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Biomedical subjects

I Pyykkö

Publications and source records attributed to I Pyykkö.

At least 55 records · Page 3Linked to original sources
PubMed2000

Analysis of eustachian tube function by video endoscopy.

OBJECTIVE: Human eustachian tubes (ET) were inspected in vivo endoscopically, and video recordings were made for careful slow-motion analysis of normal physiologic function. SETTING: Ambulatory office in a tertiary referral center. SUBJECTS: Thirty-four adults, 17 with no history of ET dysfunction (2 of whom had tympanic membrane perforations), 17 with known ET dysfunction. INTERVENTIONS: Transnasal endoscopic examination of the nasopharyngeal opening of the eustachian tube during rest, swallowing, and yawning. MAIN OUTCOME MEASURES: Video analysis of ET opening movements. RESULTS: Normal ETs had four consistent sequential movements: (1) palatal elevation causing passive, then active, rotation of the medial cartilaginous lamina; (2) lateral excursion of the lateral pharyngeal wall; (3) dilation of the lumen, caused primarily by tensor veli palatini muscle movement beginning distally and inferiorly, then opening proximally and superiorly; and (4) opening of the tubal valve at the isthmus caused by dilator tubae muscle contraction. Dysfunctional ETs had intraluminal edema, polyps, or minimal muscle movement. CONCLUSIONS: Slow-motion endoscopic video analysis may be a useful new technique for the study of eustachian tube physiology. Consistent muscle movement patterns were demonstrated in normal subjects but were absent in abnormal subjects. More studies of normal and abnormal patterns are needed to establish useful clinical correlates.

Adult↗
PubMed1999

Otoneurological expert system for vertigo.

We have developed an otoneurological expert system (ONE) to aid the diagnostics of vertigo, to assist teaching and to implement a database for research. The ONE database is set to harvest data on patient history, signs and test results necessary for diagnostic work with vertiginous patients. A method based on pattern recognition was used in the reasoning process. Questions about symptoms, signs and test results are weighted and scored for each disease and the most likely disease is recognized from defined disease profiles. Missing information and uncertainties are solved with a method resembling fuzzy logic. ONE was validated by comparing diagnoses assessed by physicians with those provided by the system. It proved to be a valid decision-maker by solving 65% of the cases correctly, while the physicians' mean was 69%. To improve ONE further, a follow-up should be implemented for the patients, since diagnosing sudden deafness and Meniere's disease during the first visit is often impossible. We aim to obtain new information on diseases involving vertigo by applying adaptive computer applications, such as genetic algorithms, to the reasoning process.

Algorithms↗
PubMed1999

Smoking as a risk factor in sensory neural hearing loss among workers exposed to occupational noise.

The effect of smoking on hearing was investigated among 199 professional forest workers and 171 shipyard workers. The effect of age on hearing was corrected with Robinson's model for an audiologically screened population. The exposure of the subjects to noise and their history of tobacco smoking were examined, with special reference to blood pressure and occupational Raynaud's phenomenon. Smoking without the presence of any other risk factors did not increase the risk for sensory neural hearing loss, but smoking in combination with elevated blood pressure and occupational Raynaud's phenomenon put workers at higher risk for hearing loss than any of these factors alone.

Adult↗
PubMed1999

Effects of atropine and scopolamine on bradycardia and emetic symptoms in otoplasty.

