Behavioral Manifestations of Listening Effort
| Status: | Enrolling by invitation |
|---|---|
| Healthy: | No |
| Age Range: | 18 - 40 |
| Updated: | 9/16/2018 |
| Start Date: | July 15, 2017 |
| End Date: | July 15, 2019 |
The purpose of this investigation is to investigate the behavioral manifestations of
listening effort. Quantifying listening effort based on an easy to measure behavioral metric
would allow for better understanding of the effort that goes into processing conversational
speech. The investigators hypothesize that the behavior modifications required to improve the
signal to noise ratio in increasingly complex listening environments significantly deviates
from quiet listening environments. Further, the investigators hypothesize that this directly
contributes to increased listening effort and reduced ability to accurately monitor content
for everyday conversation.
listening effort. Quantifying listening effort based on an easy to measure behavioral metric
would allow for better understanding of the effort that goes into processing conversational
speech. The investigators hypothesize that the behavior modifications required to improve the
signal to noise ratio in increasingly complex listening environments significantly deviates
from quiet listening environments. Further, the investigators hypothesize that this directly
contributes to increased listening effort and reduced ability to accurately monitor content
for everyday conversation.
Listening Effort has been described as a reflection of the cognitive resources necessary for
speech understanding. Measures can broadly be classified into Subjective, Physiological and
Behavioral measures of Listening Effort (LE). Subjective measures of LE involve the listener
rating or answering a questionnaire on the presented auditory stimuli. Some examples of
Subjective measures are the multidimensional speech, spatial and qualities (SSQ) scale and
Listening effort rating scale. However, these measures suffer from individual bias, for
example, what one person might find takes more effort, another might not.
Physiological measures establish relationships between changes in the central and/or
autonomic nervous system activity and LE. Effect of LE on central nervous system activity
include methods such as using Functional Magnetic Resonance Imaging (fMRI) to compare
processing of noise vocoded versus clear sentence stimuli and using Electroencephalography
(EEG) to monitor memory/cognitive load. Some methods of measuring effects on Autonomic
Nervous system are through Pupillometry and Skin Conductance. Research has found that
fluctuating pupil size may be an indicator of mental task load and/or attention, stress and
memory. Furthermore, Pupillometric methods have been used to correlate changing measures like
pupil size and listening tasks. There are some drawbacks of using pupillometry to measure LE-
Absolute pupil size and change in pupil size for presented speech change according to the age
of the listener. For instance, Older adults have been found to have smaller absolute pupil
size and show lesser change in pupil size when moving from difficult to easier listening
conditions. These drawbacks can be accounted for by normalizing the pupil size.
Behavioral measures take into account that the there is a decline in cognitive functions over
prolonged mental effort used an auditory dual task paradigm where the primary task was word
recognition and the secondary tasks were memory recall and Visual Response times. Apart from
the Dual tasks, participants were also asked to assign a subjective rating based on SSQ.
Findings revealed 1) that there is empirical evidence linking repeated instances of effortful
listening and subsequent cognitive failure and 2) self- report measures did not show the same
changes as the behavioral measures. It has been suggested that this may indicate that
subjective (self-report) measures and behavioral measures assess separate aspects of fatigue.
It may also be due to subjective measures having individual biases.
As mentioned above, there are numerous studies of subjective, objective and behavioral
measures of LE, yet, there are no studies of the actual behavior employed by listeners to
reduce listening effort. Further, researchers do not understand how these behaviors influence
the ability of the listener to monitor and maintain conversational speech. Listeners must
rely on both peripheral and central auditory mechanisms to process speech. As the auditory
signal increases in complexity, likewise there is an increase in the auditory processing
required to understand speech. The effort that the auditory system must put forth to process
complex signals is even greater if the signal degraded or imbedded in competing signals such
as background noise. This requires increased exertion and mental effort on the part of the
listener, and results in a reduction in ability to maintain focus and an increase in fatigue.
