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Biomedical subjects

H Löppönen

Publications and source records attributed to H Löppönen.

At least 19 recordsLinked to original sources
PubMed2001

Carhart notch effect in otosclerotic ears measured by electric bone-conduction audiometry.

The Carhart notch is an elevation in the middle-frequency bone-conduction threshold of an ear with clinical otosclerosis. The study population consisted of 138 patients with clinical otosclerosis. Conventional air-conduction (AC) and bone-conduction (BC) and electric bone-conduction (EBC, with Audimax 500 audiometer) thresholds were measured 2 weeks before and 7 months after stapes surgery. The EBC thresholds were converted from mA values to dB SPL to compare the results obtained with the different methods. The mean differences in the BC thresholds before and after the operation were 3.2 dB (95% CI 1.9-4.6) at 1 kHz and 7.6 dB (95% CI 6.1-9.1) at 2 kHz. The mean differences in the EBC thresholds were 5.4 dB (95% CI 3.8-6.9) at 1 kHz and 5.3 dB (95% CI 3.4-7.1) at 2 kHz. Thus, both methods showed a distinct Carhart notch effect.

Audiometry, Pure-Tone↗
PubMed2000

Nasalance scores in snoring children with obstructive symptoms.

OBJECTIVE: Snoring and the sleep apnea syndrome (OSAS) in children are usually caused by adenotonsillar hypertrophy, which may affect air escape into the nose and nasal resonance. A microcomputer-based system makes it possible to objectively determine whether the oral passage is adequately separated from the nasal passage during phonation. The score thus obtained is called nasalance. This study was conducted to verify whether there exists differences in nasalance between primary snorers and OSAS-children. DESIGN: Fifty-three habitually snoring children (31 boys), mean age 6.1 years (range 3.2-10.5 years), were subjected to overnight sleep polygraphy (PG) and nasalance measurements with the Nasometer 6200. The study was successfully repeated 6 months later on 36 children. RESULTS: Nineteen children had obstructive apnea-h ypopneaindex (OAHI)> 1 on overnight polygraphy (OSAS-children), while 32 were considered primary snorers (PS), (OAHI<1). No statistically significant difference in nasalance scores was found between the OSAS- and PS children. Both groups of children had somewhat higher mean nasalance values both for oral and nasal passage sentences than the normative values for Finnish speech. In general, the most habitual snorers had lower nasalance scores than the less frequently snoring children (P=0.05). Earlier adenoidectomy or palatine tonsillar size did not have a significant influence on the nasalance. Adenotonsillectomy did not affect the nasalance scores of the nine children operated on during the follow-up period. CONCLUSIONS: According to the present study, nasalance measurements cannot be used to predict the incidence of OSAS among snoring children.

Child↗
PubMed2000

Snoring and obstructive sleep apnea in children: a 6-month follow-up study.

BACKGROUND: Snoring children may present symptoms suggestive of obstructive sleep apnea syndrome (OSAS). Different and controversial methods to establish the diagnosis and to choose the treatment modalities have been proposed. OBJECTIVES: To study children with symptoms raising the suspicion of OSAS with overnight polysomnography (PSG). To evaluate the efficacy of adenotonsillectomy as treatment of pediatric OSAS and to elucidate the natural history of OSAS and primary snoring. DESIGN: A controlled, prospective, nonrandomized clinical trial. SETTING: Academic medical center. SUBJECTS: Fifty-eight snoring but otherwise healthy children aged 3 to 10 years with symptoms suggestive of OSAS underwent PSG twice, 6 months apart. Thirty healthy children served as controls. RESULTS: Twenty-seven children had OSAS with an obstructive apnea/hypopnea index greater than 1, while 31 had primary snoring. There were statistical differences in the symptoms and signs among the 3 study groups. Adenotonsillectomy was curative in the 21 children with OSAS who were operated on. Obstructive apneas and hypopneas in the healthy, nonsnoring children were almost nonexistent in this study. CONCLUSIONS: Half of the children or fewer with symptoms suggestive of OSAS actually had the condition. Clinical symptoms may raise the suspicion, but it is not possible to establish the diagnosis without PSG. Because snoring and obstructive symptoms may resolve over time, a normal PSG finding may help the clinician decide on an observation period. Adenotonsillectomy is curative in most cases of pediatric OSAS. Obstructive symptoms may continue after adenoidectomy alone.