OBJECTIVE: To assess the effects of unilateral or bilateral otoplasty on bradycardia and postoperative nausea and vomiting (PONV) and the efficiency of transdermal scopolamine in the prophylaxis of PONV. STUDY DESIGN: Post hoc assessment of the data from a double-blind, randomized study. METHODS: Fifty otoplasty patients were studied; half of them received randomly and in double-blind fashion a transdermal therapeutic system (patch) of scopolamine (TTS-scopolamine) as prophylaxis against PONV before general anesthesia. The placebo group received atropine 10 microg x kg(-1) intravenously during induction. RESULTS: The scopolamine-treated patients suffered more from moderate peroperative bradycardia (8/25; P < .05) than the atropine-treated patients (1/25). Two patients wearing a half of the TTS-scopolamine patch needed intravenous atropine. After unilateral otoplasty, none of the TTS-scopolamine-treated patients and 50% of the atropine-treated patients suffered from PONV. After bilateral operation, the respective incidences were 39% and 81% (P < .01). After unilateral otoplasty no patient needed droperidol, but after bilateral otoplasty, 12 of 19 of the atropine-treated and 4 of 18 (P < .05) of the scopolamine-treated patients needed droperidol. The mean numbers of doses of droperidol were 0.8+/-0.9 and 0.3+/-0.6 (P < .05), respectively. Two additional patients, wearing half of the TTS-scopolamine patch, suffered from mild central anticholinergic syndrome. CONCLUSION: TTS-scopolamine offers effective prophylaxis against PONV (auriculoemetic reflex), but does not protect from bradycardia (auriculocardiac reflex) in otoplasty. Cutting of the TTS-scopolamine patch may lead to undesirable side effects.

Anti-Arrhythmia Agents↗
PubMed1999

Discovering diagnostic rules from a neurotologic database with genetic algorithms.

Data on patients with Meniere's disease, vestibular schwannoma, traumatic vertigo, sudden deafness, benign paroxysmal positional vertigo, or vestibular neuritis were retrieved from the database of otoneurologic expert system ONE for the development and testing of a genetic algorithm (GA). The accuracy of the diagnostic rules in solving the test cases was 81%, 91%, 92%, 95%, 96%, and 98% for the respective diseases. The best rules retrieved from the GA were described by a set of questions with the most likely answers. The most important questions concerned the duration of hearing loss and the occurrence of head injury. The validity and structure of the rules created with a GA can be analyzed in detail. For rare diseases, some other reasoning process can be used, for example, case-based reasoning.

Algorithms↗
PubMed1999

Postural compensation after intratympanic gentamicin treatment of Menière's disease.

We have treated 93 patients with severe Menière's disease with gentamicin (GM) applied with 1 to 4 or intratympanic injections in a prospective study. The patients were tested at frequent intervals and followed up for two years. Postural stability was evaluated on posturography. Unsteadiness and gait between attacks, working capacity and vertigo were scored. Before commencing the treatment 47 of the patients complained from moderate to severe postural instability. After treatment moderate to severe postural instability was met in 19 patients. Initially the sway velocity was 27 mm/s on average being significantly worse than in referents. Two weeks after treatment the sway velocity increased to 33 mm/s. Thereafter the sway velocity slowly started to decline to 31 mm/s after two years. Patients with severe attacks of rotatory vertigo had a good postural outcome with GM treatment. In logistic regression analysis the most significant risk factor for poor recovery after GM treatment was severely reduced gait before commencing the treatment with odds ratio of 2.0. Subjectively, after two years, the patients rated their postural stability significantly improved when compared to pretreatment values. The good subjective rating of postural stability is related to postural training program where in the absence of attacks, the patients have learned to cope with daily tasks.

Adult↗
PubMed1999

Effect of intratympanic gentamicin on hearing and tinnitus in Meniere's disease.

OBJECTIVE: The objective of this study was to examine the effect of intratympanically applied gentamicin (GM) (30 mg/mL) on hearing and tinnitus in patients with intractable Meniere's disease. STUDY DESIGN: A prospective study was conducted on 93 subjects treated with intratympanically applied GM. The mean pure-tone average (PTA) at speech frequencies was measured before the treatment and after 2 weeks, 1 month, 3 months, 6 months, 1 year, and 2 years after injections. Tinnitus was surveyed with a questionnaire. The mean duration of Meniere's disease was 9.8 years (range, 1-33 years). PATIENTS: The study group consisted of 28 men and 65 women. The mean age was 50.9 years (range, 19-74 years). RESULTS: The mean PTA at speech frequencies for the group worsened from 60 dB to 68 dB, which was statistically significant. Ten ears were deafened. The mean tinnitus handicap score before treatment was 2.92; 2 years after treatment, it was 2.26, indicating significant abatement of tinnitus during the course of the treatment. CONCLUSIONS: The authors found that the average frequency of deafening was 10% and it was dose dependent. GM caused alleviation of tinnitus in the majority of the patients.

