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Neuroplastic Changes Seen in Cochlear Implants With Preserved Hearing

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ClinicalTrials.gov Identifier: NCT02407587
Recruitment Status : Unknown
Verified March 2015 by Hayley Brooks, Manchester University NHS Foundation Trust.
Recruitment status was:  Recruiting
First Posted : April 3, 2015
Last Update Posted : April 3, 2015
Sponsor:
Information provided by (Responsible Party):
Hayley Brooks, Manchester University NHS Foundation Trust

Brief Summary:
Investigators hope to study patients with 1 cochlear implant and who have had hearing preservation surgery and compare the changes in the brain of these patients with normal hearing patients by doing a scan of the brain when listening to speech. The information investigators collect may help investigators to understand how the brain learns to hear with a cochlear implant and whether it uses the same areas in the brain to listen as in normal hearing patients as well as predict which patients will do well with a cochlear implant as a very specialised operation is needed to insert the cochlear implant in to the ear and is done by very few surgeons in the country. After the operation, patients need several months of teaching to help them learn how to hear through the implant. Having a cochlear implant requires a lot of cooperation and time from the patient and if investigators could understand how the brain learns to hear with a cochlear implant and predict which patients do well and why then we may be able to avoid unnecessary procedures.

Condition or disease Intervention/treatment Phase
Hearing Loss Device: cochlear implants Not Applicable

Detailed Description:

Cochlear implants are an established treatment for individuals with hearing loss where conventional hearing aids fail to provide appropriate hearing amplification and result in poor speech and language perception.

Although a large proportion of patients with cochlear implants are expected to do well with an implant, there is still uncertainty why some individuals do poorly.

Furthermore investigators have limited knowledge about how the brain interacts with a cochlear implant to process speech. Evidence suggests that the underlying central mechanisms responsible for processing speech using an implant are related to neuroplasticity. That is to say that the brain establishes new cortical networks between the vital auditory centres and the cochlear implant thus enabling processing of speech.

Investigators have recently completed a study comparing the cortical changes that occur in subjects with bilateral cochlear implants to normal hearing controls. In this study both groups of patients were subjected to binaural simultaneous auditory stimuli. Analysis suggests that subjects with bilateral cochlear implants and postlingual hearing loss seem to recruit similar areas of the temporal lobes to process speech as their normal hearing counterparts.

The implant recipients activations were larger and more diffuse but did not differ greatly from those described previously in normal hearing. This study provides a good comparison of hearing using bilateral cochlear implants to that of normal unaided hearing. This study provides a more realistic comparison of cortical activations due to hearing in cochlear implantees and normal hearing subjects. This is in contrast to other studies involving monaural stimulation of a unilateral cochlear implant to monaural stimulation of normal hearing subject with the contralateral normal hearing ear blocked off. Investigators are only aware of one additional study where subjects with bilateral cochlear implants have been compared to normal hearing controls.

In addition investigators did not observe any recruitment of the visual cortices in our bilaterally implanted subjects. This finding was also present in Strelnikov's study. However previous work has suggested subjects with cochlear implants rely on visual clues to process speech as a result of the degraded signal provided by the implant. It is possible that because the subjects in this study and Strelnikov's study were experienced implant users and benefited from binaural auditory stimulation, they were not dependant on audio-visual integration to process speech.

There has been an increasing trend towards hearing preservation surgery for patients undergoing cochlear implantation. Literature supports improved speech and pitch perception in quiet and noise for subjects who combine the use of their implant with any residual preserved natural hearing compared with using the implant alone. Once again the the underlying mechanisms for this are unknown. It would be of scientific interest to investigate the interaction between natural residual hearing and hearing via a cochlear implant. It is likely that this cohort of subjects process speech similarly to those with normal hearing.

