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Psychological responses to noise and
vibration
Datum: 2011-04-05.......ISBN:978-91-86671-73-0
Viveka Lyberg Åhlander
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Teachers have high occupational voice demands
and is a group frequently presented at voice
clinics. Little is known about the teachers’
own view of the contribution from the environment
and about the teachers’ voice use at their work-place.
The purpose of the present thesis was ; to develop
and assess a self-rating instrument for the
rating of throat-related problems in relation
to voice, to investigate the voices and the
voice use of teaching staff in their teaching
environment, to explore the prevalence of voice
problems in Swedish teachers, to explore the
teachers’ ratings of aspects of their working
environment that can be presumed to have an
impact on vocal behavior and voice function,
to clinically assess the voice function in teachers
with self-rated voice problems and to compare
to the voice function in their vocally healthy
colleagues.
It was shown that voice problems in teachers
emerge in the interplay of the individual and
the environment and that 13% of the teachers
suffer from voice problems. Teachers with voice
problems are more affected by any loading factor
in the work-environment than their voice healthy
colleagues, and they are more perceptive of
the room acoustics. The differences between
the teachers with voice problems and their voice
healthy colleagues were shown during field-measurements
of the voice during a whole typical school day,
while the findings from the clinical examinations
of larynx and voice did not differ between the
groups Teachers with voice problems differ from
their voice healthy colleagues also in their
ratings of the time for vocal recovery and by
suffering from voice problems also without a
concurring cold. No correlation was found between
subjective assessment of voice problems and
deviations of laryngeal morphology or voice
quality. When investigating or diagnosing voice
dysfunction, the individual’s self assessment
of the problems needs to be covered. Reports
of throat-symptoms are common in investigations
of teachers’ voices. The Voice Handicap Index-Throat
proved to be a stable instrument for the estimation
of self-perceived voice and throat problems.
In conclusion: Teachers with voice problems
are more affected by vocally loading factors
in the work-environment, 13% of the teachers
suffer from voice problems and the differences
in their voice use differed from their voice
healthy colleagues’ clearest, measured during
a whole school-day.
Psychological responses to noise and
vibration
Datum: 2006-11-06 .......ISBN:91-7264-215-7
Jessica
Körning Ljungberg
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Vehicle drivers are a group of workers that
are exposed to noise and whole-body vibration
(WBV) several hours a day. Some drivers may
also be exposed to high mental loads – monitoring
and manipulating physical controls while engaging
problem solving activities often with strong
short-term memory and spatial manipulation components.
Present standards and regulations that govern
health risk assessment do not take into consideration
the complexities of these multiple exposure
environments. The effect of one factor (for
example, noise or WBV) may be different than
the effect of two factors presented together.
This thesis investigates whether the combination
of noise and WBV affects the performance of
cognitive tasks more than when the exposures
are presented separately.
A series of studies were designed to expose subjects to noise and WBV stimuli designed to simulate real life working conditions. Different combinations of subjective ratings, cognitive tests, and cortisol measurements were conducted both during and immediately after exposures, which ranged from 20 to 45 minutes.
The studies have shown that a combination of noise and WBV do not degrade cognitive performance more than a single stimulus. However, WBV can degrade attention performance after exposure is turned off when drivers have been working under high mental load during exposure. The combined stimuli are also experienced as more annoying and work is more difficult in such conditions. The exposure times and task difficulty levels used in this thesis did not produce biological stress as measured by cortisol. Nevertheless, subjective ratings are sometimes seen as early indicators of other symptoms and with increased task difficulty and/or longer exposure times there may appear other measurable outcomes of the combined stimuli.
Noise in the School environment – Memory and Annoyance.
Datum: 2004 .......ISBN:91-7283-718-7
Eva Boman
Ingela Enmarker
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Objectives.The general objectives of this dissertationwere to examine the effects of acute exposure to meaningfulirrelevant speech and road traffic noise on memory performance,and to explore annoyance responses to noise exposure in theschool environment for pupils and teachers in different agegroups.
Methods. The thesis comprises seven papers, representingdifferent methodological approaches: experiments, surveystudies and interviews. In the experiments, reported in PapersI-V, 288 pupils and teachers participated in the age groups,13-14 years (n=96), 18-20 years (n=96), 35-45 years (n=48) and55-65 years (n=48). The subjects were randomly assigned to oneof three conditions: (a) meaningful irrelevant speech, (b) roadtraffic noise, and (c) silence. The equivalent sound level inthe noise conditions was set to 66 dB(A). A test batteryreflecting episodic and semantic memory were used. The surveystudies, reported in Paper VI and VII, included 207 pupils(M=13.5) and 166 teachers (M=45.9). Two separate questionnairesmainly comprising items about annoyance, noise sensitivity andstress symptoms were administered. Paper VI presents results offocus group interviews (n=16) treating the main topics:disturbing sounds, emotions, ongoing activity, and suggestionsconcerning future changes. Results. The overall findings showedthat both noise sources affected episodic and semantic memoryto the same degree for all age groups. The results indicatedthat the similarity of semantic content between noise and thetask at hand was not the only suitable explanation model, sincea non-speech noise impaired memory as much as speech.
Results also indicated that attention effects did notmediate the obtained noise effects and that the noise effectsdid not differ between age groups. Therefore, it seemedunlikely that different memory and attentional capacities stoodout as explanatory factors of the memory effects. Sinceperformances of both episodic and semantic memory tasks wereimpaired, the explanation based on level of access to long-termmemory was also ruled out. However, the episodic memory task,reading comprehension, stood out to be most impaired by noise,suggesting that complexity of the task to perform was ofimportance. For reading comprehension there was also adifferent noise pattern obtained. Participants performance wasin this task, more impaired by meaningful irrelevant speechthan by road traffic noise. This effect indicated thatmeaningful irrelevant speech might reduce the availablecognitive resources necessary for learning the text. Theannoyance models derived from the survey studies indicated thatsensitivity acted as a mediator between hearing status andannoyance, with stress symptoms as an outcome. Whetherannoyance arises or not was also determined by control andpredictability of the noise. In the interviews a differentannoyance pattern was found, in that stress symptoms appearedto be a determinant of annoyance. To be involved, respected,take own responsibility and respect others were suggestions onhow to change the environment to become more silent.
Conclusions. For both pupils and teachers acute exposureto meaningful irrelevant speech and road traffic noiseinfluenced both the achieving and providing of knowledge. Acommon annoyance pattern was also found for pupils andteachers, where individual and situational factors were ofimportance. To achieve a more silent school environment in thefuture, the pupils pointed out that the interaction betweenthemselves and their teachers was of importance.
