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Biomedical subjects

A Axelsson

Publications and source records attributed to A Axelsson.

At least 55 records · Page 3Linked to original sources
PubMed1995

Auditory brainstem response latencies in patients with tinnitus.

Two groups of patients with annoying tinnitus were studied with brainstem response audiometry. One group comprised 56 patients with normal hearing or slight hearing loss and another of 57 patients with moderate to pronounced sensorineural hearing loss. The patients were compared with 220 controls matched regarding gender, age, and hearing loss. Two patterns of abnormalities were found. One is a prolongation of wave I accompanied by a prolongation of waves III and V, findings which are consistent with a lesion in the peripheral auditory system. The other is a lengthening of the III-V IPL, indicating a dysfunction in the brainstem. Both patterns occurred most often in tinnitus patients with normal hearing or slight hearing loss.

Adult↗
PubMed1994

Sudden sensorineural hearing loss and hemostatic mechanisms.

OBJECTIVE: To evaluate the possible causal role of pathologic hemostatic mechanisms in sudden hearing loss. DESIGN: The study was prospective. SETTING: The patients were hospitalized, and all tests were performed at the hospital. PATIENTS: Thirty-two consecutive patients with sudden hearing loss participated, as well as a control group of 28 healthy individuals. The control group was matched with regard to body mass index. MAIN OUTCOME MEASURES: Venous blood analyses were made regarding general blood parameters, as well as specific hemostatic parameters. RESULTS: Twenty-five of the patients had some kind of aberration of specific hemostasis parameters; seven patients had an increase in the activity of the plasminogen activator inhibitor 1 (ie, a glycoprotein associated with diminished fibrinolysis) compared with that in the control group (P < .05). Increased plasminogen activator inhibitor levels were most frequently observed among the patients who were overweight. Seven of the oldest patients had an increase of D-dimers, ie, a degradation product of fibrin, and most of these patients had a history of cardiovascular disease. CONCLUSION: Although isolated aberrations in the hemostatic pathway were observed, we concluded that pathologic hemostasis does not seem to have a decisive importance for the pathogenesis of sudden deafness.

Acute Disease↗
PubMed1994

Survival after cardiac arrest outside hospital over a 12-year period in Gothenburg.

BACKGROUND: A two-tiered ambulance system with a mobile coronary care unit and standard ambulance has operated in Gothenburg (population 434,000) since 1980. Mass education in cardiopulmonary resuscitation (CPR) commenced in 1985 and in 1988 semiautomatic defibrillators were introduced. AIM: To describe early and late survival after cardiac arrest outside hospital over a 12-year period. TARGET POPULATION: All patients with prehospital cardiac arrest in Gothenburg reached by mobile coronary care unit or standard ambulance between 1980 and 1992. RESULTS: The number of patients with cardiac arrest remained fairly steady over time. Among patients with witnessed ventricular fibrillation, the time to defibrillation decreased over time. The proportion of patients in whom bystander initiated CPR was increased only moderately over time. The proportion of patients given medication such as lignocaine and adrenaline successively increased. The number of patients with cardiac arrest who were discharged from hospital per year remained steady between 1981 and 1990 (20 per year), but increased during 1991 and 1992 to 41 and 31 respectively. CONCLUSIONS: Improvements in the emergency medical service in Gothenburg over a 12-year period have lead to: (1) a shortened delay time between cardiac arrest and first defibrillation and (2) an improved survival of patients with cardiac arrest outside hospital probably explained by this shortened delay time.

Adult↗
PubMed1994

Predictors of early and late survival after out-of-hospital cardiac arrest in which asystole was the first recorded arrhythmia on scene.

BACKGROUND: A large proportion of patients who suffer out-of-hospital cardiac arrest have asystole as the initial recorded arrhythmia. Since they have a poor prognosis, less attention has been paid to this group of patients. AIM: To describe a consecutive population of patients with out-of-hospital cardiac arrest with asystole as the first recorded arrhythmia and to try to define indicators for an increased chance of survival in this population. SETTING: The community of Gothenburg. PATIENTS: All patients who suffered out-of-hospital cardiac arrest during 1981 to 1992 and were reached by our emergency medical service (EMS) system and where cardiopulmonary resuscitation (CPR) was attempted. RESULTS: In all there were 3434 cardiac arrests of which 1222 (35%) showed asystole as the first recorded arrhythmia. They differed from patients with ventricular fibrillation by being younger, including more women and having a longer interval between collapse and arrival of the first ambulance. In all 90 patients (7%) were hospitalized alive and 20 (2%) could be discharged from hospital. Independent predictors for an increased chance of survival were: (a) a short interval between the collapse and arrival of the first ambulance (P < 0.001) and the time the collapse occurred (P < 0.05). Initial treatment given in some cases with adrenaline, atropine and tribonate were not associated with an increased survival. CONCLUSIONS: Of all the patients with out-of-hospital cardiac arrest, 35% were found in asystole. Of these, 7% were hospitalized alive and 2% could be discharged from hospital. Efforts should be made to improve still further the interval between collapse and arrival of the first ambulance.

