Search PubMed⌕ Search

Biomedical subjects

E Kentala

Publications and source records attributed to E Kentala.

At least 19 recordsLinked to original sources
PubMed2006

Assessing the depth of dexmedetomidine-induced sedation with electroencephalogram (EEG)-based spectral entropy.

BACKGROUND: Adequate sedation of critically ill patients improves the outcome of intensive care. Maintaining an optimal level of sedation in the intensive care unit (ICU) is difficult because of a lack of appropriate monitoring methods to guide drug dosing. Dexmedetomidine, a selective alpha(2)-adrenoceptor agonist, has recently been introduced for the sedation of ICU patients. This study investigated the utility of electroencephalogram (EEG)-based spectral entropy monitoring (with M-ENTROPY, GE Healthcare, Helsinki, Finland) for the assessment of dexmedetomidine-induced sedation. METHODS: Eleven healthy, non-smoking men, aged 23.9 +/- 2.5 years (mean +/- standard deviation), were recruited. Spectral entropy was recorded before and during low (0.5 ng/ml) and high (5 ng/ml) plasma concentrations of dexmedetomidine. At the end of the infusion, subjects were awakened by verbal command and light shaking. RESULTS: Spectral entropy decreased from 84 +/- 5 to 66 +/- 16 (P= 0.029) during low dexmedetomidine levels and from 84 +/- 5 to 20 +/- 12 (P < 0.001) during high dexmedetomidine levels. Transitions during loss and regaining of consciousness were analysed separately. Entropy decreased from 76 +/- 8 before to 43 +/- 10 (P < 0.001) after loss of consciousness, and increased from 14 +/- 4 to 63 +/- 13 (P < 0.001) on regaining of consciousness. These changes were consistent across all subjects. Prediction probability and sensitivity values indicated a high predictive performance of the method. CONCLUSION: The depth of dexmedetomidine-induced sedation can be monitored with EEG-based spectral entropy. These results should be confirmed in a clinical setting.

Adult↗
PubMed2006

Value of imaging studies in vertiginous children.

OBJECTIVE: Imaging of the head is expensive and can be stressful for children, some of whom need anesthesia for the procedure. The aim of this study was to determine which vertiginous children benefit most from head imaging. METHODS: We conducted a retrospective chart review of all children aged under 18 years who were referred to the Helsinki University Children's Hospital Radiology Department (tertiary referral center) for head computerized tomography (CT) or magnetic resonance imaging (MRI) over a 1-year period. We analyzed and reviewed the medical records of 87 children who had undergone imaging of the head due to vertigo. RESULTS: Altogether 978 children underwent imaging of the head for various indications. Of these, 87 aged 0-16 years (mean age 8 years) were imaged because of vertigo. Abnormalities were seen in the images of 37 children; 23 were new findings and 14 showed no change in comparison to earlier deviant images. The most common abnormalities in head imaging were brain tumors, infections, multiple sclerosis lesions, and other lesions in T2-weighted images. Of the 23 vertiginous children with a new finding, 19 also had neurological deficits. While four children had no neurological symptoms, three had intense headaches. CONCLUSIONS: Head imaging is necessary for vertiginous children with neurological deficits or persistent headaches or who have sustained a head trauma. If vertigo is the only symptom without trauma, imaging studies will not aid diagnostic work-up.

Adolescent↗
PubMed2005

Control of sway using vibrotactile feedback of body tilt in patients with moderate and severe postural control deficits.

We evaluated the effect of the vibrotactile display of body tilt upon the postural stability of vestibulopathic subjects during standing. Two groups were studied: those with moderate and with severe deficits as defined by postural stability test scores. They were studied under conditions of distorted sensory input, and during anterior-posterior perturbations. Seventeen subjects, with uni- or bilateral vestibular deficits, as determined by electronystagmography and vertical axis rotation, were tested using Equitest computerized dynamic posturography (CDP). Based on their performance on the CDP they were divided into two groups having either moderate (nine subjects) or severe (eight subjects) postural control deficits. Their anterior-posterior (A/P) body motion at the waist was measured with a micromechanical rate gyroscope and a linear accelerometer. The resulting tilt estimate was displayed by a vibrotactile array attached to the torso. The vibration served as a tilt feedback to the subject. The subject's performance was evaluated using the root-mean-square (RMS) of both the A/P body motion and center-of-pressure (CoP) estimates. Sensory distortions were introduced using the Equitest Sensory Organization Tests (SOT). These tests are designed to distort A/P sensory inputs while standing. The SOT 5 distorts proprioceptive information about ankle joint movement, while the subject stands eyes-closed on a moving support platform that measures foot pressure. The SOT 6 adds distorted visual information about body movement instead of testing with eyes closed. Perturbations were introduced using the Equitest Motor Control Tests (MCT). These move the support platform forward or backward with small, medium and large displacements in the horizontal plane while measuring subjects' foot pressure responses. We used the medium and large backward tests. Vibrotactile display of body tilt reduced the subjects' A/P sway and improved their balance. The finding was more evident for those subjects with severe deficits than those moderate ones. This trend was found for both SOT 5 and 6, as well as the medium and large MCT. Additionally, during the MCT, the peak deflection and mean recovery time also decreased significantly.