Administration, Topical↗
PubMed1999

Comparison of two head autorotation tests.

The head autorotation test is a novel method for studying the high-frequency vestibuloocular reflex without heavy machinery to generate whole-body rotation. Despite many studies with the test, the method is far from standardized, and no comparison has been made of different versions of the test. The objective of this study was to compare the vestibuloocular reflex of 100 healthy subjects measured simultaneously with two versions of the head autorotation test. Gain, phase, asymmetry, and the frequency bands reached were determined in the frequency bands of 1, 2, 3, 4, and 5 Hz. The gain measured with both tests was close to unity (range 0.95-1.04) from 1 to 4 Hz and about 0.9 at 5 Hz. In the test developed by Vorteq the phase lagged (-7 to -21 degrees) in all the frequency bands, and it differed significantly from the phase lead of 2 to 5 degrees that was measured by the other test. The asymmetry measured with the Vorteq test increased continuously from 1.5% (1 Hz) to 5.7% (5 Hz). The results of the tests showed intersubject variation, which was larger in the higher frequency bands. In conclusion, the high-frequency vestibuloocular reflex of healthy subjects can be quantified with active head oscillation. Both tests produced similar gain results, but the phase results differed systematically. Thus, the results of different head autorotation tests may not be directly comparable.

Adult↗
PubMed1999

Treatment of missing values with imputation for the analysis of otologic data.

Usefulness of imputation in the treatment of missing values in an otologic database was studied. Missing values were filled in with means (ME), regression (LR) and Expectation-Maximization (EM) imputation methods. A random imputation method (RA) provided baseline results. ME, LR and EM methods agreed on 41-42% of the imputed missing values. The level of agreement between these and RA method was 20-22%. Despite the moderate agreement, discriminant functions were similar and accurate (prediction accuracy 83-99%) for each diagnosis. A lot of data were missing in otoneurotologic tests which have less weight in the diagnosis of vertiginous patients. Consequently, the disagreement of the methods did not affect discriminant analysis. Inputation seems to be a useful method to treat missing data in this database, but future research requires more complete data and advanced imputation methods.

Data Collection↗
PubMed1999

Modelling oculomotor data with decision tree induction.

We studied relationships between oculomotor test results and the site of lesion in the data set containing patient cases with operated cerebello-pontine angle tumour, operated hemangioblastoma, infarction of cerebello-brainstem or Meniere's disease and control subjects. Several classification models were generated by decision tree induction to find parameter combinations which are efficient in classification. The studied data were characterised by missing values and scarcity of example cases. This study suggested that decision tree induction can be a useful method even in problematic real world classification tasks. Models generated by decision tree induction and evaluated by an expert physician may give information that is beneficial for research.

Brain Stem Infarctions↗
PubMed1998

One-footed and externally disturbed two-footed postural control in patients with chronic low back pain and healthy control subjects. A controlled study with follow-up.

