Technology and the Future of Cochlear Implants

Late Bilateral Sequential Cochlear Implant and Quality of Life

Introduction  Hearing impairment is one of the main disorders that can interfere with the development of speech and language. In an individual, it can cause significant communication difficulties, social isolation, negative feelings, and depressive disorders. The hearing aids (HAs) and cochlear implant (CI) are options for profound and severe hearing loss, and the CI can be indicated for individuals who do not obtain benefits from HAs. Objective  To evaluate the quality of life of individuals who underwent sequential bilateral CIs with a long surgical interval between procedures. Methods  Fifteen patients, aged 8 to 70 years old, who underwent sequential bilateral CI, with an interval ≥ 4 years between surgeries, were evaluated. Quality of life was evaluated using three questionnaires: WHOQOL-BREF, SSQ-12 and HHIA in Portuguese. Results  The WHOQOL-BREF questionnaire showed that the study participants had a good quality of life in all domains assessed. According to the SSQ-12, few reported inability to listen in communication situations. Most individuals were classified as having medium disability by the HHIA, but the social and emotional effects did not significantly affect the quality of life. Conclusion  The use of questionnaires to assess the quality of life of patients with hearing impairment is a valuable tool to measure adaptation to CI. Patients undergoing bilateral sequential CI, even with a long interval between procedures, presented high indices of quality of life.

Medical devices early assessment methods: systematic literature review

OBJECTIVES

The aim of this study was to get an overview of current theory and practice in early assessments of medical devices, and to identify aims and uses of early assessment methods used in practice.

METHODS

A systematic literature review was conducted in September 2013, using computerized databases (PubMed, Science Direct, and Scopus), and references list search. Selected articles were categorized based on their type, objective, and main target audience. The methods used in the application studies were extracted and mapped throughout the early stages of development and for their particular aims.

RESULTS

Of 1,961 articles identified, eighty-three studies passed the inclusion criteria, and thirty were included by searching reference lists. There were thirty-one theoretical papers, and eighty-two application papers included. Most studies investigated potential applications/possible improvement of medical devices, developed early assessment framework or included stakeholder perspective in early development stages. Among multiple qualitative and quantitative methods identified, only few were used more than once. The methods aim to inform strategic considerations (e.g., literature review), economic evaluation (e.g., cost-effectiveness analysis), and clinical effectiveness (e.g., clinical trials). Medical devices were often in the prototype product development stage, and the results were usually aimed at informing manufacturers.

CONCLUSIONS

This study showed converging aims yet widely diverging methods for early assessment during medical device development. For early assessment to become an integral part of activities in the development of medical devices, methods need to be clarified and standardized, and the aims and value of assessment itself must be demonstrated to the main stakeholders for assuring effective and efficient medical device development.

Observation of cortical activity during speech stimulation in prelingually deafened adults with cochlear implantation by positron emission tomography-computed tomography

OBJECTIVES

We evaluated the cortical activity of 2 successful prelingually deafened adult cochlear implant (CI) users who have been trained by auditory-verbal/oral communication since childhood.

METHODS

Changes in regional cerebral blood flow were measured by positron emission tomography using '8F-fluorodeoxyglucose while the subjects were receiving auditory language stimuli by listening to a story. Ten normal-hearing volunteers were observed as age-matched control subjects.

RESULTS

In both cases, the auditory-related regions, when compared to same regions in the control subjects, showed hypermetabolism in the left dorsolateral prefrontal cortex and the left precentral gyrus--similar to that in successful CI users who are prelingually deafened children or postlingually deafened adults. Both subjects had the ability to activate these areas, and this ability might be one of the reasons that accounts for such exceptionally good performance in older prelingually deaf CI users. As for the visual-related regions, hypometabolism was observed in Brodmann areas 18 and 19, and this finding might be related to the intensive auditory-verbal/oral education that the subjects had received since childhood.

CONCLUSIONS

Despite the limits imposed by the small sample size and the spatial resolution of positron emission tomography, this study yielded insights into the nature of the brain plasticity in prelingually deafened adults who are successful CI users.

Effects of frequency allocation on lexical tone identification by Mandarin-speaking children with a cochlear implant

CONCLUSION

Frequency allocation with extended frequency ranges yielded significantly higher accuracy in pediatric CI recipients' lexical tone identification. These findings suggest that frequency allocation with extended frequency ranges may be useful in improving lexical tone recognition for at least some pediatric CI recipients.

OBJECTIVES

To assess the effects of frequency allocation on lexical tone identification by Mandarin-speaking children with a cochlear implant (CI).

