Listening Effort in Cochlear Implant Users

Listening with a cochlear implant remains difficult and most listeners will report high levels of listening effort.The present study is a "pilot" aiming to evaluate listening effort for cochlear implant users. The listening effort is measured with pupillometry, by monitoring the variations of pupil size in response to different stimuli. The size of the pupil is known to increase with the listening effort. The listening effort is evaluated in two different situation: speech perception in quiet and speech perception in noise. The pupillometry measures will be compared for the two listening conditions. Moreover, the study will evaluate the relationship between objective (pupil dilatation) and subjective measures (auto evaluation) of listening effort, and between speech comprehension, cognitive abilities and listening effort.

Nowadays, cochlear implants (CI) are successfully used to rehabilitate severe to profound sensorineural hearing loss. Most CI users can understand speech in quiet, but comprehension scores drop in the presence of background noise and in adverse conditions. Listening with a cochlear implant remains very demanding and most listeners report high levels of listening effort. The aim of current auditory prostheses and cochlear implants is not only restore speech understanding, but also to restore all the cognitive functions that are associated to a listening task (e.g., memory, executive functions, attention). Evaluating the listening effort is a new way to assess the efficiency of the hearing aids or cochlear implants. The listening effort indicates the amount of cognitive resources that are dedicated to a listening task; it evaluates also the cognitive resources remaining available for the other cognitive functions. The present study is a "pilot" aiming to evaluate listening effort for cochlear implant users. The listening effort is measured with pupillometry, i. e. by measuring the pupil dilatation in response to different stimuli. The size of the pupil is known to increase with the listening effort. The listening effort is evaluated in two different situation: speech perception in quiet and speech perception in noise. Speech comprehension is measured for the two listening conditions and cognitive functions are assessed by the MOCA (Montreal Cognitive Assessment). In addition, the subjects are asked to subjectively evaluate the amount of listening effort they used in each listening situation. The pupillometry measures will be compared for the two listening conditions. Moreover, the study will evaluate the relationship between objective (pupil dilatation) and subjective measures (self evaluation) of listening effort, and between speech comprehension, cognitive abilities and listening effort.

Measure of pupil dilatation while listening to speech (monosyllabic words) in quiet and in noise. Evaluation of speech comprehension in quiet Evaluation of speech comprehension in noise Measure of cognitive functions with the MOCA (Montreal Cognitive Assessment) Auto evaluation of listening effort in quiet Auto evaluation of listening effort in noise

Measure of pupil dilatation simultaneously to the evaluation of speech intelligibility. The variation of the pupil size is monitored during the presentation of speech stimuli in quiet and in the presence of a background noise.

Three lists of 17 monosyllabic words (Lafon) are presented in quiet at 65 dB SPL. Listeners have to repeat what they understood. The results correspond to the percent of phonemes correctly identified.

Three lists of 17 monosyllabic words (Lafon) are presented in a wide band noise at 65 dB SPL with a SNR (signal to noise ratio) of +10 dB. Listeners have to repeat what they understood. The results correspond to the percent of phonemes correctly identified.

The Montreal Cognitive Assessment (MoCA) is a screening instrument to detect cognitive dysfunction. It assesses different cognitive domains: attention and concentration, executive functions, memory, language, visuoconstructional skills, conceptual thinking, calculations, and orientation. The time to administer the MoCA is approximately 10 minutes. The total possible score is 30 points. The test suggests the existence of a cognitive impairment if the participant scores less than 26 points. The test is presented on a single sheet of paper.

The participant has to represent, on a continuous line, the amount of listening effort he used when listening to the monosyllabic words presented in quiet. A score from 0 (no listening effort) to 10 (effort maximum) is extracted from his response.

The participant has to represent, on a continuous line, the amount of listening effort he used when listening to the monosyllabic words presented in the background noise. A score from 0 (no listening effort) to 10 (effort maximum) is extracted from his response.

The listening effort while listening to speech stimuli is estimated by measuring the pupil size relative to a baseline. Measures of pupil dilatation are compared between quiet and noisy conditions (+ 10 SNR: signal to noise ratio).

The listening effort while listening to speech stimuli is estimated by measuring the pupil size relative to a baseline. The peak is defined as the point in time where the maximum of pupil dilatation occurs. The amplitude of the peak of dilatation is compared between quiet and noisy conditions (+ 10 SNR: signal to noise ratio).

The listening effort while listening to speech stimuli is estimated by measuring the pupil size relative to a baseline. The peak is defined as the point in time where the maximum of pupil dilatation occurs. The latency of the peak of dilatation is compared between quiet and noisy conditions (+ 10 SNR: signal to noise ratio).

percentage of phonemes correctly identify when the speech stimuli (monosyllabic words of Lafon) are presented in quiet at 65 dB SPL

percentage of phonemes correctly identify when the speech stimuli (monosyllabic words of Lafon) are presented in a wide band noise at 65 dB SPL with a +10 dB SNR (signal to noise ratio)

Score at the MOCA. The maximum score is 30. The test suggests the existence of a cognitive impairment if the score is lower than 26.

Auto evaluation of the listening effort in quiet with Visual Analog Scale. The participant has to indicate, on a continuous line, the listening effort used in the quiet condition. A score from 0 (no effort) to 10 (maximum effort) is extracted from the VAS.

Auto evaluation of the listening effort in quiet with Visual Analog Scale. The participant has to indicate, on a continuous line, the listening effort used in the noise condition. A score from 0 (no effort) to 10 (maximum effort) is extracted from the VAS.

Inclusion Criteria: informed consent Native French speaker or fluent French speaker Patient already fitted with one or two cochlear implants Oticon Medical Can correctly identify at least 10 % of the words in monosyllabic Lafon lists in quiet Normal or corrected to normal vision Exclusion Criteria: vulnerable patients (kids, pregnant women, persons under guardianship) No Social security affiliation blindness

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