Adenoidectomy↗
PubMed2000

[Imaging the ear].

Explore the source record for details and available documents.

Diagnostic Imaging↗
PubMed1997

The growth rate of osteomas of the paranasal sinuses.

Paranasal sinus osteomas are benign tumours, occasionally known to cause complications. They have a tendency to grow slowly, but the growth rate has never been evaluated previously. We retrospectively studied 44 patients with paranasal sinus osteomas. In 13 out of the 23 patients who underwent at least two sinus radiographs at different times some growth was seen. The mean growth rate of these 13 osteomas was 1.61 mm/yr, range 0.44 to 6.0 mm/yr. The endoscopic technique is a good method for the removal of osteomas and obliteration of the frontal sinus does not seem to be necessary. Two patients having osteomas with intracranial expansion are described.

Adolescent↗
PubMed1997

Computed tomography data based rapid prototyping model of the temporal bone before cochlear implant surgery.

Rapid prototyping (RP) technique allows automatic fabrication of 3D model parts. This method was applied to make a temporal bone model before cochlear implant surgery. A helical CT scan is used to acquire high resolution data from the middle and the inner ear of the patient. From the scanning data bone structures and soft tissues can be separated because their different grayscale pixel values. By using a guided image processing tool the desired parts of the anatomy can be extracted and 3D data created. The segmented data are processed to the form suitable for creating a high accuracy RP model. The RP model is made in the stereolithography (SLA) process by means of a computer guided HeCd laser beam inducing polymerisation of acrylic solution as it passes layer by layer over the surface of the polymer solution. In this prototype model the anatomy of the temporal bone can be clearly visualised, including, e.g., mastoid cells, tympanic cavity, bony canal of facial nerve, and round and oval windows. The inner ear spaces including vestibule, semicircular canals and cochlear turn are also shaped. The transparent acrylic material allows bonelike mechanical handling. The RP model can be dissected and used in individual surgical planning and simulation prior to cochlear implantation.

Cochlear Implants↗
PubMed1997

Snoring children: factors predicting sleep apnea.

Many snoring children present obstructive symptoms according to their parents. The seriousness of the symptoms and the possibility of the obstructive sleep apnea syndrome (OSAS) in these children may be difficult to judge on the basis of the clinical findings and the patient's history only. In order to evaluate snoring children's relative risk (RR) to have OSAS, their symptoms and signs, as reported by the parents, and clinical findings were compared with the results of overnight polysomnography (PSG). An obstructive apnea index (AI) > or = 1 in PSG was regarded as the criterion for OSAS. The mean AI was 1.55 (range 0-15), and 29 children had a pathological AI, while 49 had a normal PSG recording. Apneic episodes every night detected by the parents was the most important single risk factor for OSAS (RR 3.6, 95% confidence interval (CI) 1.7-7.7). The RR ratio decreased when apneas appeared less frequently, but any detected apnea was still a single risk factor (RR 1.4, CI 1.2-1.8). The other risk factors of night-time symptoms were constant snoring (RR 1.5, CI 1.0-2.1) and restless sleep (RR 2.1, CI 1.1-4.0). Of the daytime symptoms, absence of excessive sleepiness was a protective factor against OSAS (RR 0.3, CI 0.1-1.0). Previous adenoidectomy was found to be a risk factor (RR 1.7, CI 1.1-2.7), as was tonsillar enlargement (RR 1.4, CI 1.1-1.8). These two findings suggest that the epipharyngeal space does not play a central role in the development of OSAS in children. OSAS cannot be reliably diagnosed without PSG, which is the most important examination for snoring children with obstructive symptoms. For clinical decisions, the consideration of risk factors is essential.

