PubMed Health⌕ Search

Biomedical subjects

A Salmivalli

Publications and source records attributed to A Salmivalli.

At least 19 recordsLinked to original sources
PubMed1995

Objective real ear measurements of bone-conduction hearing aid performance.

Conventional bone-conduction and bone-anchored hearing aids are tested with skull simulator devices; individual adjustments are reliant on psychoacoustic free-field audiometry, which can be quite demanding for the patient. A method is presented in which the induced skull vibrations are measured with an accelerometer and then analysed with Fast Fourier Transformation (FFT). With this method, frequency characteristics, harmonic distortion and dynamic response can be analysed.

Bone Conduction↗
PubMed1990

The effects of hypoxic hypoxia on brain stem mediated stapedial reflex in healthy volunteers.

The stapedial reflex is routinely used both in hearing evaluation and to distinguish cochlear from retrocochlear lesions. The present study was carried out on seven healthy volunteers in the hope of obtaining basic information about the physiological variables of stapedial reflex using hypoxic hypoxia. The results show that a short-term hypoxic hypoxia affects, for the most part, the muscle contraction velocity and the amplitude of the reflex, whereas the latency remains unchanged. This finding indicates that the arterial O2-saturation may have an influence when studying the effects of breathing depressive drugs or in patients with decreased ventilation capacity.

Adult↗
PubMed1990

Speech recognition in a noisy and reverberant environment with and without earmuffs.

The effect of earmuffs on speech recognition in conditions comparable to an actual environment was studied with the use of sentences, words and nonwords. The speech level was adjusted to 60 and 85 dBA. White noise was used at signal-to-noise ratios (S/N) of 0, +5, and +10 dB. The reverberation times were 2.1 and 1.6 s. In quiet conditions at normal speech level (60 dBA), the perception was better without earmuffs than with them. At a high noise level, equal or better scores were achieved with ear protectors. At high speech and noise levels (85 dBA, S/N 0), the benefit of earmuffs was clearly demonstrated. Also with longer reverberation, the use of ear protectors increased the perception scores, especially at high speech and noise levels.

Acoustics↗
PubMed1990

Effect of noise on word discrimination by subjects with impaired hearing, compared with those with normal hearing.

A comparison was made of the discrimination ability of different groups of hearing-impaired and normal-hearing subjects in noisy conditions. Four groups of subjects having a sensorineural hearing loss with various audiogram configurations, one group of subjects having a conductive hearing loss and one group of normal-hearing subjects were chosen. The submaster tapes were recorded in quiet and in pink noise with signal-to-noise ratios of -3, -8, and -13 dB. The test subjects heard the test words monaurally via earphones. The best speech discrimination was achieved in quiet, anechoic conditions. As the noise level increased, speech discrimination decreased. Subjects with sensorineural hearing loss were more adversely affected by noise than subjects with normal hearing or with conductive hearing loss. However, at high noise levels, their speech discrimination was poorer than that of normal-hearing subjects. Persons with a high-frequency hearing loss, cut-off point 1 kHz, suffered in noise similarly to those with sloping or flat hearing losses. In quiet and in moderate noise, the speech discrimination of subjects with a conductive hearing loss and subjects with normal hearing was similar, while at high noise levels, subjects with conductive hearing losses achieved better discrimination than normal-hearing subjects.

Adolescent↗
PubMed1990

Recognition of low-pass filtered words in a noisy and reverberant environment with and without earmuffs.

The effect of earmuffs on the recognition of low-pass filtered Finnish speech test material was investigated by presenting both the unfiltered and filtered words at two speech levels, 60 dB(A) and 85 dB(A) to a group of students with normal hearing. The background noise level (quiet, S/N +10, +5, 0 dB) and reverberation time (2.1 s and 1.6 s) were altered in a multi-purpose hall. Unfiltered words were recognized better without earmuffs in quiet conditions and at S/N +10 and +5 dB. At S/N 0 dB, however, better scores were obtained when earmuffs were used. Filtered words were recognized significantly better without earmuffs at both reverberation times and at all S/N conditions tested. The decrease in the reverberation time improved all the recognition scores essentially.

Adolescent↗
PubMed1984

Stapedius reflex and brainstem auditory evoked responses in multiple sclerosis patients.

The stapedius reflex (SR), its adaptation and the brainstem auditory evoked potential (ABR) were recorded in a group of 53 multiple sclerosis patients. All cases were classified as definite according to Schumacher's criteria, and their grade of disability in Hyllested's system was 1-4: no cases of the gravest (grades 5 and 6) disability were included in the series. The peripheral hearing (pure-tone audiogram and speech threshold) was normal in 44 and slightly impaired in 8 cases. SR was abnormal in 6 (11%) and borderline in 11 (21%), whereas the ABR was considered abnormal in 21 (40%) patients. Deviant SR and ABR findings had only slight or no correlation to clinical data. Intercorrelation between SR and ABR abnormality was better but not implicit and a few cases with deviant ABR showed normal SR: The frequency of abnormal and borderline SR findings was clearly higher in bilateral than in unilateral ABR abnormality. Subclassification of ABR into an upper and a lower type of pathology did not correlate with SR abnormality.

Adult↗
PubMed1979

Military audiological aspects in noise-induced hearing losses.

The sound pressure of a single shot ranges from about 165 up to 190 dB, depending on the type of weapon. In general, most shooting practice is carried out from a sheltered shooting gallery. Groupshooting and multiple reverberations from sheltered galleries maximize the acoustic strain. Clinically the acoustic trauma can be considered to be a combination of both acute and chronic noise injury, because very intense impulse noise, such as gunfire, can injure the inner ear both mechanically and by mean of disturbances in metabolism. When the ears are not protected, acoustic trauma develops in about 10% of military conscripts and 60% of regular army personnel.

Audiometry↗
PubMed1977

The effect of loud noise on the vestibular system.

The effect of a 2 sec 113--123 dB ISO pure tone stimulus on ENG was studied. The material consisted of patients with operated and unoperated otosclerosis, normal ears, patients with sensorineural defects, and cases of chronic otitis media. ENG changes were found in 45% of patients with sensorineural hearing loss, in 35% of operated otosclerotics, in 15% of unoperated otosclerotics, in 15% of patients with chronic media, but in none of the normal-hearing patients. Most of the patients showing ENG changes felt dizzy. These results seem to imply a possible risk to patients with sensorineural hearing loss working in high noise levels.

Adult↗