This study was supported by the NIH: National Center for Research Resources Centers of Biomedical Research Excellence (COBRE) Grant Number RR20146 & 1UL1RR029884; National Institute of Neurological Disorders and Stroke NS39348; National Institute of Child Health and Human Development HD055677 and HD055269; and by a Tinnitus Research Consortium Grant-in-Aid. Dr. Jeffery Myhill served as a study coordinator.
Article first published online: 1 FEB 2011
Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.
Volume 121, Issue 4, pages 815–822, April 2011
How to Cite
Mennemeier, M., Chelette, K. C., Allen, S., Bartel, T. B., Triggs, W., Kimbrell, T., Crew, J., Munn, T., Brown, G. J. and Dornhoffer, J. (2011), Variable changes in PET activity before and after rTMS treatment for tinnitus . The Laryngoscope, 121: 815–822. doi: 10.1002/lary.21425
The authors have no conflicts of interest to disclose.
- Issue published online: 23 MAR 2011
- Article first published online: 1 FEB 2011
- