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Biomedical subjects

M Sorri

Publications and source records attributed to M Sorri.

At least 19 recordsLinked to original sources
PubMed2006

A 3-year clinical follow-up of adult patients with 3243A>G in mitochondrial DNA.

OBJECTIVE: To follow the clinical course of patients with the mitochondrial DNA mutation 3243A>G for 3 years. METHODS: Thirty-three adult patients with the 3243A>G mutation entered a 3-year follow-up study. They were clinically evaluated annually, audiometry was performed, and samples were drawn for the analysis of blood chemistry and mutation heteroplasmy in leukocytes. Holter recording was performed three times during the follow-up and echocardiography, neuropsychological assessment, and quantitative EEG and brain imaging conducted at entry and after 3 years. RESULTS: The incidence of new neurologic events was low during the 3-year follow-up. Sensorineural hearing impairment (SNHI) progressed, left ventricular wall thickness increased, mean alpha frequency in the occipital and parietal regions decreased, and the severity of disease index (modified Rankin score) progressed significantly. The rate of SNHI progression correlated with mutation heteroplasmy in muscle. The increase in left ventricular wall thickness was seen almost exclusively in diabetic patients. Seven patients died during the follow-up, and they were generally more severely affected than those who survived. CONCLUSIONS: Significant changes in the severity of disease, sensorineural hearing impairment, left ventricular hypertrophy, and quantitative EEG were seen in adult patients with 3243A>G during the 3-year follow-up.

Adult↗
PubMed2005

Prevalence of large-scale mitochondrial DNA deletions in an adult Finnish population.

BACKGROUND: Large-scale mitochondrial DNA (mtDNA) deletions are associated with clinical conditions such as Kearns-Sayre syndrome and chronic progressive external ophthalmoplegia in adults and Pearson syndrome in children. Reported case series have suggested that deletions are not uncommon in the population, but their prevalence has not been documented. METHODS: The authors ascertained patients with clinical features associated with mtDNA deletions in a defined adult population in northern Finland. Buccal epithelial samples were requested from each patient fulfilling the selection criteria, and full-length mtDNA was amplified using the long PCR method. Deletion breakpoints were identified using sequencing. Patients with deletions were examined clinically. RESULTS: The authors identified four patients with single large-scale mtDNA deletions. The prevalence of deletions was calculated to be 1.6/100,000 in the adult population in the province of Northern Ostrobothnia (0.0 to 3.2; 95% CI). Analysis of incident cases from a neighboring province revealed two patients with deletions and yielded a similar population frequency. CONCLUSIONS: The frequency of large-scale mitochondrial DNA deletions is similar among populations, suggesting that there is a constant rate of new deletions.

Adult↗
PubMed2001

Hearing impairment in patients with 3243A-->G mtDNA mutation: phenotype and rate of progression.

The relationship between the phenotype and the genotype is complex in diseases caused by mutations in mitochondrial DNA (mtDNA). The 3243A-->G mutation in mtDNA frequently leads to sensorineural hearing impairment (HI), a phenotype that can be assessed in severity by audiometry; hence, consecutive audiograms can give an estimate of the rate of HI progression. We examined the audiological phenotype of 38 patients (14 men, 24 women; mean age: 45+/-14 years) who possessed the 3243A-->G mutation and who belonged to a population-based cohort ascertained in the province of Northern Ostrobothnia, Finland. The subjects took part in an otorhinolaryngologic examination, including audiometry. Factors modulating the severity of HI were analyzed, and the rate of HI progression was calculated. The better ear hearing level (BEHL) at frequencies 0.5, 1, 2, and 4 kHz (BEHL0.5-4kHz) was greater than 20 dB suggesting HI in 28 patients (74%). A good correlation (r=0.428, P=0.009) was found between BEHL0.5-4kHz and the degree of the mutant heteroplasmy. BEHL0.5-4kHz was worse in men than in women, and women outnumbered men among patients with normal hearing or mild HI. In addition, 181 consecutive audiograms were reviewed from 24 patients with HI. The rate of HI progression was calculated to be 2.9 dB/year in men and 1.5 dB/year in women, being clearly faster than the rates that have been observed in the corresponding age group in the general population. A high degree of mutant heteroplasmy, male gender, and age were found to increase the severity of HI. Phenotypic difference by gender may thus be a more universal phenomenon in mitochondrial diseases, not only being associated with Leber's hereditary optic neuropathy. This study provides the first estimate of the rate of disease progression among patients with the 3243A-->G mutation.

