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Biomedical subjects

T Brask

Publications and source records attributed to T Brask.

14 recordsLinked to original sources
PubMed1999

Reconstruction of the ossicular chain in the middle ear with glass ionomer cement.

OBJECTIVES: The aim of this study is to describe a method to repair small defects (1 to 2 mm) of the ossicular chain by means of glass ionomer cement (GIC) alone. Larger defects can be repaired with a combination of GIC and a platinum wire prosthesis. GIC is a two-component hybrid material consisting of inorganic glass particles surrounded by an insoluble hydrogel matrix. GIC has been used by dentists for many years, but only a few reports describe the use of GIC in human middle ear surgery. Many investigators have proved that most GICs are biocompatible, biostable, and well tolerated by bone and soft tissue. STUDY DESIGN: From 1994 to 1996 GIC was used in 97 middle ear operations. In 44 cases small defects of the ossicular chain were reconstructed with GIC alone. The observation period ranged from 1 to 4 years. METHODS: Nearly all operations were performed with the patient under local analgesia. RESULTS: The postoperative air-bone gap was less than 20 dB in 83.3%. Compared with results from comparable operations, the GIC results are significantly better. One patient had reoperation because the cement had loosened from the bone as a result of faulty GIC operation technique. CONCLUSIONS: Repair of defects of the ossicular chain with GIC is an easy, efficient, quick, and inexpensive method, which ought to be kept in mind for future middle ear surgery. No complications in the middle ear were related to GIC.

Ear Ossicles↗
PubMed1993

High-frequency air conduction audiometry. Testing of a new low impedance circumaural transducer system in normal young persons.

A new circumaural transducer was tested in the frequency range 125 Hz to 20 kHz. The new transducer has a low acoustic impedance and loads the ear closely to free-field conditions, thus ensuring that sensitivity to different positions of the transducer around the ear is reduced compared to conventional audiometric headphones. The transducer was tested on 57 individuals (114 ears) in the age range 10 to 20 (median age 17.0 years). The results, showing a fairly good accordance with the ISO standard free-field thresholds values, seem to confirm that the new transducer system loads the ears similarly to free-field conditions. The results were also compared with the threshold values from other high-frequency investigations using different transducer systems. In order to verify the reliability of the system, a test-retest was carried out on 12 inexperienced normal individuals (24 ears) (median age 26.5 years; range values from 22 to 44 years). The standard deviations of the test-retest ranged from 2.8dB to 6.6dB. A comparison of these values with the results from other high-frequency test-retests is of dubious value, as such retests have often been performed and estimated in different ways. International standards for high-frequency audiometry threshold and international standards for test-retest procedure are needed. The increasing administration of cytotoxic drugs in the treatment of malignant diseases will increase the need for reliable high-frequency audiometry equipment.

Adult↗
PubMed1984

Objective venous tinnitus. A case report.

A case of objective venous tinnitus with onset just after an operation for otosclerosis is presented. The maximum intensity of the tinnitus was measured at 38 db. SPL. The tinnitus disappeared after ligation of the internal jugular vein on the affected side. It is concluded that, even if objective tinnitus is uncommon compared with subjective tinnitus, it is important to elucidate its cause, because it is sometimes possible to cure the patient.

Adult↗
PubMed1984

Benign intracranial hypertension caused by mastoiditis and lateral sinus obstruction: the value of computerized tomography in diagnosis.

A case of benign intracranial hypertension occurring in an 11-year-old boy, and due to lateral sinus obstruction, is reported. Computerized tomographic scan was conclusive, revealing a normal ventricular system and no evidence of a neoplastic lesion. Disappearance of the mastoid air cells and disruption of the trabecular pattern were also shown on the affected side. The diagnosis was confirmed at operation, and the course was favourable. In accordance with other studies cited, our findings suggest that patients suspected of benign intracranial hypertension can be spared invasive neuroradiological procedures if the computerized tomographic scan of the head is normal.

Brain↗
PubMed1984

Impedance pneumography for long-term monitoring of respiration during sleep in adult males.

Impedance pneumography is based on the relationship between respired volume (delta V) and changes of transthoracic impedance (delta/Z/) during breathing. The impedance signal, the relationship between delta V and delta/Z/ and the success rate during long-term recording was studied in 11 healthy adult males, aged 21-46, by a portable tape recorder (Oxford Medilog 4-24). The signals from the tape recorder (delta/Z/), and from a spirometer (delta V) were recorded simultaneously on a mingograph during normal breathing, apnoea, deep sighs, and coughs. The relationship between delta V and delta/Z/ was also analysed on an X-Y recorder. Delta/Z/ was delayed in relation to delta V and during one respiratory cycle the relationship was not linear. The time constant of delta/Z/ was 6 s. A significant correlation was found between peak values of delta V and delta/Z/ for 0 less than delta V less than 2.5 litres. Long-term recording of delta/Z/ during one night's sleep resulted in a success rate of 63-100%, mean 90%. Invalidation of the impedance signal was caused by overloading (81%) and interference (19%). It is concluded that the Medilog respiratory recorder enables determination of respiratory frequency, periods of apnoea and a semiquantitative estimate of volume, but artifacts may invalidate the signal.

