The overall goal of this project is to develop a better understanding of the functional neuroanatomy of the auditory system and how this is affected by tinnitus, sensorineural hearing loss (SNHL) and phenomena associated with SNHL such as loudness recruitment. In preliminary studies, using positron emission tomography (PET) to measure cerebral blood flow (CBF), we have identified spontaneous neural activity in the central auditory system associated with tinnitus, evidence for plastic reorganization of central auditory systems, and links between sensory-motor systems and limbic and frontal brain regions that may mediate the emotional disability associated with tinnitus. We will broaden our successful preliminary approach by using statistical parametric mapping (SPM) to map CBF to focus on 5 specific aims: 1) What is the relationship between the intensity of an external tone and the degree of activation in the auditory cortex for subjects who have: (A) normal hearing, (B) loudness recruitment and (C) loudness recruitment plus tinnitus? 2) What effects do tinnitus and SNHL have on resting neural activity and what are the effects of high-frequency SNHL and tinnitus on the cortical frequency-place map? 3) What regions of the cerebral cortex are activated in patients who can modulate the loudness or pitch of their tinnitus with an oral-facial movement or eye movements? 4) Do lidocaine and residual inhibition reduce activity in regions of the brain activated by tinnitus? 5) What is the anatomical link between tinnitus and depression? This application of advanced imaging technology to study patients with communication disorders to investigate perception, and plasticity in the central auditory system should elucidate normal sensory processing of auditory information and how this is disturbed by tinnitus and SNHL. We expect to identify neural systems mediating tinnitus and related phenomena that will lead to the development of rational therapy targeted at affected neural areas.
| Reyes, Samuel A; Lockwood, Alan H; Salvi, Richard J et al. (2005) Mapping the 40-Hz auditory steady-state response using current density reconstructions. Hear Res 204:1-15 |
| Lockwood, Alan H (2005) Tinnitus. Neurol Clin 23:893-900, viii |
| Reyes, Samuel A; Salvi, Richard J; Burkard, Robert F et al. (2004) PET imaging of the 40 Hz auditory steady state response. Hear Res 194:73-80 |
| Reyes, Samuel A; Salvi, Richard J; Burkard, Robert F et al. (2002) Brain imaging of the effects of lidocaine on tinnitus. Hear Res 171:43-50 |
| Salvi, R J; Lockwood, A H; Frisina, R D et al. (2002) PET imaging of the normal human auditory system: responses to speech in quiet and in background noise. Hear Res 170:96-106 |
| Lockwood, Alan H; Salvi, Richard J; Burkard, Robert F (2002) Tinnitus. N Engl J Med 347:904-10 |
| Lockwood, A H; Wack, D S; Burkard, R F et al. (2001) The functional anatomy of gaze-evoked tinnitus and sustained lateral gaze. Neurology 56:472-80 |
| Coad, M L; Lockwood, A; Salvi, R et al. (2001) Characteristics of patients with gaze-evoked tinnitus. Otol Neurotol 22:650-4 |
| Kim, K; Burkard, R F; Lockwood, A H et al. (2000) Effects of background noise on audiometric thresholds during positron emission tomography: passive and active noise-reduction. Scand Audiol 29:211-6 |
| Lockwood, A H; Salvi, R J; Burkard, R F et al. (1999) Neuroanatomy of tinnitus. Scand Audiol Suppl 51:47-52 |
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