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Biomedical subjects

M Sorri

Publications and source records attributed to M Sorri.

At least 37 records · Page 2Linked to original sources

More education in paediatric audiology needed for child welfare clinic nurses and doctors.

Opinions on formal and further education in paediatric audiology were surveyed by interviewing nurses and doctors in 28 Finnish child welfare clinics. Over half of the nurses recalled that they had been taught hearing screening during their period of practical training. Regarding formal teaching in paediatric audiology, the majority of doctors referred to courses in either otolaryngology, paediatrics or both. None of the doctors and only three of the nurses had taken part in any updating courses dealing with paediatric audiology during the last three years, and it turned out that no such courses had been arranged in three of the five hospital districts. However, 17 out of the 27 doctors and 23 out of the 28 nurses expressed their interest in further education. The present amount of formal education in paediatric audiology was ascertained from all five Finnish medical faculties and the five nursing schools in the provinces of Oulu and Lapland. The university departments of otolaryngology carry the major responsibility for teaching in paediatric audiology, which includes one to two hours of lectures and none to four hours of tutorials, depending on the faculty concerned. The amount of audiometric training at nursing schools varies from none to five hours and that of lectures in otolaryngology from three to twenty hours. Better co-ordination between departments of otolaryngology, general practice and paediatrics is needed when arranging teaching in paediatric audiology for medical students. Trainee child welfare nurses seem to need more guided practice in audiometry, and there is an obvious need for increasing the amount of practice in audiological departments. Specialist clinics should plan and implement a programme for updating training in paediatric audiology, including evaluation of the programme.

Audiology↗

Prevalence figures for mild hearing impairments cannot be based on clinical data.

The target population of the present study consisted of a 1-year (July 1985-June 1986) birth cohort from northern Finland. The prevalence of even slight hearing impairments (any threshold from 0.5 to 4 kHz > or = 25 db) at the age of 7 years was investigated among those 8,713 children still living in the area. The subjects for clinical audiometry were obtained in two ways. First, the standard clinical practice brought about 541 children, either with non-confirming results from their child welfare clinic screenings, suspected by their parents or already diagnosed as hearing impaired at a hospital. Secondly, in addition to this group, a random sample of 1,009 children, out of the 8,172 children not suspected, were also invited for audiometry. Of the clinical material, 101 children out of the 438 investigated were found to have impaired hearing according to the above criteria, and another 27 children out of the 789 investigated were obtained from the random sample. The estimated over-all prevalence of hearing impairments, even with the slight ones included, turned out to be 3.9% (95% confidence interval, CI, 2.7-5.7). Only 32% of the hearing impairments could be obtained according to the standard clinical policy! In conclusion, one cannot rely on clinical data when calculating prevalence figures for mild hearing impairments.

Audiometry↗

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↗

Hearing in 55 to 75 year old people in northern Finland--a comparison of two classifications of hearing impairment.

A total of 5,400 persons from different age groups was randomly selected from the population register for the study, and of the 1,620 55 to 75 year old persons invited, 1,233 attended the check-ups (76.1%). Air conduction pure tone thresholds were measured at the frequencies of 0.25, 0.5, 1, 2, 3, 4, 6 and 8 kHz. The findings were interpreted according to both the EU and WHO classifications. According to the WHO classification, 1,046 subjects (85.0%) had normal hearing and 124 persons (10.1%) had a mild hearing impairment, 44 (3.6%) a moderate, 13 (1.1%) a severe and 3 (0.2%) had a profound hearing impairment. According to the EU classification, 758 subjects (61.6%) were found to have normal hearing, a mild impairment was observed in 363 persons (29.5%), a moderate hearing impairment in 96 (7.8%) and a severe impairment in 13 (1.1%) persons. None had a profound hearing impairment. The difference between these classifications is remarkable as is evident in even this small study. A thorough discussion on the role of different gradings for hearing is needed.

Aged↗

New speech-in-noise test in different types of hearing impairment.