STUDY DESIGN: A study of postural control during one-footed and externally disturbed two-footed stance among healthy control subjects and patients with chronic low back pain at the beginning of a functional back restoration program and 6 months later at follow-up examination. OBJECTIVES: To study postural control cross-sectionally among control subjects and patients with low back pain, and to evaluate the effects of functional restoration on the postural control parameters in a follow-up examination. SUMMARY OF BACKGROUND DATA: Deficits of motor skills and coordination have been reported in association with musculoskeletal disorders. It has been found that patients with chronic low back pain have impaired psychomotor control, but the impairment is reversible with successful low back rehabilitation. It is insufficiently known how functional activation and intensive physical training affect postural control. METHODS: Sixty-one healthy volunteers (32 men, 29 women) and altogether 99 patients with low back pain participated in the study. Sixty-eight patients (33 men, 35 women) had moderate and 31 (18 men, 13 women) had severe low back pain. Postural stability was measured with a force platform. In two-footed stance, vibration stimulation on calf and back muscles was used to disturb the balance. Center point of force-velocity (cm/sec), average position shift in anteroposterior direction (cm), and maximal position shift in lateral direction (cm) were used as the parameters. RESULTS: Reliability of all tests was acceptable. Center point of force-velocity was the most sensitive parameter and the one-footed measurement the most sensitivetest for evaluating postural stability. At the beginning, the patients with severe low back pain had poorer one-footed postural control compared with the control subjects (P = 0.0003). The subgroup of patients with moderate low back pain participated in the restoration program. The outcome of the restoration program was considered good if the disability because of low back pain (Oswestry index) decreased during the restoration program and poor if the disability increased or did not change. The one-footed postural stability remained primarily at the same level as the initial results in the control and good outcome groups, but became significantly poorer in the poor outcome group. The difference between poor outcome and control groups was statistically significant (P = 0.04). CONCLUSIONS: Impaired postural stability seems to be one factor in multidimensional symptomatology of patients with chronic low back trouble. Postural stability is easily disturbed in case of impairment in strength, coordination, or effective coupling of muscles in the lumbar and pelvic area. Patients with chronic low back pain seem to experience impairment in these functions, which should be taken into consideration when back rehabilitation programs are planned.

Adult↗
PubMed1998

Lyme borreliosis--an unusual cause of vertigo.

A total of 2055 consecutive vertigo patients were examined in a prospective study in an area endemic for Lyme borreliosis for clinical signs of Lyme borreliosis or serum antibodies against Borrelia burgdorferi. Of these, 41 patients (2%) had positive levels of serum antibodies against B. burgdorferi. The incidence of seropositivity against B. burgdorferi among the vertigo patients did not differ from the incidence of the normal Finnish population. In addition to seropositivity the criteria used for Lyme borreliosis included previous erythema migrans, a positive polymerase chain reaction (PCR) or positive serum immunoblot. Eight patients were diagnosed as having Lyme borreliosis. This disease is a rare but possible cause of vertigo. Seropositivity alone is an insufficient finding for the diagnosis of Lyme borreliosis and should be supported by the clinical findings, the patient's history and other laboratory findings, such as immunoblotting or PCR. Although Lyme borreliosis seems to be a rare cause of vertigo, it must be kept in mind in the differential diagnosis of vertigo.

Adult↗
PubMed1998

A head autorotation test for patients with Menière's disease.

OBJECTIVE: We compared the vestibulo-ocular reflex (VOR) of healthy volunteers and of two groups (group A, conservatively treated; and group B, with gentamicin or surgically treated) of Menière's disease (MD) patients to determine whether the head autorotation test (HART) can reveal abnormality of the VOR and whether the HART can be applied in evaluation of MD. METHODS: The gain, phase, asymmetry, and the highest frequency band reached was evaluated with the HART in the frequency range of 1-5 Hz. The caloric responses and posturography results were also determined. RESULTS: The mean gain was lower for the both groups of MD patients than for the controls. In the MD patients the phase difference was shorter and the asymmetry was greater than in the controls. Only 58% (group A) and 36% (group B) of the MD patients reached the frequency band of 4 Hz, and 33% (group A) and 19% (group B) reached 5 Hz. The respective percentages for the controls were 97 and 77%. Of the 25 MD patients (group B) 72% had abnormal HART results. Among the group A of MD patients the HART (50%) was more sensitive to VOR abnormality than the caloric test (10%) was. For aggressively treated MD patients a decrease in gain at 2 and 3 Hz in the HART correlated with abnormal caloric test results. Increased body sway in posturography correlated with the pathological results in the HART. CONCLUSION: The HART is a complementary method for evaluating the natural frequency range of the VOR, and evaluation of MD patients may benefit from combined results of the caloric test and HART.

Adult↗
PubMed1998

Changes in the vestibulo-ocular reflex: a study of elderly day hospital patients.