SUBJECTS AND METHODS

In a prospective study, 15 prelingually deafened children between 7.17 and 16.17 years of age served as participants. Using Med-el CI devices, each participant's accuracy in lexical tone identification was compared in two conditions: first, the experimental condition, i.e. use of the extended frequency range from 233 to 8501 Hz; second, the control condition, i.e. use of the participant's clinically assigned frequency range from 300 to 8404 Hz.

RESULTS

The group mean of pediatric CI users' accuracy in lexical tone identification was 88.02% (SD = 6.31%) in the experimental condition and 83.82% (SD = 9.84%) in the control condition. The group mean was 4.20% (SD = 5.48%) higher in the experimental condition than that in the control condition; this difference was statistically significant (t(14) = 2.97, p=0.010).

Fundamental frequency discrimination and speech perception in noise in cochlear implant simulations

Increasing the number of channels at low frequencies improves discrimination of fundamental frequency (F0) in cochlear implants (Geurts, L., Wouters, J., 2004. Better place-coding of the fundamental frequency in cochlear implants. J. Acoust. Soc. Am. 115 (2), 844-852). We conducted three experiments to test whether improved F0 discrimination can be translated into increased speech intelligibility in noise in a cochlear implant simulation. The first experiment measured F0 discrimination and speech intelligibility in quiet as a function of channel density over different frequency regions. The results from this experiment showed a tradeoff in performance between F0 discrimination and speech intelligibility with a limited number of channels. The second experiment tested whether improved F0 discrimination and optimizing this tradeoff could improve speech performance with a competing talker. However, improved F0 discrimination did not improve speech intelligibility in noise. The third experiment identified the critical number of channels needed at low frequencies to improve speech intelligibility in noise. The result showed that, while 16 channels below 500Hz were needed to observe any improvement in speech intelligibility in noise, even 32 channels did not achieve normal performance. Theoretically, these results suggest that without accurate spectral coding, F0 discrimination and speech perception in noise are two independent processes. Practically, the present results illustrate the need to increase the number of independent channels in cochlear implants.

How we do it: patient participation in cochlear implant selection

. Involving patients and parents in the choice of their cochlear implant encourages an active role in the process and facilitates 'bonding' and 'ownership' of the device. . The most frequent reasons given by patients for selecting a device included cochlear implant comfort and appearance. . We describe the Implant Programme based at the Royal National Throat, Nose and Ear Hospital, London, and also examine patient satisfaction with the scheme.

Dynamics of Auditory Plasticity after Cochlear Implantation: A Longitudinal Study

Human representational cortex may fundamentally alter its organization and (re)gain the capacity for auditory processing even when it is deprived of its input for more than two decades. Stimulus-evoked brain activity was recorded in post-lingual deaf patients after implantation of a cochlear prosthesis, which partly restored their hearing. During a 2 year follow-up study this activity revealed almost normal component configuration and was localized in the auditory cortex, demonstrating adequacy of the cochlear implant stimulation. Evoked brain activity increased over several months after the cochlear implant was turned on. This is taken as a measure of the temporal dynamics of plasticity of the human auditory system after implantation of cochlear prosthesis.

Cochlear Implants and Quality of Life: A Prospective Study

OBJECTIVE

To evaluate changes in quality of life, anxiety, and depression after cochlear implantation in adults.

DESIGN

Twenty-seven postlingually deafened adults who had received a MED-EL Combi 40+ implant were investigated. One generic Health-Related Quality of Life measure, the SF-36, two disease-specific measures, the Patient Quality of Life Form (PQLF) and the Index Relative Questionnaire Form (IRQF) completed by a near relative to the patient, in addition to a domain specific measure, the Hopkins Symptom Check List 25 items (HSCL-25), were used in a prospective study. The subjects were investigated before surgery and 12 to 15 months after surgery.

RESULTS

The scores were significantly better after surgery in four of six categories of the PQLF. In the IRQF, where a family member of the cochlear implant recipient was studied, the scores were significantly better in four of five categories. There was a significant improvement in the HSCL-25 scores after surgery. In the SF-36, only one of eight scales showed significant improvement.

CONCLUSIONS

Cochlear implants were associated with statistically significant improvement in quality of life in postlingually deafened adults. The improvements were largest in the categories concerning communication, feelings of being a burden, isolation, and relations to friends and family. The implants also improved the relatives' daily lives. There was a statistically significant reduction in degree of depression and anxiety. Reduction in anxiety and depression was associated with gain in quality of life.