostly avoidable by means of accurate examination technique. Further radiological examination will be required only in exceptional cases. Incompletely visualisable parenchymal ridges with socalled incomplete multiple kidneys frequently create the impression of an intrarenal tumour and indicate the need for further clarification. There is a relatively high degree of uncertainty in intrarenal space-occupying processes below 2.5 cm diameter, as far as structural analysis is concerned. In such cases, provided a sufficiently strong clinical and roentgenological suspicion is sustained, angiography and, if necessary, exposure, should be recommended on a rather liberal basis.

Acoustic neurinoma in a child: a case study

This case study reports the audiological and surgical findings for a nine-year-old boy with an acoustic neurinoma. He was suspected of having a right ear retrocochlear lesion following three audiological evaluations in four years. The initial evaluation indicated normal hearing ability. The second and third evaluations indicated a progressive right ear hearing loss, characterized by reduced word discrimination ability and absent acoustic reflexes. The patient had a 5 cm acoustic neurinoma compressing and adherent to the brain stem. The tumor was successfully removed following three operations employing an otoneurological and neurosurgical team approach through a retromastoid exposure. Postoperative recovery was uneventful. Facial nerve function was not disturbed, however attempts to preserve hearing on the involved side were not successful.