The vestibulo-ocular reflex (VOR) of 50 elderly day hospital patients (mean age of 82 years) was studied with the head autorotation test. Amplitude gain, phase and the highest frequency band reached were determined in the five frequency bands of 1, 2, 3, 4, and 5 Hz. Of the 50 patients, 81% had abnormal results. The gain of the elderly was significantly increased to 1.06-1.24 in the frequency bands of 3, 4, and 5 Hz in comparison with that of a control group. The elderly showed constantly a phase lead of 8-19 degrees in the frequency range of 1-4 hz and in this range differed significantly from the control group. The percentage of the elderly who reached high frequencies of head movements was reduced to 55% in the frequency band of 3 Hz and to 30% in the frequency band of 4 Hz. These findings may lead to oscillopsia and explain the high prevalence of dizziness and falls among the elderly.

Accidental Falls↗
PubMed1998

Intratympanic gentamicin in Meniere's disease.

Ninety-three patients with intractable Meniere's disease were treated with gentamicin (Garamycin 40 mg/ml) administered in 1 to 4 transtympanic injections. The patients were tested at frequent intervals and followed up for 2 years. Before treatment all subjects experienced moderate or severe handicap caused by Meniere's disease. Two years after the treatment, rotatory vertigo was abolished in 81% of subjects, Tumarkin attacks were cured in 60%, and work capacity was severely reduced in 10% and moderately reduced in 17% of subjects. The outcome of the caloric responses did not correlate with the outcome of the treatment. In logistic regression analysis poor outcome of treatment correlated with Tumarkin attacks (odds ratio 5.5), severity of vertigo (odds ratio 3.8) and gait disorders (odds ratio 2.9). The mean hearing level was significantly affected by the treatment (before, 59.1 dB HL; after, 67.9 dB HL). Ten treated ears became deafened. During follow-up 44 subjects were subjected to retreatment, usually after 6 months. Intratympanic gentamicin treatment is a relatively safe and effective way to treat Meniere's disease. The authors recommended starting with 2 injections and renewing the injections if relapse occurs.

Adult↗
PubMed1998

Paediatric facial paralysis caused by Lyme borreliosis: a prospective and retrospective analysis.

The incidence of Lyme borreliosis (LB) was studied prospectively in 49 children (< 17 years of age) with 50 episodes of acute FP. In addition, 43 children with a history of FP (average follow-up of 5.2 y) were studied retrospectively for the outcome of FP and for the symptoms and signs of late LB. In the prospective study, 17 (34%) patients with FP proved to have acute LB. They all received antibiotic treatment and their FP had a favourable outcome. In the retrospective study the patients had had FP before the diagnostic tests for LB were available. Thus, none of the 43 patients had been diagnosed to have, or treated for, LB. The outcome of their FP had generally been favourable. None of them had any signs of late LB at the follow-up visit. Our results indicate that LB is a frequent cause of acute paediatric FP in an endemic area. In addition our data suggests that FP caused by LB in children has a favourable prognosis, even when left untreated.

Acute Disease↗
PubMed1998

Surgeon's experience as a factor for emetic sequelae after middle ear surgery.

PURPOSE: To test the hypothesis that an experienced surgeon is associated with less postoperative nausea and vomiting (PONV). METHODS: A post hoc analysis was done on the data of 167 patients from 3 randomized studies on the prevention of PONV, with transdermal scopolamine, ondansetron and propofol, in middle ear surgery under general anaesthesia. RESULTS: The patients in the residents' group suffered more from PONV (69% vs. 42%, P < 0.01) and from retching or vomiting (52% vs. 23%, P < 0.001) than those in the specialists' group. The proportion of patients needing droperidol was also higher in the residents' group (66% vs. 27%, P < 0.001). The durations of anaesthesia and surgery seemed to correlate positively with PONV. In matched-pair analysis, residentship was confirmed as a risk factor for emetic symptoms. In the residents' group, prophylaxis of PONV resulted in a decrease in retching and vomiting from 71% to 29% (P < 0.01), and in patients needing droperidol from 87% to 46% (P < 0.01). CONCLUSION: The patients operated by residents need more aggressive prophylaxis for PONV than those operated by specialists in middle ear surgery.

Adult↗