Adaptation, Physiological↗
PubMed2004

Postural instability in Meniere's disease.

In order to characterize the postural instability by duration of Meniere's disease (MD) we present the results of 180 MD patients tested on posturography. The duration of the disease varied from 4 weeks to 36 years. The patients were clinically examined and they had filled a questionnaire concerning their symptoms. Postural instability was examined by a force platform posturography and the results are expressed as sway velocities (SV). There was no statistically significant difference in the mean SV between groups of different duration of MD. The number of the patients with normal eyes open SV declined by duration of the illness from 73% to 38% but the decline was not statistically significant. The mean age in the different duration groups of MD varied from 47 to 61 years. In general 58% of the patients had their eyes open SV in normal range and 55% when measured eyes closed. When examining the SV between the 4 different hearing stages of MD we found that those belonging into the group III (pure tone average [PTA] 41-70 dB) had significantly higher eyes open and eyes closed SV's than the patients in the group I (PTA under 25 dB).

Adult↗
PubMed2003

Vestibular dysfunction in adult patients with osteogenesis imperfecta.

Progressive hearing loss is a major symptom in osteogenesis imperfecta (OI), a genetic brittle bone disease. Vertigo is frequently associated with otosclerosis in which the hearing loss clinically resembles that in OI. Vertigo is also common in basilar impression (BI) found in up to 25% of adult OI patients. In order to evaluate the cause, frequency, and characteristics of vertigo in OI, 42 patients were studied by interview, clinical examination, and audiological examination supplemented with electronystagmography (ENG) and lateral skull radiography. Audiometry showed hearing loss in 25 patients (59.5%). Nine patients (21%) displayed abnormal skull base anatomy in the forms of basilar impression, basilar invagination, or both, all designated here as BI. Twenty-two patients (52.4%) reported vertigo, mostly of floating or rotational sensation of short duration. Patients with hearing loss tended to have more vertigo than patients with normal hearing. Vertigo was not correlated with type of hearing loss or auditory brain-stem response (ABR) pathology. ENG was abnormal in 14 patients (33.3%). No dependency was found between vertigo and deviant ENG results. Patients with BI tended to have more vertigo than patients with normal skull base but the difference was not statistically significant. Neither ENG pathology, nor the presence or type of hearing loss showed correlation with BI. In conclusion, vertigo is common in patients with OI. In most cases, it may be secondary to inner ear pathology, and in only some patients does BI explain it. Since some OI patients without BI or hearing loss also suffer from vertigo, further clinical and neurological studies are needed to define the pathogenesis of vertigo in OI.

Adult↗
PubMed2003

Instantaneous beat-to-beat variability reflects vagal tone during hyperbaric hyperoxia.

Hyperbaric hyperoxia affects heart rate variability (HRV) by increasing parasympathetic activity. The purpose of this study was to evaluate the applicability of instantaneous beat-to-beat variability (SD1 of Poincaré plot analysis) in detecting changes in vagal tone and to evaluate possible changes in the fractality of heart rate dynamics (alpha1 of detrended fluctuation analysis) during hyperbaric hyperoxia. Continuous three-lead ECG recordings were taken in ten divers who were treated at 2.5 ATA with air (PO2 47 kPa) and oxygen (PO2 235 kPa) for 60 min. Power spectral analysis, Poincaré plot analysis and alpha1 were analyzed before compression, after 30 min and after 55 min at 2.5 ATA. Correlations between the variables were calculated after 55 min exposure. SD1 and high frequency (HF) power increased significantly but alpha1 decreased during hyperbaric hyperoxia (PO2 235 kPa). HF power and SD1 also correlated significantly. However, HF power and SD1 correlated inversely with alpha1. During hyperbaric hyperoxia, SD1 reflects vagal activity and can be used instead of HF power, if stationary conditions cannot be achieved. The decreasing alpha1 indicates more random heart rate dynamics during hyperbaric hyperoxia.

