LABORATORY MEASURES OF EMOTIONAL RESPONSES
Most of the variability in emotions can be attributed to two dimensions: valence and arousal. Valence is the extent to which an emotion is considered pleasant (compared with unpleasant), while arousal is the extent to which an emotion is deemed exciting (compared with calming; Am Psychol. 1985;98:219 http://bit.ly/2lOgz2g). To measure emotional responses in the laboratory, we used sounds from the International Affective Digitized Sounds corpus, second edition (IADS-2; Tech Rep. 2007;B). IADS-2 sounds are all non-speech sounds that encompass a range of emotions across both dimensions. We used sounds expected to make people feel pleasant/excited (e.g., laughter), pleasant/less excited (e.g., music), neutral (e.g., animal noises), unpleasant/excited (e.g., crying), and unpleasant/less excited (e.g., coughing).
To measure how participants feel when listening to sounds, we used the Self-Assessment Manikin (SAM; J Behav Ther and Exp Psy. 1994;25:49 http://bit.ly/2lOk20N). For each dimension, the SAM includes five pictorial representations of emotions across a dimension. For example, the valence dimension includes a smiling face on the far left, a frowning face on the far right, and three intermediate pictures between the happy and sad faces. Under the five pictures, the numbers 1 through 9 are equally spaced, where 1 indicates “high unpleasantness,” 5 indicates “neutral,” and 9 indicates “high pleasantness.” Similarly, in measuring the arousal dimension, the SAM indicates a figure in the far left that represents high excitement and a figure on the far right that represents calm and peace, with three intermediate figures between the extremes. Numbers 1 through 9 are also displayed under thee figures, but a rating of 1 indicates “calm,” 5 indicates “neutral,” and 9 indicates “high excitement.”
During testing, a listener is seated in a sound-attenuating audiometric test booth. IADS-2 sounds are presented from a loudspeaker directly in front. All sounds have the same peak levels, and are presented at a moderate volume. Immediately after each sound, the participant used a computer keypad to rate his or her emotional response. First, the SAM valence figures are displayed. After the participant keys in a response, the SAM arousal figures are displayed. Sounds are presented at random, and the total test time is limited to avoid fatigue among the participants.
EFFECTS OF HEARING LOSS
We recently completed a study investigating the effects of hearing loss and age on emotional responses to sounds (J Speech Lang Hear R. 2016;59:1233 http://bit.ly/2lOmSDb). Participants included young adults (22-34 years old) with normal hearing; older adults (48-80 years old) with normal hearing through 4,000 Hz; and older adults (49-78 years old) with bilateral, symmetrical, mild to moderate-severe sensorineural hearing loss. All participants rated their responses to the IADS-2 non-speech sounds.
Figure 1 shows the valence ratings from study participants as a function of pure-tone average (0.5, 1.0, 2.0, and 4.0 kHz). Data in this figure reflect those from the published study and a follow-up study (in preparation). As expected, participants generally felt pleasant when listening to pleasant sounds, and unpleasant when listening to unpleasant sounds. Evident in Figure 1 is the effect of hearing loss on ratings of valence. As the degree of hearing loss increases, the range of emotional responses diminishes. Ratings of valence were reduced in response to pleasant sounds and were elevated in response to unpleasant sounds; ratings of all sounds were closer to “neutral” than the ratings of listeners with better hearing. Notably, the ratings did not change as a function of age, with younger and older listeners with normal hearing responding similarly. These data suggest that listeners with sensorineural hearing loss are less emotionally affected by sounds than their peers with normal hearing. Although the implications of this finding have not been fully, scientifically explored, they intuitively suggest that hearing loss disrupts emotional processing. As a result, people with hearing loss may not be fully benefiting from activities that their peers with normal hearing find pleasurable, like laughing with friends or listening to music.
In a follow-up study, we investigated the potential effects of hearing aid use on emotional responses to sound. Twenty-three older patients (49 to 74 years old) with hearing loss rated their responses to valence and arousal without hearing aids (unaided) and with bilateral, behind-the-ear hearing aids fit to prescriptive targets (aided). Test conditions were counterbalanced, and the sounds were presented at a moderate level. Figure 2 shows the average ratings of valence for sounds under the five expected stimulus categories in the two test conditions. These preliminary data indicate that ratings of valence were generally consistent with the expected ratings of valence; pleasant sounds were rated as pleasant and unpleasant sounds were rated as unpleasant. In addition, most patients rated pleasant and unpleasant sounds as just slightly different from neutral, consistent with a reduced range of emotional responses. Unfortunately, the figure also demonstrates there was no effect of hearing aid use on ratings of valence.
Our current research suggests that fitting hearing aids using the popular prescriptive fitting method did not improve the way patients with hearing loss felt about sounds. We continue to investigate intervention strategies that may improve the emotional responses of patients with sensorineural hearing loss, from both the technological and counseling perspectives. We hope that through further research, we can improve patient services not only in hearing aid satisfaction but also in how they feel about the sounds that fill their lives.Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.