A new test was developed to assess speech recognition in noise. The test was designed to be run in a personal computer supplied with a sound card. One thousand disyllabic test words and noise were stored in digitized form on the hard disk of the computer. The measure given by this test is speech recognition threshold in noise (SRTN) corresponding to 50% recognition. The present series of 180 cases with various hearing impairments and 39 controls were examined with speech-in-noise test and conventional audiometry. In keeping with earlier studies, the SRTN turned out to be significantly elevated in cases with sensorineural hearing impairment; this elevation was related to the grade of hearing impairment. On the other hand, no essential difference was seen between the SRTN values of subjects with mixed hearing impairment and persons with normal hearing.

Adult↗

A comparison of three vibrators in static posturography: the effect of vibration amplitude on body sway.

In static posturography, proprioception is often disturbed using vibrators applied bilaterally to the calf muscles. The effect of vibrator amplitude on body sway was compared in static posturography using bilateral vibrators on the calf muscles of 30 healthy male military conscripts at frequencies of 50 and 90 Hz. Postural stability was measured in terms of BSV (body sway velocity), and maximal displacements of the centre of force (MAXY, MAXX) in the anterio-posterior and lateral directions. In comparing the effects of vibration to base stance without vibration, BSV seemed to be the most sensitive parameter. A vibration of 50 and 90 Hz significantly influenced BSV values with the two most eccentric loads, an effect which could not be confirmed using any other parameter. This result could be obtained even with a small amplitude (around 0.7 mm free/0.3 mm fixed) in our healthy subjects. The BSV effects may be even more pronounced in clinical work with patients and postural disorders. Thus, when proprioceptive stimulations is used in posturographic measurements, differences in the tested magnitude of the stimulation amplitude with a constant frequency will significantly affect postural stability, even in healthy subjects.

Acceleration↗

Dynamic multivariate modelling: day care and consultation rate for acute otitis media.

A random sample of 2,512 children was monitored to the age of 2 years to study the effects of various risk variables on the consultation rate of acute otitis media. A total of 3,283 episodes of acute otitis media of 2,411 children with a follow-up time of at least 1 month were included in the analysis. During a 3 week-period after onset of the episode, the number of unplanned visits varied between 0 (2,544 episodes; 77.5%) and 6 (2 episodes; 0.1%). The children with day care outside their home showed a diminished risk for unplanned visits during the first week. The odds ratio (OR) and 95% confidence interval (CI) for children in family day care were 0.58 and 0.39-0.8, and 0.72 and 0.47-1.11 for children in nursery day care, respectively. During the second and third weeks the results were reversed: the above odds ratios should be multiplied by interaction terms 2.19 (CI 1.41-3.42; new OR 1.27) for children in family day care and 1.57 (CI 0.97-2.54; new OR 1.13) for children in nursery day care.

Acute Disease↗

Chronic otitis media with effusion in infancy. How frequent is it? How does it develop?

OBJECTIVE: To study the occurrence and development of chronic otitis media with effusion in infancy. DESIGN: A retrospective birth cohort with a 2-year follow-up. Infection data were gathered from medical records; background information came from questionnaires. SETTING: Primary health care centers, hospitals, and private practices in 10 randomly selected local government districts in the two northernmost provinces of Finland. SUBJECTS: A random sample of 2512 children from the cohort. MAIN OUTCOME MEASURES: Chronic otitis media with effusion determined as a minimum of 2 months of asymptomatic middle ear effusion revealed by tympanocentesis and specific operative findings. RESULTS: The periodic prevalence rate of chronic otitis media with effusion up to the age of 24 months was 4.4% (95% confidence interval, 3.5 to 5.3). The maximum risk was at age 16 months. The number of acute otitis media episodes among children who developed chronic otitis media with effusion was more than double that of normal healthy children before the onset of chronic inflammation and about five times as high during prolonged mucous middle ear effusion. Inadequate treatment of prior acute otitis media was not the reason for the chronic inflammation, which was a direct continuation of an acute episode in only half of the cases and was otherwise preceded by a latent period of varying duration. CONCLUSIONS: Chronic otitis media with effusion, which may cause adverse developmental effects such as delayed language development, is a fairly common disease in infancy and is closely related to acute otitis media episodes.