Diving↗
PubMed2002

Hearing loss and tinnitus in Meniere's disease.

OBJECTIVES: To characterize hearing loss, tinnitus and associative factors in Meniere's disease. METHODS: From our vertigo database consisting of 1356 patients, we retrieved 243 patients with Meniere's disease (MD). RESULTS: Hearing loss was the initial symptom in 13% of cases. Altogether 64% (n=133) of the patients stated that their hearing was reduced during the vertigo attack. The hearing deteriorated more likely during the vertigo attack if the vertigo attack was very intense [r(206)=0.19]. Tinnitus was the initial symptom in 5% of cases. The tinnitus was mild in 38% (n=90), moderate in 32% (n=76) and severe in 30% (n=72) of patients. The intensity of tinnitus correlated with the occurrence of drop attacks [r(237)=0.29], vertigo provoked by head positioning [r(235)=0.25], by physical activity [r(230)=0.33], or by pressure changes [r(239)=0.27]. CONCLUSION: Prolonged disease causes deterioration of hearing. Intense tinnitus is common in MD and is more often seen in late stage of the disease.

Adolescent↗
PubMed2001

Clinical picture of vestibular schwannoma.

PURPOSE: To characterize the clinical picture with vestibular schwannoma, we retrieved 122 patients with vestibular schwannoma from the vestibular unit of the Helsinki University Central Hospital. PROCEDURES: The patients filled out a questionnaire concerning their symptoms, earlier diseases, accidents, and the use of tobacco and alcohol. This information was then completed with results of audiometric, neurotologic and imaging studies. The data were prospectively stored to the database of neurotologic expert system called ONE. RESULTS: The average tumor size was 21 mm. Most of the patients had hearing loss (94%) and tinnitus (83%) but only half of them (49%) had vertigo attacks. The most common initial symptom was hearing loss combined with tinnitus (34%, n=44). Vertigo only was the initial symptom for 12 patients. The mean duration of a vertigo attack was from 5 min to 4 h and the intensity of the attack was regularly mild (37%) or moderate (32%). The vertigo of the vestibular schwannoma patients differed from vertigo in other diseases by the absence (63%) or low intensity (18%) of nausea. Spontaneous nystagmus was present in 56 patients (46%), and caloric asymmetry (>25%) was observed in 66% (n=69). Caloric asymmetry increased with tumor size. The prevalence of headache was 18% (n=21). Sudden slips seldom (7%) occurred. CONCLUSION: Hearing loss and tinnitus are the main symptoms of vestibular schwannoma. Only half of patients have vertigo. Screening to detect vestibular schwannoma is more yielding in sudden deafness patients rather than in patients with Meniere's disease.

Caloric Tests↗
PubMed2001

Stimulated expression of cyclooxygenase-2 in porcine heart after bypass circulation and cardioplegic arrest.

OBJECTIVES: Cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) enzymes catalyze the initial step in the formation of prostaglandins, which have a role in the regulation of circulation and in inflammatory reactions. As hypoxia is reported to stimulate the expression of COX-2, we have investigated the effects of bypass circulation and cardioplegic arrest on the expression COX-1 and COX-2 in the myocardium of porcine hearts. METHODS: Anaesthetized pigs were connected to cardiopulmonary bypass and the hearts were arrested by cold crystalloid cardioplegia for 30 min and reperfused thereafter for 90 min. Then the mRNA and protein levels of COX-1 and COX-2 were measured from the transmural specimens of the left ventricular myocardium by Northern and Western blot analyses. Reference specimens were from the hearts of unoperated control pigs and from sham-operated pigs, which were connected to cardiopulmonary bypass for 120 min without any aortic clamping. RESULTS: COX-1 mRNA was expressed in unoperated control porcine hearts, whereas the expression of COX-2 mRNA was weak in control hearts. The expression of COX-2 mRNA increased to 170% of the control level in the hearts of sham-operated pigs and to 180% in arrested hearts, while the level of COX-1 mRNA was not changed. Both COX-1 and COX-2 proteins were detected by Western blot analysis in the myocardial specimens of control hearts. After cardioplegic arrest, the level of COX-2 protein increased to 280% of the control level in arrested hearts, whereas the level of COX-1 protein remained unchanged. CONCLUSIONS: These results indicate that the expression of the COX-2 gene is stimulated in the ventricular myocardium of the porcine heart after bypass circulation and cardioplegic arrest.