Adult↗
PubMed1979

The noise protection effect of the stapedius reflex.

The purpose was to estimate the attenuation and protection effect of the acoustic stapedius reflex on the inner ear. The acoustic stapedius reflex was recorded by means of extratympanic manometry (ETM). This method was used, as it is able to differ between the stapedius and the tensor reflex. Patients with unilateral Bell's palsy were investigated during palsy time and after recovery. The amplitude of the contralateral acoustic stapedius reflex was used as a relative measure of the excitation of the cochlea on the affected side. The attenuation effect, 20 dB above the reflex threshold, was approximately 15 dB for all tested patients. After the ETM investigation a temporary threshold shift was shown on the affected side (average 34 dB). The hearing threshold on the healthy side was unchanged. Thus the attenuation effect of the acoustic stapedius reflex protects the inner ear from an acoustic damage. A protection effect of the tensor tympani was not demonstrated.

Audiometry↗
PubMed1978

Extratympanic manometry in man. Clinical and experimental investigations of the acoustic stapedius and tensor tympani contractions in normal subjects and in patients.

New ideas and inspirations for future human investigations have emerged from the experience obtained in this study. These investigations ought to be performed for both scientific and clinical reasons. It is the author's opinion that the ETM method is extremely useful and valuable. The author intends to continue the human investigations if proper conditions are available. The ETM equipment can also be further improved for scientific and special clinical investigations. For normal clinical practice a more "simplified" ETM equipment should be developed. Clinical investigations concerning the diagnosis of brain stem disorders and the selection of noise susceptible persons will be two of the primary clinical tasks.

Acoustic Impedance Tests↗
PubMedDate not supplied

Interpretation of sonotubometry. A critical view of the acoustical measurement of the opening of the eustachian tube.

The principle of sonotubometry for recording the opening of the Eustachian tube is based on the assumption that this opening increases the sound transmission from the nasopharynx to the external ear canal. However, the clinical validity of the method remains to be documented. In the present study the results in 37 normal ears were compared with those of 11 ears which showed signs of Eustachian tube dysfunction. In these glue was found in the middle ear at a subsequent myringotomy. In 13 of the subjects a comparison was made of the signals picked up from the ear canal and from the contralateral nostril. It was concluded that the interpretation of the signals from the ear canal is very complicated. They may be due to an opening of the Eustachian tube, but they may also be caused by a change of the acoustic conditions in the nasopharynx during the swallowing procedure. Despite the fact that this test principle in theory is ideal, much research seems to be required before the clinical value of the method can be confirmed.

Acoustics↗
PubMedDate not supplied

Ginger root against seasickness. A controlled trial on the open sea.

In a double-blind randomized placebo trial, the effect of the powdered rhizome of ginger (Zingiber officinale) was tested on seasickness. Eighty naval cadets, unaccustomed to sailing in heavy seas reported during voyages on the high seas, symptoms of seasickness every hour for 4 consecutive hours after ingestion of 1 g of the drug or placebo. Ginger root reduced the tendency to vomiting and cold sweating significantly better than placebo did (p less than 0.05). With regard to vomiting, a modified Protection Index (PI) = 72% was calculated. Remarkably fewer symptoms of nausea and vertigo were reported after ginger root ingestion, but the difference was not statistically significant. For all symptom categories, PI = 38% was calculated.

Adolescent↗
PubMedDate not supplied

Secretory otitis media--a question of surface activity in the eustachian tube?

An improved thin-layer chromatographic assay for monitoring phospholipid ratio in mucus was used to study the respiratory system distribution of children with and without secretory otitis media. Phosphatidylcholine, phosphatidylethanolamine and sphingomyelin abound, while only traces of other phospholipids are found. Analyses show more sphingomyelin and less phosphatidylcholine in the Eustachian tube and nose than in the lung, while phosphatidylethanolamine has about the same distribution. The phosphatidylcholine/sphingomyelin ratio is significantly less in Eustachian tube mucus from children with secretory otitis media compared with otologically healthy children, which indicates a different secretory pattern of the cells in the Eustachian tube of these children. The distribution of phospholipids in middle ear secretion is different from the distribution obtained from the Eustachian tube in children with secretory otitis media thus verifying a clearance 'blocking' of the tube caused by the disease.

Child↗