Adolescent↗
PubMed1994

Protection from noise-induced hearing loss by prior exposure to a nontraumatic stimulus: role of the middle ear muscles.

Recent evidence suggests that prior exposure to a moderate-level acoustic stimulus can reduce damage due to later exposure to the same stimulus at high intensity [Canlon et al., Hear. Res. 34, 197-200 (1988)]. To test the role of the middle ear muscles (MEMs) in this phenomenon, Mongolian gerbils were conditioned by exposure to a two-octave band of noise (1414-5656 Hz) at 81 dB SPL for 3 weeks. Either immediately afterward, or following a one week rest period, they were exposed to the same stimulus at 110 dB SPL for one hour. The ABR thresholds of these animals were compared to those seen in animals exposed at 110 dB SPL without conditioning. The MEMs of one ear in each subject were cut, to determine their role in any noise trauma protection effects. In the unoperated ears, conditioning without a recovery period did not alter the effects of the 110 dB stimulus. Conditioning followed by a one week recovery period reduced both temporary (TTS) and permanent (PTS) threshold shift. MEM section had no effect on either TTS or PTS in unconditioned subjects, and did not alter the reduction in TTS or PTS seen with conditioning. It is concluded that the noise trauma resistance provided by acoustic conditioning is not mediated by the MEMs.

Acoustic Stimulation↗
PubMed1994

Survival in patients found to have ventricular fibrillation after cardiac arrest witnessed outside hospital.

Since 1980 an Emergency Medical Service (EMS) system with a two-tier ambulance service has been operating in Göteborg. During this 12-year period, all cardiac arrests outside hospital have been monitored. Cardiopulmonary resuscitation (CPR) training for the general public began in 1985 and, by the end of 1992, 125 000 persons had been trained. The aim of this study was to define the factors associated with an increased chance of survival after cardiac arrest witnessed out-of-hospital and secondary to ventricular fibrillation. The study group comprises all patients with cardiac arrest witnessed outside hospital in Göteborg between 1980 and 1992, in whom CPR was initiated by our EMS and ventricular fibrillation observed at the first ECG recording. In a multivariate analysis of age, sex, time of collapse, interval between collapse and first defibrillation, bystander-initiated CPR, the following factors were associated with an increased chance of being discharged from hospital: (1) Short interval between collapse and first defibrillation (P < 0.001); (2) Bystander-initiated CPR (P < 0.001); and (3) Age (P < 0.05). Among patients with an out-of-hospital cardiac arrest who were found by the EMS personnel to have ventricular fibrillation, the predictors of survival were: interval between collapse and defibrillation, bystander-initiated CPR and age.

Adolescent↗
PubMed1994

Risk indicators for, and symptoms associated with, death among patients hospitalized after out-of-hospital cardiac arrest.

BACKGROUND: An increasing proportion of patients who have an out-of-hospital cardiac arrest are initially successfully resuscitated and thus hospitalized. AIMS: To define risk indicators for, and to describe the mode of, in-hospital death among patients hospitalized after an out-of-hospital cardiac arrest. SETTING: Göteborg, Sweden. PATIENTS: All patients hospitalized after out-of-hospital cardiac arrest between 1980 and 1992. RESULTS: A total of 707 out of 3434 patients were hospitalized after out-of-hospital cardiac arrest, of whom 278 (39%) were discharged alive. Independent risk indicators for in-hospital death were: type of initial arrhythmia on the scene, age, interval between cardiac arrest and arrival of first ambulance, bystander-initiated cardiopulmonary resuscitation and history of diabetes mellitus. Of the patients who died in hospital, 88% had brain damage and 43% myocardial damage. CONCLUSION: Risk indicators for hospital death can be defined. The majority of in-hospital deaths were associated with brain damage.

Aged↗
PubMed1994

Effect of bystander initiated cardiopulmonary resuscitation on ventricular fibrillation and survival after witnessed cardiac arrest outside hospital.

