Discussion
Baseline scores placed the majority of the sample in the severe
disability category of HUI3 multi-attribute score (Figure 1, left)
levels i.e. where at least one attribute is at a reduced level of
function that cannot be corrected and prevents many activities (Feng et
al., 2009). This is typical for a cohort of hearing-impaired individuals
with sensorineural hearing loss (Summerfield et al., 2019; Swan et al.,
2012; Barton et al 2012). After implantation, there was a significant
gain in HUI3 scores at one year which was maintained at 2 and 3 years.
At least 50% of the subjects had moved into the moderate disability
category (Figure 1, left), where at least one attribute is at a reduced
level of function that cannot be corrected and/or prevents some
activities. However, we see that most subjects reached level 3 on the
hearing attribute scale. This level describes functional hearing with
the use of a “hearing aid” (in this case a CI).
Of the factors considered in the logistic regression analysis telephone
use and the speech and emotion attributes on HUI3 were significant.
Those who did not use the telephone at baseline were 1.5 times more
likely to get a clinically meaningful gain on the HUI3 from
implantation. As expected, subjects in the poor hearing category at
baseline, (hearing attribute levels 4, 5 or 6) were also more likely not
to use the telephone (OR 1.52). Thus, telephone use is an easy parameter
to use for the screening of potential adult CI candidates presenting to
the audiology clinic. With poor access to adult hearing screening in
many countries, the capability to use the telephone use would provide a
simple criterion for urgent referral for cochlear implant assessment.
Those who reported that strangers were unable to understand them, or
even poorer verbal communication, also had a higher chance of clinically
significant gain in health utility. Improved overall verbal
communication due to better hearing and other rehabilitation following
CI may have contributed to this effect. Those who were unhappy prior to
implant were also more likely to show a meaningful gain in the HUI3,
probably due to the implant and rehabilitation process improving their
communication and thus emotional state.
The Fisher’s exact test showed that there was also a non-random
association between a meaningful gain on the HUI3 and the hearing single
attribute. Not surprisingly, those subjects with poor baseline hearing
were more likely to gain more than 0.1 points. The SSQ was still
sensitive to changes in hearing brought about by CI, even in the group
with no clinically important gain in HUI3. For that group the mean
improvement of 2.43 on the SSQ scale was highly clinically significant.