Cohort Studies↗
PubMed2001

Prognosis of hearing impairment in Ménière's disease.

The deterioration of hearing in Ménière's disease is known to be dependent on the individual and to be highly variable. In most cases, however, it leads to moderate hearing impairment. In order to be able to predict deterioration, we used multivariable modelling with a source population of definite cases of Ménière's disease diagnosed according to the latest recommended American Academy of Otolaryngology--Head and Neck Surgery criteria. The records of 205 patients were retrospectively analysed. Their earliest and latest pure-tone air conduction audiograms were used to evaluate the long-term effects of the disease on hearing. The effect of age and the follow-up period were calculated for different frequencies (0.125-8 kHz) and for the pure-tone average over the frequencies 0.5 to 4 kHz (PTA0.5-4 kHz). Deterioration in PTA0.5-4 kHz was approximately 1 dB/year due to the duration of the disease and approximately 0.5 dB/year due to aging. Hearing impairment in Ménière's disease appeared to increase linearly with the duration of the disease for patients < 50 years of age, but in the older subjects the effect of the duration of the disease decreased. Both aging and the duration of the disease affected the hearing level. The duration of the disease did not seem to have any statistically significant effect on the difference between the two ears. The difference that occurred at the onset of the disease remained until presbyacusis in the better ear reached the hearing level of the worse ear. The difference in hearing deterioration between men and women was not significant.

Adult↗
PubMed2001

HI-SIMv1.0--towards the virtual reality of hearing impairments.

The virtual reality of hearing impairments has obvious practical applications in areas such as audiology, speech therapy and hearing aid technology and serves as an informational tool for the family members of the hearing impaired. To simulate hearing impairment, a CD-ROM with filtered speech material accessible through a graphical user-interface was produced; the user-interface was created with standard multimedia tools. The CD-ROM, HI-SIMv1.0, intended as an interactive educational tool, offers a virtual experience of the effects of a selection of common types of hearing impairment. The options available in this simulation include grade of hearing impairment, audiometric configuration and the type and level of background noise. Word recognition scores can be computed for standard Finnish audiometric material.

Acoustic Stimulation↗
PubMed2001

Will hearing healthcare be affordable in the new millennium.

Calculations of the needs of healthcare, hearing healthcare included, are usually based on clinical data rather than on valid prevalence figures. According to our recent population study, the number of citizens needing hearing aids in Finland will be twice the figure usually presented, 280 000 for the country as a whole (population 5.1 million). The penetration of hearing aids was only 41%. Taking this and the ageing of the population into account, the economic challenges of hearing healthcare will be alarming in the new millennium.

Aged↗
PubMed2001

Provision of hearing aid services: a comparison between the Nordic countries and the United Kingdom.

About one in five adults has some form of hearing impairment. This paper reports on a survey which found significant variation in the provision of hearing aid services across Denmark, Finland, Norway, Sweden and the United Kingdom. Per capita expenditure levels were estimated to vary from under 3 euros in the UK to nearly 10 in Denmark and Norway. Annual figures for the number of people receiving at least one aid varied from around eight per 1,000 in the UK and Denmark to 2.2 in Finland. Over 50% of hearing aid users in Norway and Denmark are estimated to have bilateral aids, compared to under 15% in the UK. Estimates of the number of people who have a hearing aid in these countries are considerably lower than the number who have a hearing impairment. More research is needed to verify the true extent of these differences and their cause.

Adult↗
PubMed2000

Can the impact of hearing impairments be modelled?