OBJECTIVE: To describe the proportion of patients who were discharged from hospital after witnessed cardiac arrest outside hospital in relation to whether a bystander initiated cardiopulmonary resuscitation. PATIENTS: All patients with witnessed cardiac arrest outside hospital before arrival of the ambulance and in whom cardiopulmonary resuscitation was attempted by the emergency medical service in Gothenburg during 1980-92. RESULTS: Cardiopulmonary resuscitation was initiated by a bystander in 18% (303) of 1,660 cases. In this group 69% had ventricular fibrillation at first recording compared with 51% in the remaining patients (P < 0.001). Among patients in whom cardiopulmonary resuscitation had been initiated by a bystander 25% were discharged alive versus 8% of the remaining patients (P < 0.001). Independent predictors of survival were in order of significance: initial arrhythmia (P < 0.001), interval between collapse and arrival of first ambulance (P < 0.001), cardiopulmonary resuscitation initiated by a bystander (P < 0.001), and age (P < 0.01). Among patients who were admitted to hospital alive 30% of patients in whom cardiopulmonary resuscitation had been initiated by a bystander compared with 58% of remaining patients (P < 0.001) had brain damage and died in hospital. Corresponding figures for death in association with myocardial damage were 18% and 29% respectively (P < 0.01). CONCLUSIONS: Cardiopulmonary resuscitation initiated by a bystander maintains ventricular fibrillation and triples the chance of surviving a cardiac arrest outside hospital. Furthermore, it seems to protect against death in association with brain damage as well as with myocardial damage.

Age Factors↗
PubMed1994

Hearing in 18-year-old Swedish males.

In modern work practice, occupational noise exposure appears to be diminishing. Conversely, leisure noise activities appear to increase exposure to both the occurrence and the level of sound. If increased exposure to noise results in deteriorating hearing, one would expect to discover this by audiometric tests in teenagers. In the present investigation, 500 randomly selected conscripts from military service were tested. The mean hearing level was mostly well within that expected by international standards. The individual analyses show that 14% had some hearing loss defined as more than 20 dBHL in either ear and in the frequency range 0.25-8 kHz. This figure is considerably lower than recent reports from Norway and Great Britain. We did not find any correlation between different health parameters and hearing loss, except that conscripts of short stature tended to have more hearing loss. Consequently, we could not confirm an increasing general prevalence of hearing loss in young male individuals.

Adolescent↗
PubMed1993

Miniature microphone probe tube measurements in the external auditory canal.

The use of a miniature microphone probe tube for sound-pressure level measurements in the outer earcanal was studied in four experiments. The main reason was to evaluate this method for clinical applications and for measurements of hearing protector attenuation. All measurements were registered in 1/3-oct bands. The dynamic range, frequency response of the microphone system, the insertion loss of the probe tube walls, and the influence of the probe tube in the ear canal on the sound-pressure level were examined. The first experiment attempted to determine an optimal placement of the probe tube in the earcanal. Sound-pressure levels resulting from a known free-field sound stimulus were measured at 12 different positions in the earcanal of human subjects. The results indicated that the position which is least sensitive for small movements of the probe tube on the measure was within 1 to 3 mm of the tympanic membrane. In a second experiment the changes in sound transfer function to the tympanic membrane caused by the microphone itself, when positioned just outside the ear canal entrance, were studied for 72 angles of sound incidences in ten subjects. A few minor but significant changes were observed with the microphone in this position. In a third experiment, sound transfer functions were measured from free sound field to the tympanic membrane in 19 subjects. The measurements were performed in 1/3-oct frequency bands (0.2 to 20 kHz) with sound incidences from 24 azimuthal positions and for each of these, three different elevations. The inter- and intrasubject-variability are analyzed and discussed. Finally, the reliability of probe tube microphone measurements was evaluated by repeated measurements of the sound transfer function, five times in ten subjects with the sound incidence from one position. The results indicated very small variations between repeated measurements.

Acoustic Stimulation↗
PubMed1993

Structure of perceived handicap in middle-aged males with noise-induced hearing loss, with and without tinnitus.

By using a modified stepwise regression analysis technique, the structure of self-perceived handicap and tinnitus annoyance in 89 males with noise-induced hearing loss was described. Handicap was related to three clusters of variables, reflecting individual, environmental, and socioeconomic aspects, and 60% of the variance in self-perceived handicap was explained by the representatives of these clusters: i.e. 'acceptance of hearing problems', 'social support related to tinnitus' and 'years of education'. Tinnitus had no impact of its own on self-perceived handicap and only a modest portion (36%) of the variance in tinnitus annoyance was explained by 'sleep disturbance' and 'auditory perceptual difficulties'.

Adaptation, Psychological↗
PubMed1993

The sound world of the child. The relationship between daily activities and hearing acuity.

A group of 50 first, fourth and sixth grade children provided diaries of their activities each hour of the day for 12 consecutive weeks. These activities were correlated with their auditory thresholds assessed at two different times during the behavioral recording period. The results indicated that these schoolchildren experience relatively little noise exposure during their normal daily activities. Further, the incidence of noisy activities was not closely related to hearing thresholds. Other behaviors that are relatively quiet, such as watching television, however, were predictive of higher auditory thresholds.

