to measure neural activity of the central nervous system in tinnitus related brain areas in cochlear implant recipients with chronic tinnitus and to determine the relation between this neural activity and the subjective tinnitus experience of…
ID
Source
Brief title
Condition
- Inner ear and VIIIth cranial nerve disorders
- Structural brain disorders
Synonym
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
The main outcome measure will be the change in cortical activity in cochlear
implant recipients who experience subjective improvement of tinnitus by turning
the cochlear implant on compared to cochlear implant recipients who do not
experience improvement of tinnitus by turning the cochlear implant on.
Secondary outcome
Not applicable.
Background summary
Tinnitus is the perception of sounds in the absence of a physical sound source.
It can only be perceived by the patient himself. The prevalence of tinnitus is
4.4% -20% in the general population and 66-100% in the population of cochlear
implant candidates. A key hypothesis in the pathogenesis of subjective tinnitus
is that it arises as a response of the central auditory system to peripheral
hearing loss. Peripheral hearing loss results in a decrease of afferent input
to the brainstem. This may result in an increase of spontaneous neural activity
at several levels in the auditory brainstem and cortex, which is believed to
potentially cause tinnitus. Previous studies show that cochlear implants have a
positive influence on the tinnitus experience in 40-86% of cochlear implant
recipients. In this study we will investigate the influence of a cochlear
implant on the neural activity in tinnitus related brain areas and see if this
corresponds with subjective tinnitus experience of the patients. Positron
emission tomography (PET) is an imaging modality that can be used to study
neural activity in the human brain and a PET scan can in this way identify
mechanisms that underlie the generation of tinnitus in humans. Labelled water
(H215O) PET scans are, with a half life time of 2 minutes, the PET scans with
the best temporal resolution and are the best type of PET scans for detecting
changes in cortical activity. Our hypothesis is that subjective tinnitus
inhibition by a cochlear implant is reflected in a decrease of activity of the
central nervous system. This would be confirmed if switching on the implant
corresponds to a decrease of H215O PET signals from cortical brain areas.
Study objective
to measure neural activity of the central nervous system in tinnitus related
brain areas in cochlear implant recipients with chronic tinnitus and to
determine the relation between this neural activity and the subjective tinnitus
experience of patients.
Study design
observational case control study
Study burden and risks
The amount of injected radioactive matherial (12 scans of 500 MegaBecquerel
(MBq)) results in an amount of radiation of approximatel 5,6 milliSievert (mSv)
(International Commission on Radiological Protection 80). In comparison,
according to the *Rijksinstituut voor Milieuhygiëne (RIVM)*, the annual
radiation dose in the Netherlands in 1.7 mSv. According to the international
commission on radiological protection (ICRP) the estimated risk for this
scanning procedure is categorised a IIb, minor to intermediate level of risk,
1-10mSv.
No adverse of serious adverse events are to be expected during H215O
PET-scanning. The physical discomfort during the scanning procedure is minimal.
The subject will be asked to lay quiet in the scanner for 12 times 2 minutes in
a dark surrounding with a head immobiliser.
Before and after every scan the patients are asked to rate the loudness of
their tinnitus on a scale from 0-10.
Hanzeplein 1, postbus 30.001
9700 RB, Groningen
NL
Hanzeplein 1, postbus 30.001
9700 RB, Groningen
NL
Listed location countries
Age
Inclusion criteria
10 healthy one-sided cochlear implant recipients who experience inhibition of their chronic tinnitus (> 3 months, perceived in the head, constant in presence)by turning the cochlear implant on, age > 18, right handed.
10 healthy one-sided cochlear recipients who do not experience inhibition of their chronic tinnitus (> 3 months, perceived in the head, constant in presence) by the cochlear implant, age >18, right handed.
Exclusion criteria
Presence of any major medical, neurological or psychiatric diagnoses now or in the past, specific epilepsy, severe head injury or previous cranial neurosurgery, participation in a study with radiation exposure in the year prior to this study, radiological workers, use of drugs or medications that reduce cortical excitation such as anticonvulsants, benzodiazepines or other sedatives (e.g. antihistamines), pregnancy.
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL33216.042.10 |