Animals↗
PubMed2001

Short-lasting drop attacks in Meniere's disease.

OBJECTIVES: To study the vertigo attacks known as Tumarkin attacks or drop attacks (DA). DA are characterized by sudden loss of balance with or without falls but with preserved consciousness, and they are supposedly triggered by changes in the otolith function of Meniere's disease (MD). STUDY DESIGN AND SETTING: Data from 243 consecutive MD patients were collected into a database of an otoneurologic expert system. RESULTS: DA was experienced by 72% (n = 173) of the patients with MD. It correlated with visually provoked vertigo. Gait difficulties, tinnitus, and anxiety were more common in the DA group. Long lasting vertigo attacks were more frequently provoked in the DA subjects by physical strain (58% vs 14%), head movements or changes in head position (71% vs 48%), pressure changes (54% vs 12%), or rapid movements in visual surroundings (65% vs 35%) than in the non-DA subjects. CONCLUSION: DA are common in MD patients. The abrupt occurrence of DA make them poorly tolerated. SIGNIFICANCE: DA are more common in advanced MD.

Accidental Falls↗
PubMed2001

Classification of patients on the basis of otoneurological data by using Kohonen networks.

Machine learning methods such as neural networks, decision trees and genetic algorithms can be useful to aid in the classification of patients. We tested Kohonen artificial neural networks, which are known to be effective for classification tasks. Our sample included patients with six different diseases. The Kohonen network algorithm recognized the four largest groups reliably, but the two smallest groups were too small for the method. Neural networks seem to be promising for the computer-aided classification of otoneurological patients provided that the number of patients used is sufficiently large.

Algorithms↗
PubMed2001

Application of artificial intelligence in audiology.

In this paper, machine learning methods based on artificial intelligence theory are applied to the computer-aided decision making of some otoneurological diseases, for example Ménière's disease. Three methods explored are decision trees, genetic algorithms and neural networks. By using such a machine learning method, the decision-making program is trained with a representative training set of cases and tested with another set. The machine learning methods are useful also for our otoneurological expert system, One, which is based on a pattern recognition approach. The methods are able to differentiate most of the cases tested between the six diseases included, provided that a sufficiently large training set is available.

Algorithms↗
PubMed2001

On classification capability of neural networks: a case study with otoneurological data.

We investigated the capability of multilayer perceptron neural networks and Kohonen neural networks to recognize difficult otoneurological diseases from each other. We found that they are efficient methods, but the distribution of a learning set should be rather uniform. Also it is important that the number of learning cases is sufficient. If the two mentioned conditions are satisfied, these neural networks are similarly efficient as some other machine learning methods. The conditions are known in the theory of neural networks [1,2], but not often taken seriously in practice. Both networks functioned as well, excluding the case with several input variables, where the Kohonen neural networks surpassed the perceptron.

Algorithms↗
PubMed2000

Usefulness of imputation for the analysis of incomplete otoneurologic data.

The usefulness of imputation in the treatment of missing values of an otoneurologic database for the discriminant analysis was evaluated on the basis of the agreement of imputed values and the analysis results. The data consisted of six patient groups with vertigo (N=564). There were 38 variables and 11% of the data was missing. Missing values were filled in with the means, regression and Expectation-Maximisation (EM) imputation methods and a random imputation method provided the baseline results. Means, regression and EM methods agreed on 41-42% of the imputed missing values. The level of agreement between these and the random method was 20-22%. Despite the moderate agreement between the means, regression and EM methods, the discriminant functions were similar and accurate (prediction accuracy 83-99%). The discriminant functions obtained from the randomly imputed data were also accurate having prediction accuracy 88-97%. Imputation seems to be a useful method for treating the missing data in this database. However, a lot of data was missing in otoneurologic tests, which are likely to be of less importance in the diagnosis of vertiginous patients. Consequently, the disagreement of the methods did not affect clearly the discriminant analysis, and, therefore, future research requires more complete data and advanced imputation methods.

Data Collection↗
PubMed2000

Epidural infusion of bupivacaine and fentanyl reduces perioperative myocardial ischaemia in elderly patients with hip fracture--a randomized controlled trial.