Finally, studies have monitored the speech progression of implantees from before surgery to several years post implant switch on. It has been suggested that the predominant improvement in speech perception occurs in the first year of implant use. This would suggest that the neuronal networks responsible for speech processing are established very early on however, investigators are not aware of any studies which have attempted to track the evolution of the temporal cortices in new recipients of cochlear implants.


Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 20 participants
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: Cortical Activity in Subjects With Unilateral Cochlear Implants and Preserved Ipsilateral Residual Hearing and the Evolution of Temporal Cortex Changes in New Recipients of Cochlear Implants.
Study Start Date : May 2013
Estimated Primary Completion Date : October 2015
Estimated Study Completion Date : October 2015

Resource links provided by the National Library of Medicine


Arm Intervention/treatment
Experimental: unilateral cochlear implants

Study Group

PET scans for the mature patients with unilateral cochlear implants and preserved hearing

4 states and each state will be repeated 3 times Cochlear implant only Residual hearing only Combination of implant and residual hearing No auditory stimulation

Device: cochlear implants

PET scans for the mature patients with unilateral cochlear implants and preserved hearing

4 states and each state will be repeated 3 times Cochlear implant only Residual hearing only Combination of implant and residual hearing No auditory stimulation


No Intervention: Healthy volunteers
4 states and each state will be repeated 3 times Auditory stimulation Left ear only Auditory stimulation right ear only Binaural auditory stimulation Silence



Primary Outcome Measures :
  1. Increase our understanding of why outcomes following a cochlear implant are heterogenous. This information may be used to provide targeted rehabilitation for candidates performing poorly with their implants and minimise rejection of the implant. [ Time Frame: 1 year ]

    We anticipate that the recruitment of patients, data collection and analysis would take a maximum of 4 months

    Study Group

    PET scans for the mature patients with unilateral cochlear implants and preserved hearing

    4 states and each state will be repeated 3 times Cochlear implant only Residual hearing only Combination of implant and residual hearing No auditory stimulation

    Control Group

    4 states and each state will be repeated 3 times Auditory stimulation Left ear only Auditory stimulation right ear only Binaural auditory stimulation Silence



Secondary Outcome Measures :
  1. Combine the data from both of our studies and future studies in order to conduct meta-analysis to investigate further how language is processed in patients with cochlear implants. [ Time Frame: 1 year ]
  2. Determine if functional neuroimaging modalities have a future role in the selection process for potential cochlear implant candidates and in predicting outcome for each individual. [ Time Frame: 1 year ]


Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Mature users of unilateral cochlear implants who have natural preserved hearing in the implanted ear
  • Healthy volunteers with normal hearing
  • Right handed

Exclusion Criteria:

  • Individuals with neurological or psychiatric illness
  • Patients involved in additional drug trials
  • Pregnant or breast feeding women
  • Children
  • Left-handed subjects

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02407587


Contacts
Contact: Hayley Brooks 01612764902 hayley.brooks@cmft.nhs.uk

Locations
United Kingdom
Central Manchester University Hospitals NHS Foundation Trust Recruiting
Manchester, Manchester (Manchester borough), United Kingdom, M13 9WL
Contact: Hayley Brooks    01612764902    hayley.brooks@cmft.nhs.uk   
Principal Investigator: Rohini Aggrawal         
Sponsors and Collaborators
Hayley Brooks
Investigators
Principal Investigator: Rohini Aggrawal Manchester University NHS Foundation Trust

Responsible Party: Hayley Brooks, Rohini Aggrawal, Manchester University NHS Foundation Trust
ClinicalTrials.gov Identifier: NCT02407587     History of Changes
Other Study ID Numbers: R01997
First Posted: April 3, 2015    Key Record Dates
Last Update Posted: April 3, 2015
Last Verified: March 2015

Additional relevant MeSH terms:
Hearing Loss
Hearing Disorders
Ear Diseases
Otorhinolaryngologic Diseases
Sensation Disorders
Neurologic Manifestations
Nervous System Diseases
Signs and Symptoms