Modifications in the brain following hearing loss in one ear version 1

• Research type

  Research Study

• Full title

  Neuroplasticity in the auditory brain following unilateral sensory deprivation

• IRAS ID

  136439

• Contact name

  Michael Maslin

• Contact email

  michael.maslin@manchester.ac.uk

• Sponsor organisation

  The University of Manchester

• Research summary

  The central auditory system has ascending neurones (nerve fibres) that project from the ear to the ipsilateral (same) and contralateral (opposite) sides of the brain. The contralateral pathways contain a greater number of neurones and this results in asymmetric (unbalanced) activation. Hearing tests have consistently shown larger activity over the hemisphere contralateral to the stimulated ear.

  There is also a growing body of evidence demonstrating that this asymmetric activation can be modified by changing the sensory input to the listener. For example, it has been shown that adults with deafness in one ear show more symmetrical activation compared with adults with two normally functioning ears. This means that whereas in people with normal hearing one side of the brain is activated more than the other, people with no hearing in one ear show equal activation on both sides of the brain.

  To date, the evidence derives from measurements of the cortex of the brain (i.e. the parts responsible for higher functioning). No evidence exists for any modifications in the subcortical regions (i.e. the brainstem) after unilateral deafness. Furthermore, there is limited information on how these modifications affect normal day-to-day hearing function for the listener with unilateral deafness.

  Th present research aims to address these gaps in knowledge. It is an area of importance since, apart from increasing fundamental scientific knowledge, there
  is some suggestion that these modifications are a compensatory mechanism for the loss of hearing in one ear. Recognising any compensatory mechanisms and the precise pattern and anatomical location may facilitate utilising them in diagnosis and rehabilitation of hearing function. For example, it may be possible to increase
  the speed of these changes

• REC name

  North West - Preston Research Ethics Committee

• REC reference

  13/NW/0807

• Date of REC Opinion

  27 Nov 2013

• REC opinion

  Favourable Opinion