Adenoidectomy↗
PubMed1995

Sleeping positions and dental arch dimensions in children with suspected obstructive sleep apnea syndrome.

The present paper analyzed the association between children's sleeping positions and dental arch morphology. The sleeping patterns of 27 children, aged 3 to 10 yr, suspected of having the obstructive sleep apnea syndrome (OSAS) were studied by polysomnography (PSG) and videotape recordings under laboratory conditions. The PSG recordings were used to calculate the apnea index (AI) and the relative time spent sleeping on the back, and the videotapes to categorize distinctly different sleep and head postures. Plaster casts were made for the assessment of dental arch morphology. Sleeping predominantly on one's back, was associated with a reduced maxillary intercanine width, while prolonged head extension during sleep correlated inversely with the overjet. The subjects with the highest AI scores (> 4) had larger dental arches. We suggest that sleeping on the back causes a more posterior tongue position, reducing its moulding effect on the anterior dental arch. As nasopharyngeal airway obstruction in OSAS-patients might trigger an anterior tongue position to secure a free airway passage, there will be increased lingual pressure on the dental arches, leading to their dimensional increase.

Child↗
PubMed1995

Objective real ear measurements of bone-conduction hearing aid performance.

Conventional bone-conduction and bone-anchored hearing aids are tested with skull simulator devices; individual adjustments are reliant on psychoacoustic free-field audiometry, which can be quite demanding for the patient. A method is presented in which the induced skull vibrations are measured with an accelerometer and then analysed with Fast Fourier Transformation (FFT). With this method, frequency characteristics, harmonic distortion and dynamic response can be analysed.

Bone Conduction↗
PubMed1995

Assessment of bone conduction prosthesis in situ.

Conventional and bone anchored bone conduction hearing aids can be tested with skull simulating devices and the individual adjustment rely on time consuming psychoacoustic audiometry in free-field which can be quite demanding for the patient. A method is presented in which the hearing aid induced skull vibrations are collected with an acceleromotor and recorded on a digital audio tape. The recordings are analysed with Fast Fourier 'Transformation (FFT) by using a signal processor. The free-field test signal can be either narrow-band or white noise. Changes in frequency characteristics can be easily monitored with white noise as signal, harmonic distortion and dynamic response can be analysed reliably by using pure tones. The inter-individual comparisons can be made when calibration is based on skull vibrations at the individual bone-conduction hearing thresholds. Two case reports are presented and discussed.

Adult↗
PubMed1994

Carhart notch and electric bone-conduction audiometry.

The Carhart notch is a depression in the bone-conduction audiogram of patients with clinical otosclerosis. The middle frequencies from 0.5 to 2 kHz, which correspond to the resonance frequency of the middle ear, can be substantially improved following successful stapes surgery. Twenty-nine consecutive patients with clinical otosclerosis were tested 2 weeks before and 7 months after stapes surgery with conventional air-conduction (AC) and bone-conduction (BC) audiometry and electric bone-conduction (EBC) audiometry using an Audimax 500 audiometer. The BC thresholds improved at 0.5-2.0 kHz corresponding to the Carhart notch. On average, the EBC thresholds remained more stable, showing no Carhart phenomenon, which supports the concept that EBC stimulation is not entirely equivalent to conventional BC audiometry, but has a different mode of action on the inner ear.

Adult↗
PubMed1992

ENG findings of shunt-treated hydrocephalus in children.