The effects of two simulated hearing impairments (presbyacusis) on speech perception were investigated in two groups of normally hearing subjects (30 and 48 subjects, respectively). Eight patients with presbyacusis with similar hearing impairment to those in the latter simulation served as the clinical material. Word recognition scores were measured in quiet and in cocktail party noise (S/N + 18 dB and + 12 dB). The recognition scores deteriorated in the less favourable listening conditions. Somewhat surprisingly, the hearing impaired subjects showed better word recognition scores in quiet and especially in moderate noise. Subjective complaints on speech perception difficulties in noise on a visual analogue scale behaved quite logically; the hearing impaired subjects' subjective experiences were no milder than those of the normally hearing during the simulation. The better results in word recognition shown by the hearing aid candidates may be explained by habituation to the hearing impairment.

Adolescent↗
PubMed1999

Expression of CYP2A genes in human liver and extrahepatic tissues.

Members of the human cytochrome P450 2A (CYP2A) subfamily are known to metabolize several promutagens, procarcinogens, and pharmaceuticals. In this study, the expression of the three genes found in the human CYP2A gene cluster was investigated in the liver and several extrahepatic tissues by gene-specific reverse transcriptase-polymerase chain reaction (RT-PCR). All three transcripts (CYP2A6, CYP2A7, and CYP2A13) were found to be present in liver. Quantitative RT-PCR analysis showed that CYP2A6 and CYP2A7 mRNAs were present at roughly equal levels in the liver, while CYP2A13 was expressed at very low levels. Two putative splicing variants of CYP2A7 were found in the liver. Nasal mucosa contained a low level of CYP2A6 and a relatively high level of CYP2A13 transcripts. Kidney, duodenum, lung, alveolar macrophages, peripheral lymphocytes, placenta, and uterine endometrium were negative for all transcripts. This survey gives a comprehensive picture of the expression pattern of CYP2A genes in liver and extrahepatic tissues and constitutes a basis for a search for functional CYP2A forms and their roles in chemical toxicity in liver and nasal mucosa.

Aryl Hydrocarbon Hydroxylases↗
PubMed1999

Prevalence of Meniere disease in Finland.

OBJECTIVES: To assess the prevalence of Meniere disease in the population of 5 million in Finland according to the criteria of the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) recommendation. STUDY DESIGN: Retrospective investigation based on patient records of 306 patients treated for Meniere disease and recognized as such according to the International Statistical Classification of Diseases and Related Health Problems (ICD-9 or ICD-10) in seven Finnish hospitals serving a population of 1.5 million people. METHODS: Patients were selected from the computerized patient registers of outpatients and inpatients having received an appropriate diagnosis during the period from 1992 to 1996 and re-evaluated. Definite cases according to AAO-HNS guidelines were identified to calculate the prevalence of Meniere disease in Finland at the end of 1996. RESULTS: A total of 131 definite cases of Meniere disease were identified. The prevalence of at least 43 per 100,000 and an average annual incidence of 4.3 per 100,000 were obtained. The prevalence turned out to be higher (P<.001) in Northern areas (49/100,000) than in the south (38/100,000). The prevalence did not differ in the areas of university hospitals (44/100,000) from those of central hospitals (42/100,000). CONCLUSIONS: The prevalence and incidence in Finland is lower than could be expected from previous international surveys, most of which provide inadequate data for forming a real picture of the epidemiology of Meniere disease. Uniform diagnostic criteria are indispensable for further research.

Finland↗
PubMed1999

Do we know the real need for hearing rehabilitation at the population level? Hearing impairments in the 5- to 75-year-old cross-sectional Finnish population.

The cross-sectional population sample studied here was randomly selected from the population register of northern Finland. The subjects comprised 10 different age groups between 2 and 75 years of age. Pure tone averages over the frequencies of both 0.5, 1 and 2 kHz and 0.5, 1, 2 and 4 kHz - i.e. better ear hearing levels (BEHL) of BEHL0.5-2kH and BEHL0.5-4kHz - were calculated. The prevalence of various grades of hearing impairment was investigated among the 3518 people who participated in audiometric measurements. Two different classifications were used to grade the hearing impairment. According to the World Health Organization (WHO) classification (1991), 94.3% of the subjects had normal hearing, whereas 3.8% had mild hearing impairment, 1.3% had moderate impairment, 0.4% severe impairment and 0.1% profound impairment. When the more recent EU definition (1996) was used, 85.3% of the subjects had normal hearing. Mild impairment was found in 11.5% of the subjects, moderate impairment in 2.8%, severe impairment in 0.3%, and profound in 0.1%. The difference between the two definitions mentioned above (resulting in different prevalence figures of hearing impairments) is clear. The WHO classification reveals the need for rehabilitation and can thus be used as a basis of resource allocation, whereas the EU proposal reveals even the mildest hearing impairments and hence better illustrates the real prevalence of impairment. The need for the current and future audiological services may be estimated from the prevalence rates of hearing impairments. The proportion of the Finnish elderly - the people most frequently using health services - is expected to increase from today's 15% to 23% within the next 20 years. The same phenomenon is to be expected in other Western societies.