These issues are further amplified in the presence of a peripheral hearing disorder as
listeners do not have the mechanisms required to properly process even simple and
unchallenged auditory signals. Research has demonstrated decreasing word recognition accuracy
with decreasing Signal to Noise Ratio (SNR) and demonstrated an increase in listening effort
when speech was presented in increasingly negative SNRs. Numerous studies have reported on
the increase in listening effort required for individuals with hearing loss.
The purpose of this investigation is quantify listening effort based subjective, objective
and behavioral measures at different Signal to Noise Ratios (SNR).
speech understanding. Measures can broadly be classified into Subjective, Physiological and
Behavioral measures of Listening Effort (LE). Subjective measures of LE involve the listener
rating or answering a questionnaire on the presented auditory stimuli. Some examples of
Subjective measures are the multidimensional speech, spatial and qualities (SSQ) scale and
Listening effort rating scale. However, these measures suffer from individual bias, for
example, what one person might find takes more effort, another might not.
Physiological measures establish relationships between changes in the central and/or
autonomic nervous system activity and LE. Effect of LE on central nervous system activity
include methods such as using Functional Magnetic Resonance Imaging (fMRI) to compare
processing of noise vocoded versus clear sentence stimuli and using Electroencephalography
(EEG) to monitor memory/cognitive load. Some methods of measuring effects on Autonomic
Nervous system are through Pupillometry and Skin Conductance. Research has found that
fluctuating pupil size may be an indicator of mental task load and/or attention, stress and
memory. Furthermore, Pupillometric methods have been used to correlate changing measures like
pupil size and listening tasks. There are some drawbacks of using pupillometry to measure LE-
Absolute pupil size and change in pupil size for presented speech change according to the age
of the listener. For instance, Older adults have been found to have smaller absolute pupil
size and show lesser change in pupil size when moving from difficult to easier listening
conditions. These drawbacks can be accounted for by normalizing the pupil size.
Behavioral measures take into account that the there is a decline in cognitive functions over
prolonged mental effort used an auditory dual task paradigm where the primary task was word
recognition and the secondary tasks were memory recall and Visual Response times. Apart from
the Dual tasks, participants were also asked to assign a subjective rating based on SSQ.
Findings revealed 1) that there is empirical evidence linking repeated instances of effortful
listening and subsequent cognitive failure and 2) self- report measures did not show the same
changes as the behavioral measures. It has been suggested that this may indicate that
subjective (self-report) measures and behavioral measures assess separate aspects of fatigue.
It may also be due to subjective measures having individual biases.
As mentioned above, there are numerous studies of subjective, objective and behavioral
measures of LE, yet, there are no studies of the actual behavior employed by listeners to
reduce listening effort. Further, researchers do not understand how these behaviors influence
the ability of the listener to monitor and maintain conversational speech. Listeners must
rely on both peripheral and central auditory mechanisms to process speech. As the auditory
signal increases in complexity, likewise there is an increase in the auditory processing
required to understand speech. The effort that the auditory system must put forth to process
complex signals is even greater if the signal degraded or imbedded in competing signals such
as background noise. This requires increased exertion and mental effort on the part of the
listener, and results in a reduction in ability to maintain focus and an increase in fatigue.
These issues are further amplified in the presence of a peripheral hearing disorder as
listeners do not have the mechanisms required to properly process even simple and
unchallenged auditory signals. Research has demonstrated decreasing word recognition accuracy
with decreasing Signal to Noise Ratio (SNR) and demonstrated an increase in listening effort
when speech was presented in increasingly negative SNRs. Numerous studies have reported on
the increase in listening effort required for individuals with hearing loss.
The purpose of this investigation is quantify listening effort based subjective, objective
and behavioral measures at different Signal to Noise Ratios (SNR).
Inclusion Criteria:
- Normal Hearing
Exclusion Criteria:
- Do not meet inclusion criteria
- Pregnant women
- Prisoners
- Does not speak English
- Those displaying cognitive impairment (Potential study subjects will be screened for
potential cognitive impairments that may negatively influence control data. We will
use the validated mini mental exam)
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