Acute Disease↗

Risk factors for chronic otitis media with effusion in infancy. Each acute otitis media episode induces a high but transient risk.

OBJECTIVE: To examine the effects of a history of acute otitis media and different extrinsic factors on the risk of chronic otitis media with effusion in infancy. DESIGN: A retrospective birth cohort with a 2-year follow-up. Infection data were gathered from medical records and background information came from questionnaires. The monthly risk of chronic otitis media with effusion was dynamically modeled to control the confounding effects and time-dependency of the risk factors. SETTING: Primary health care centers, hospitals, and private practices in 10 randomly selected local government districts in the two northern most provinces of Finland. SUBJECTS: A random sample of 2512 children from the cohort. MAIN OUTCOME MEASURES: Chronic otitis media with effusion, defined as a minimum of 2 months of middle-ear effusion, usually is disclosed by tympanocentesis and specific operative findings. RESULTS: Previous acute otitis media episodes were the greatest risk factor. Each acute episode induced a highly increased risk (odds ratio, 11.9; 95% confidence interval, 5.7 to 24.9) that disappeared in 3 months. Successive episodes were risky, but this risk also decreased rapidly. Other significant risk variables were attendance at a day nursery (odds ratio, 2.56; confidence interval, 1.17 to 5.57), male sex (odds ratio, 2.17; confidence interval, 1.37 to 3.44), and autumn season (odds ratio, 1.99; confidence interval, 1.11 to 3.55). CONCLUSIONS: Acute otitis media episodes constitute the greatest risk of chronic otitis media with effusion. Each episode has a high transient risk for 3 months but no further direct effect on the risk.

Acute Disease↗

Otitis media and long-term follow-up of hearing.

The present material is based on a birth cohort of 2,512 children followed up from the antenatal period. Data on middle ear infections were collected until the children were 7 years. At the age of 7, audiometry was performed on 298 of them. For reasons other than middle ear infection, 32 children were excluded and the final material comprised 266 children. Only those children with clear differences in their history for otitis media were analysed. Although the pure tone averages (0.5-3 kHz) showed no major changes, different mean air-conduction (AC) thresholds were associated with different histories of otitis media. The 35 healthy children (with no otitis media episodes until 2 years of age) showed the best mean AC thresholds. The 51 children with recurrent acute otitis media (RAOM; > or = 4 episodes of acute otitis media) showed worse thresholds at the high frequencies and those 13 who had had secretory otitis media (SOM) at all frequencies. The children with a history of otitis media, either RAOM or SOM, more often had hearing thresholds exceeding 20 dB. Our results might indicate inner ear involvement in these long-term follow-up hearing thresholds.

Acute Disease↗

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↗

Which children are being operated on for recurrent acute otitis media?

OBJECTIVE: To examine at the population level which children were operated on for recurrent acute otitis media episodes, how ill they were, and what factors affected the operation rate. DESIGN: A retrospective birth cohort with an approximate 2-year follow-up. Infection data were gathered from medical records, and background information was gathered from questionnaires. SETTING: Primary health care centers, hospitals, and private practices in 10 randomly selected local government districts in the two northernmost provinces of Finland. SUBJECTS: A random sample of 2512 children from the cohort. OUTCOME MEASURES: Adenoidectomy and/or tympanostomy tube insertion. RESULTS: Only one of 10 of those with actual recurrent disease (> or = 4 episodes) had been operated on, and three of every five children operated on, in fact, had rather few episodes. The operation rate among those children with only a few episodes was increased by factors such as consulting an ear, nose, and throat specialist (risk ratio [RR], 13.0; 95% confidence interval [CI], 7.6 to 22.2); parental exaggeration of the episodes (RR, 6.7; 95% CI, 3.8 to 11.9); having the first episode under 6 months of age (RR, 4.5; 95% CI, 2.5 to 7.9); recurrent respiratory tract infections (RR, 3.3; 95% CI, 1.9 to 5.7); male sex (RR, 2.6; 95% CI, 1.4 to 4.6); urban domicile (RR, 2.4; 95% CI, 1.1 to 4.9); and day care (RR, 2.1; 95% CI, 1.1 to 3.8). The decision to operate was more or less a random phenomenon among those children with numerous episodes. CONCLUSIONS: Physicians at the primary care level should be familiar with these pitfalls concerning patient selection so that the operations are targeted at those children who are most seriously ill.