BACKGROUND: Perioperative myocardial ischaemia is an important risk factor for cardiac morbidity and mortality after noncardiac surgery. The impact of analgesic management on the incidence and severity of cardiac ischemia was studied in 77 elderly patients undergoing surgical treatment of traumatic hip fracture. METHODS: After hospital admission and written consent, patients were randomised to conventional analgesic regimen (intramuscular oxycodone, OPI group) or continuous epidural infusion of bupivacaine/fentanyl (EPI group). The analgesic regimens were started preoperatively. Patients were operated under spinal anaesthesia and the treatments were continued three days postoperatively. ECG was continuously recorded. ST segment depression of > or = 0.1 mV or elevation of > or = 0.2 mV lasting > or = 1 min were considered as ischaemic episodes. Nocturnal arterial oxygen saturation (SaO2) was recorded perioperatively, and subjective pain was assessed every morning using a visual analogue scale (VAS). RESULTS: Fifty-nine (OPI 30, EPI 29) patients were evaluable for efficacy. Thirteen patients (43%) in the OPI and 12 patients (41%) in the EPI group had ischaemic episodes (NS). However, significantly more patients in the OPI group had ischaemic episodes during the surgery (8 vs. 0 in the EPI group, P=0.005). The median (quartal deviation) total ischaemic burden (i.e. integral of ST-change vs. time) in patients with ischaemic episodes was ten times larger in the OPI group (340 [342] mm x min) compared with the EPI group (30 [36] mm x min) (P=0.002). There were no significant differences between the groups in average heart rates or in heart rates at the start of ischaemic episodes or in maximal heart rates during the attacks. Average nocturnal SaO2 was similar in the two groups and there were no differences in the number of hypoxaemic (SaO2<90%) episodes. Preoperatively there were no differences in subjective pain, but postoperative and average perioperative VAS scores for pain were almost 40% lower in the EPI group (P=0.006). Perioperative myocardial infarctions were not detected. CONCLUSIONS: Continuous epidural bupivacaine/fentanyl analgesic regimen, started preoperatively, reduces the amount of myocardial ischaemia in elderly patients with hip fracture.

Aged↗
PubMed2000

Hyperbaric oxygen increases parasympathetic activity in professional divers.

The role of autonomic nervous system in hyperoxic bradycardia was evaluated by using the power-spectral analysis of heart-rate variability (HRV). Ten professional divers went through two hyperbaric hyperoxic experiments: (1) hyperbaric oxygen (HBO), 100% oxygen at 2.5 ATA, (2) hyperbaric air (HBAIR), O(2) 21% at 2.5 ATA. Four-minute traces of ECG were registered and subjected to power-spectral analysis. Cardiac conduction parameters were evaluated by a diagnostic 12-lead ECG and arrhythmias by a continuous 3-lead ECG. Statistical analysis was made using analysis of variance for repeated measurements. Heart rate decreased (P < 0. 001), but the response was similar during both treatments (P=0.14). Total power increased significantly more during HBO than HBAIR (P=0.003). High-frequency (HF) power (P < 0.001), Hayano's index (P=0.001) and normalized units of HF power (P=0.002) increased and LF/HF index (P < 0.001) decreased more during HBO than HBAIR. There were no changes in cardiac conduction or incidence of arrhythmias. In conclusion, 100% oxygen at 2.5 ATA caused marked increase in parasympathetic tone compared with 21% oxygen at 2.5 ATA.

Analysis of Variance↗
PubMed2000

Vestibular schwannoma mimicking Ménière's disease.

We retrieved information on 128 patients with vestibular schwannoma (VS) and 243 patients with Ménière's disease (MD) from the database of the otoneurologic expert system (ONE). The patients filled in a questionnaire concerning their symptoms, earlier diseases, accidents and tobacco and alcohol use. This information was then integrated with results of audiometric, otoneurologic and imaging studies. Forty-nine (38%) of the VS patients had the full triad of vertigo, hearing loss and tinnitus. The vertigo mimicked that in MD in 18 (14%) patients. The mean age of these patients was 48 years. There were 7 men and 11 women. The tumour was small (< 2 cm) in eight patients and medium-sized (2-4 cm) in seven patients. The mean attack duration in these 18 patients ranged from 5 min to 4 h. The attacks most commonly (69%) occurred only once or twice a year. Their intensity was moderate. Half of the patients had spontaneous nystagmus. Caloric asymmetry > 25% was detected in 61% of the patients. Tinnitus in these patients was mostly (49%) mild. Intense tinnitus was present only in 12% of patients. Headache was present in 25% of these patients.

Adolescent↗