Audiometry↗
PubMed1992

Effect of low level acoustic stimulation on temporary threshold shift in young humans.

To assess the effect of a low level acoustic stimulation on the susceptibility to noise, young human subjects were exposed to music at 70 dBA for 6 h per day during 9 days (training period). Noise sensitivity was assessed by measuring temporary threshold shift (TTS) induced by 105 dBSPL, 1/3 octave band noise at 2 kHz for 10 min. On the fifth day of the training period, a significant decrease of TTS was observed in the frequency range 3-3.5 kHz, in comparison with the baseline TTS obtained before being trained. As the training continued, the frequency range which showed a significant reduction of TTS expanded to 2-5 kHz.

Acoustic Stimulation↗
PubMed1992

The development of melanin in the stria vascularis of the gerbil.

One factor that influences noise susceptibility is pigmentation. The aim of this study was to investigate the development of melanocytes, other melanin-containing cells and the amount of melanin in stria vascularis from birth to adult age in the gerbil which has a uniform pigmentation of the fur and eyes, is born without hearing but establishes hearing function at 14-18 days after birth. Changes in the melanin morphology, concentration and distribution have been correlated to the development of the inner ear and to the time period during which hearing function is established, which indicates that the melanocytes in stria vascularis are of importance for the hearing function.

Age Factors↗
PubMed1992

The interaction of smoking and noise on temporary threshold shifts.

Four separate experiments examined the effects of cigarette smoking on temporary threshold shifts (TTS) following noise exposure. One experiment compared smokers and non-smokers after the subjects had abstained from smoking for at least 6 h. A second experiment tested only smokers who smoked a cigarette just before noise exposure, during the noise exposure and in a control condition during which they did not smoke. A third experiment tested only non-smokers who were exposed to noise after chewing nicotine gum or after a control condition in which they rested without chewing the gum. A fourth experiment tested smokers and non-smokers in one condition which required them to smoke a cigarette just prior to noise exposure and in another condition which prevented them from smoking. The results indicate that smokers consistently evidence slightly smaller TTS than do non-smokers. Non-smokers evidenced significantly greater TTS at one frequency after they had chewed nicotine gum than when they had not. These results suggest that the smaller TTS associated with cigarette smoking is related to both the chronic and the acute effects of smoking and that these effects may be more attributable to carbon monoxide than to nicotine.

Adolescent↗
PubMed1992

Psychological and audiological correlates of perceived tinnitus severity.

Beliefs and attitudes towards tinnitus have been found to play an important role in the process of rehabilitation. The relationship between audiological, psychological and psychosomatic factors (self-assessment of vertigo and headache and the perceived severity of tinnitus) was investigated in a clinical population of 163 subjects. Audiological descriptives comprised pure-tone average (dB HL), etiology of hearing loss, duration of tinnitus and tinnitus localisation. Perceived severity of tinnitus was assessed with a questionnaire focusing on tinnitus impact on aspects of quality of life, concentration and sleep. A 28-item handicap and support questionnaire was used and factor analysed, resulting in three factors: perceived attitudes, social support and disability/handicap. Tinnitus severity was significantly related to perceived attitudes. The influence of social support on tinnitus severity did not seem to be crucial. The results showed that significantly more women than men complained about vertigo. Unilateral tinnitus localisation was also more prevalent in females. The subjects with multiple tinnitus localisations were older and had significantly more sleep disturbance than subjects with tinnitus localized to the ears only. In accordance with previously reported observations, the frequency of headaches was strongly correlated with the severity of tinnitus.

Adaptation, Psychological↗
PubMed1992

Acupuncture for tinnitus management.

Fifty-six patients with continuous and severe tinnitus as their major complaint were treated with traditional Chinese acupuncture. After a pre-treatment period with baseline evaluation of tinnitus, 10 treatments were given during a period of 20 days, followed by a post-treatment period in order to obtain indications of prolonged treatment effects. Assessments were made using visual analogue scales (VAS) and a verbal retrospective rating scale. Three patients reported improvement which lasted for at least 10 days after the last treatment, indicating a possible long-term effect in some cases. Twenty-one percent of the patients reported transient intensity reductions lasting for hours/days. Estimated 'substantial' improvement rate by VAS, consistent for all three parameters involved (intensity, annoyance, awareness), was 20%, while the corresponding deterioration rate was 25%. Statistical analysis of the whole group did not show any significant general treatment effects. Interactions between treatment evaluations by verbal rating and VAS are discussed as well as interactions with psychological components.

Acupuncture Points↗