Acute Disease↗

Effect of occupational noise on the course and outcome of pregnancy.

OBJECTIVES: The goal of this investigation was to examine the effects of occupational noise during pregnancy prospectively. METHODS: The exposed group [continuous A-weighted sound level (LAeq(8 h)) > or = 78 dB] consisted of 111 pregnant women, and the reference group comprised 181 pregnant women with approximately similar work conditions but without noise exposure. The noise-exposed women had more frequently other inconveniences in their work, however, like shift work, impulse noise exposure, vibration, and a high or low temperature. RESULTS: With the limit of 78 dB (LAeq (8 h)), the course and outcome of pregnancy did not differ between the groups. When the noise exposure was 90 dB (LAeq (8 h)) or more, a decline in birthweight, either absolute [mean 3304 (SD 585) g for the exposed versus mean (SD 548) g for the unexposed, 95% CI of mean difference -471--+15 g] or related to the gestational age (below the 10th percentile [5 of 25 (20%) versus 13 of 180 (7%)]), was seen. These findings were more pronounced if the woman was simultaneously exposed to a standing work position or shift work. CONCLUSIONS: Working in high noise exposure can be considered a form of risk during pregnancy.

Adult↗

Noise and hearing loss in reindeer herders.

Air conduction hearing thresholds were examined in 512 reindeer herders (aged 18-65 years, clinically normal ears) to evaluate the prevalence of noise-induced hearing loss. The hearing thresholds at 6 kHz showed significant noise-type impairment of hearing compared with those in the ISO 7029 standard or a Finnish reference population. The subjects were exposed to noise mainly in the use of snowmobiles and chain saws: daily noise exposure ranged from 93 to 104 dB(A). The age adjusted hearing thresholds deteriorated with the total noise exposure time, especially at 3 and 4 kHz. The prevalence of significant (class IV) hearing loss was 15% and impairment of hearing was frequently found even in the younger age groups. Although the use of ear protectors seems to be increased among reindeer herders, it still appears to be insufficient, and efforts to promote their use are needed.

Adult↗

The repeatability of posturographic measurements and the effects of sleep deprivation.

The repeatability of posturographic measurements and the effects of sleep deprivation on them were investigated in 23 volunteers over a period of four months. Postural stability was studied by evaluating body sway velocity and the maximal and average vibration-induced shifts of the centre of pressure in the anterio-posterior and lateral directions. The posturographic test was performed with and without exposure of the calf muscles to vibration. Subjects were tested both with their eyes open and closed, and the measurements were performed weekly during the first month and once every month thereafter. The interindividual results differed more than the intraindividual ones, indicating that posturographic measurements are most suitable for functional monitoring in one person's tests. The dispersion of the results did not diminish with time, nor did the body sway decrease. The findings suggest that no learning takes place in nontrained persons. In the second part of the research, measurements were performed twice after the subjects had been awake the previous night or 24 hours. Postural stability did not deteriorate in this situation.

Adult↗

Control of the temporal aspect when considering risk factors for acute otitis media.

A random sample of 2512 children was monitored to age 2 years to study the biologic effects of various risk variables on acute otitis media using a new dynamic modeling that controls both the confounding effects and time dependency. Dynamic modeling proved to be superior to conventional approaches, both the random and systematic error being much smaller and the effect estimates being biologically interpretable. The major risk factors were the existence of a previous episode of acute otitis media in general (odds ratio, 2.03; 95% confidence interval [Cl], 1.81 to 2.25) or particularly during the preceding 3 months (odds ratio, 3.74; 95% Cl, 3.40 to 4.10) and attending a day nursery (odds radio, 2.06; 95% Cl, 1.81 to 2.34). As the form of day care is the only modifiable risk variable of significant importance and previous episodes entail a risk of future ones, infants should be cared for at home, particularly after they have already experienced an episode of acute otitis media.

Acute Disease↗