The Fifth Eriksholm Workshop on “Hearing Impairment and Cognitive Energy” added new light to our age-old struggle to help people understand speech, especially in background noise. The collection of publications borne out of the workshop indicated that many factors not related to hearing sensitivity contribute to a person's ability to understand speech, such as the listener's working memory, cognitive energy and resources, pleasure received from understanding speech, importance of the message, signal quality and complexity of the task, listener's age, availability of visual cues, and social-psychological factors (e.g., stress, self-efficacy, negative stereotypes) among others (see Ear Hear. 2016;37 Suppl 1). With the new understanding of the interactions between listening and cognition, it is likely that audiologists in the future will be actively involved in motivating patients to engage in effortful listening, strategically allocating cognitive capacity for listening, and preventing listening withdrawals, especially in aversive listening environments (Ear Hear. 2016;37 Suppl 1:5S).
Besides the management of motivation and cognitive resources, training can be another area worthy of exploration. Two studies, in particular, examine the effects of prior and current training on people's ability to carry out musical and cognitive tasks (Front Aging Neurosci. 2017;9:149; Sci Rep. 2017;7:5808).
MUSICAL TRAINING & PERCEPTION
Moreno-Gómez and colleagues examined the effects of age, sex, formal education level, and prior musical training on music perception (Front Aging Neurosci. 2017). They recruited three groups of Chilean research participants:
Group I: 84 young controls (aged between 18 and 60 years) without hearing loss,
Group II: 49 older controls (aged > 60 years) without hearing loss, and
Group III: 42 older adults (aged > 59 years) with four-frequency pure tone averages > 35 dB HL.
The rationale was that music perception involves a complex sensorimotor and cognitive network, such as emotion, memory, reward, and motor circuits. Age-related changes in these neural circuits may therefore affect hearing, cognitive functions, and music perception.
Participants’ perception of pitch, temporal, and timber were examined using a computerized version of the Montreal Battery for the Evaluation of Amusia (MBEA), which presents pairs of melodies. The participants had to indicate whether they are the same or different. Six different musical skills were assessed:
1. Scale – participants were asked to tell whether a pair of melodies have out-of-scale elements
2. Contour – participants were asked to identify pairs with a pitch direction change
3. Interval – participants were asked to identify melodies with a changed pitch but no change in the scale or contour of the melody
4. Rhythm – participants were asked to tell whether two musical phrases have the same or different rhythm
5. Meter – participants were asked to judge whether the melody is a march (duple meter) or waltz (triple meter)
6. Musical memory – participants were asked to tell whether a melody has been heard during the previous tests
The participants’ scores were reported for each subtest, and their overall correct scores were calculated as the global MBEA scores.
The study results showed no difference between the sexes. The three groups of participants, however, differ significantly in their global MBEA and pitch scale scores, with young controls scoring the highest and older adults the lowest. In the other subtests, young controls got significantly higher scores than older adults in the contour, interval, rhythm, and music memory measures, but the differences between the two older groups were not significant. These results suggest that amusia, the inability to recognize and reproduce musical tones, occurs more often among older adults, particularly among those with hearing loss.
Additionally, participants with more formal education tend to have higher global MBEA scores. Although this trend was somehow affected by the fact that younger controls usually have longer formal education, the positive correlation between the global MBEA scores and years of formal education was apparent on the scatterplot even without the data on the young controls.
Furthermore, although young controls with and without prior musical training obtained similar global MBEA scores, older adults with musical training obtained significantly higher global MBEA scores than those without any training, regardless of their hearing status. The score difference, however, was greater between older adults with and without hearing loss. These results showed that previous musical training mediated the decline in musical abilities in old age but having hearing loss increased such decline.
MULTIMODAL TRAINING & COGNITION
In this study, Ward and colleagues examined the effectiveness of unimodal and multimodal cognitive training on improving research participants’ executive function, fluid intelligence, working and episodic memory (Sci Rep. 2017). The authors randomly assigned 518 young adult research participants to five interventions:
• Games Only Group: Fifty-nine participants played 70 minutes of cognitive training games based on executive function and working memory tasks three times for 16 weeks (i.e., 48 sessions). Five of the six training games were previously reported to induce positive changes in executive functions, working memory, and transfer effects, and a new game was added;
• Exercise and Game Group: Sixty-eight participants played adaptive training games for 20 sessions, and were engaged in 28 sessions of physical exercise that consisted of warming up, high-intensity cardiovascular exercise, resistance training, dynamic stretching, and cooling down. They also received sham transcranial direct current stimulation during the game sessions;
• Game, Exercise, and Stimulation Group: Sixty-one participants received the same treatments as the Exercise and Game Group, but they received non-invasive transcranial direct current stimulation that increased cortical excitability for 20 sessions;
• Active Control Group: Sixty-six participants played adaptive visual search and change detection games for 70 minutes in 48 sessions. The visual search and change detection games did not lead to changes in cognitive functions in previous research studies;
• No Contact Control Group: Sixty-four participants completed pre- and post-tests, but they have no contact with the research team in-between.
A total of 318 participants completed all the requirements of the study, and their performance was evaluated using:
• Adaptive training games that logged their scores at the end of each session;
• Pre- and post-test battery that evaluated their executive function, fluid intelligence, working and episodic memory, and maximum oxygen consumption;
• Post-study battery that evaluated the transfer of intervention to general intelligence based on tests examining latent constructs of executive functions, fluid intelligence, working and episodic memory; and
• A self-assessment on the expected change in their abilities such as overall intelligence, divided attention, long-term memory, and emotional regulation, by participating in the study.
Results indicated that participants in the two exercise groups had similar maximal oxygen consumption, which was significantly higher than other non-exercise groups. After completing 20 training sessions, all training groups showed significant score improvements in the six games. In addition, group effect was found for five of the six games. The multimodal groups were found to achieve higher scores than the Games Only group in games based on visuospatial reasoning, mental planning, and working memory updating. The Game, Exercise, and Stimulation Group also obtained higher scores than the other two training groups on games based on dual n-back and task switching.
Although other studies showed generalization effects of cognitive training, the post-study tests on general intelligence administered in this study did not show such an effect (Science. 2008;320:1510; Psychon Bull Rev. 2015;22:366). There was no significant difference in the attrition rate among the groups, and accounting for participants’ expectation scores did not change the results.
Taken together, the findings of both studies support the notion that prior (music) training and current (cognitive) training strengthen the neurological pathways and help people retain or improve their ability to perform the trained tasks. Future studies are needed to explore effective training paradigms to facilitate generalization of learned tasks and enhance general cognitive abilities.