Relation between body composition, abdominal obesity, and lung function.

Reference values of spirometry and diffusion capacity are usually adjusted for age, sex, height and ethnic origin. However, also other factors, mainly weight and body composition, have an effect on pulmonary function. Therefore, we examined how body composition and abdominal obesity are related to lung function in normal population and whether they should be taken into account in the reference values. Two hundred and eighty-four healthy Finnish non-smoking adults were included in the study. Height, waist circumference, abdominal sagittal diameter and body composition were measured, and spirometry and diffusion capacity (DLCO) were performed. Muscle mass (r = 0.29, P = 0.000) and lean body mass (r = 0.29, P = 0.000) correlated positively with DLCO. However, no significant correlation between body composition and spirometry results was observed. Abdominal sagittal diameter (r = -0.21, P = 0.000) and waist circumference (r = -0.22, P = 0.000) correlated inversely with the forced expiratory volume in 1 s/forced vital capacity ratio (FEV1/FVC). In our study population, subjects with higher muscle and lean body mass had higher DLCO. This indicates a need for future re-evaluation of reference values. Besides, already minor abdominal obesity is associated with obstructive changes in spirometry results.

Occupational pharyngitis associated with allergic patch test reactions from acrylics.

A female dentist specialized in orthodontics repeatedly developed symptoms of pharyngitis at work. A chamber provocation test indicated that her symptoms were caused by acrylics. Prick tests with acrylics were negative, while patch tests were strongly positive although the patient had no skin symptoms. The relationship between the symptoms and the patch test results is discussed. It is suggested that type IV allergic reactions may be involved in symptoms of the upper respiratory tract.

Acoustic conditions for speech communication in classrooms.

The purpose of this study was to measure reverberation times, background noise levels and Rapid Speech Transmission Index (RASTI) values in occupied and in unoccupied classrooms. Probability distributions of sound levels were also measured during classroom instruction. The reverberation time was measured according to the ISO 3382-1975 standard and RASTI according to IEC 268-16. In one-third of the classrooms the reverberation times were found to be longer than 0.9 s. at one or more frequencies ranging from 250 to 2,000 Hz. In most of the unoccupied classrooms, the background noise level was 35 dB(A) or less. During classroom instruction the background noise levels (L90) were high, ranging from 40 to 58 dB(A). The equivalent continuous sound levels (LAeq) were also high, from 58 to 79 dB(A), indicating that teachers increase their vocal effort while speaking. Most classrooms had RASTI values that reflected fair intelligibility, but very few classrooms had RASTI values indicating excellent intelligibility. The acoustic design of classrooms should be based on achieving the highest possible degree of speech intelligibility for all the pupils.

Effect of sound-absorbing treatment on speech discrimination in rooms.

Noise and reverberation in a room affect speech discrimination. Sound-absorbing materials are used to shorten reverberation times. To find out the effect of acoustic treatment on speech discrimination, an acoustic refitting was carried out in a classroom and in a multipurpose hall. The normal-hearing test subjects perceived the word material (sentences, words and nonsense words) binaurally from the loudspeaker. The tests were repeated after the acoustic refitting of the rooms. The sound-absorbing treatment improved speech discrimination. In quiet, the improvement in discrimination was minimal or absent, but was well documented in a noisy environment. In rooms where speech communication takes place, attention should be paid to acoustic conditions: acoustic treatment can improve the quality of communication.

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.

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.

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.