Adolescent↗
PubMed1998

Conditions for paediatric hearing screening: a survey in 28 Finnish child welfare clinics.

The present Finnish paediatric hearing screening programme was assessed by interviewing nurses and doctors in 28 child welfare clinics responsible for the hearing screening of 18,500 preschool children. Practical issues which might have effects on both performing the screenings and referring the children with abnormal screening results were emphasised. This survey brought out a great variety of deficiencies, which may contribute to the existing delayed diagnosis of hearing impairments. Hearing screening was routinely done 4-12 times per child before school age, instead of the 3 times recommended. Methods with a nonspecific frequency range and sound pressure level were often used. Audiometers were only used in 22 of the 28 clinics, and in only 9 clinics were the audiometers calibrated yearly. The median time of working in the child health care field at that particular health centre was 7 y for the nurses and 6 y for the doctors. Both the nurses and the doctors had numerous responsibilities other than paediatric hearing screening. Implementation of an updating training programme in paediatric audiology for the personnel is recommended.

Child Health Services↗
PubMed1998

Epidemiology of A3243G, the mutation for mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes: prevalence of the mutation in an adult population.

Mitochondrial diseases are characterized by considerable clinical variability and are most often caused by mutations in mtDNA. Because of the phenotypic variability, epidemiological studies of the frequency of these disorders have been difficult to perform. We studied the prevalence of the mtDNA mutation at nucleotide 3243 in an adult population of 245,201 individuals. This mutation is the most common molecular etiology of MELAS syndrome (mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes), one of the clinical entities among the mitochondrial disorders. Patients with diabetes mellitus, sensorineural hearing impairment, epilepsy, occipital brain infarct, ophthalmoplegia, cerebral white-matter disease, basal-ganglia calcifications, hypertrophic cardiomyopathy, or ataxia were ascertained on the basis of defined clinical criteria and family-history data. A total of 615 patients were identified, and 480 samples were examined for the mutation. The mutation was found in 11 pedigrees, and its frequency was calculated to be >=16. 3/100,000 in the adult population (95% confidence interval 11.3-21. 4/100,000). The mutation had arisen in the population at least nine times, as determined by mtDNA haplotyping. Clinical evaluation of the probands revealed a syndrome that most frequently consisted of hearing impairment, cognitive decline, and short stature. The high prevalence of the common MELAS mutation in the adult population suggests that mitochondrial disorders constitute one of the largest diagnostic categories of neurogenetic diseases.

Acidosis, Lactic↗
PubMed1998

Hearing and occupation.

Not only does the environment play a role as a source of risk factors for a hearing impairment, but a hearing impairment itself can adversely affect interaction with family members, workmates and friends, thus reducing social well-being. The number of work-related hearing impairments has been decreasing for last five years, but noise-induced sensorineural hearing loss is still the second most common work-related disease in Finland. The financial burden related to occupational hearing impairments includes costs of compensation, salaries of screening personnel, equipment, maintenance costs, costs resulting from loss of work for the employer and referrals to specialist clinics etc, which until now have not been calculated in Finland. Numerous questions still remain to be answered regarding the association of age, socioacousis, occupation and leisure activities with the development of sensorineural hearing impairment. Can hearing impairment acquired in childhood or in early adolescence predict the development of occupational hearing loss? What is the interactive role of such factors as ageing, chemicals, diet, environmental noise, genetic susceptibility and the individual's other diseases in the development of noise-induced hearing impairment?

Adolescent↗