Thirty-eight hydrocephalic children (mean age 11.5 years; range 5.1-17.9) were examined on average 7.9 years after initial shunting. The etiology of the hydrocephalus was divided into 5 groups: perinatal intraventricular hemorrhage 14, congenital obstructive hydrocephalus 14, central nervous system infections 4, intracranial cysts 3, and intracranial anomalies 3 children. Electronystagmographic (ENG) examination included recording of spontaneous and positional nystagmus, the pendular eye tracking test, saccadic eye movements, optokinetic and caloric reactions. Only 5 children (13%) had a normal ENG. Thirty-one children (82%) had ENG pathology of the central type and 12 (44%) of the 27 successfully studied had pathological caloric reactions. Ten children (26%) had a combination of both central and vestibular pathology. There was no statistical difference between the boys and the girls or between different etiological groups. The high prevalence of vestibular pathology among these hydrocephalic children may be relevant to their impaired motor performance, because only 7 (18%) of the children studied exhibited normal motor performance in the neurological tests.

Adolescent↗
PubMed1992

High-frequency audiometry. Masking in electric bone-conduction audiometry.

Recently, the 'electric bone-conduction' (EBC) audiometer (Audimax 500) has been used to measure high-frequency (HF) hearing. With this audiometer stimulation is binaural. No commercial masking method was available. In this study, white noise from a Madsen OB822 audiometer and presented via Sony MDR-V4 dynamic earphones, was used for masking. The masking and cross-hearing effect was measured in 8 unilaterally deaf subjects and the masking procedure was tested with 104 young normal-hearing subjects. The results showed that the EBC signals can be masked with air-conduction signals, and thus, the EBC measurements reflect monaural thresholds. The minimum masking level was 50-60 dB SPL in the HF range. There were no cross-hearing problems in the HF range with the earphones used. At the frequencies 0.5-14 kHz, the better ear's masked EBC thresholds were on the average 2.6 dB (range 0-4.5 dB) poorer, compared with the binaural EBC thresholds, indicating a binaural summation effect.

Acoustic Stimulation↗
PubMed1992

Noise-induced low- and high-frequency hearing losses in Finnish conscripts.

Thirty-nine otologically healthy military conscripts were examined at the beginning and at the end of their 1-year service. On entry, they all showed normal findings during clinical otolaryngological examinations. The test battery included both conventional (0.25-8 kHz) and high-frequency "electric bone-conduction" (0.5-20 kHz) audiometry (EBC). The median pure-tone right ear thresholds at the end of service were 5 dB worse over the frequency range of 2-8 kHz compared with the thresholds at the beginning of the service. The difference was statistically highly significant (p = 0.00035). The median left ear pure-tone thresholds at frequencies of 0.25, 2, and 8 kHz were 5 dB worse at the end of the service compared to the thresholds at the beginning of the service. However, the difference was not statistically significant (p = 0.23). The median curves for the high-frequency (EBC) thresholds measured after the service showed worse thresholds over the whole frequency range compared to the median curves measured before the service. The greatest difference was seen in the highest frequencies (15-17 kHz) in both ears. The differences were statistically significant in both ears (p = 0.03 in the right ears; p = 0.01 in the left ears) when threshold values over the whole frequency range were analyzed. Since the otolaryngological history of these conscripts was uneventful during their service, the hearing deteriorations were considered to be caused by shooting practice.

Adolescent↗
PubMed1992

Secretory otitis media and high-frequency hearing loss.

31 children (mean age 13 years; range 8.5-17.2) who had been tympanostomy treated for SOM during the years 1977-1980 were invited for follow-up examination. 29 normal age peers were enrolled as controls. The test battery included clinical pneumotoscopical examination and conventional pure-tone audiometry as well as air-conduction and electric bone-conduction high-frequency audiometry. High-frequency hearing losses (6-18 kHz) were found as sequels of SOM. The median threshold difference between the SOM group and the controls varied from 0 to 10 dB depending on the frequency. The hearing losses were considered to be of the conductive type, and probably related to changes in the tympanic membrane and the middle ear caused by SOM. On the other hand, we found also sensorineural hearing losses suggesting lesion at the cochlear level.

Adolescent↗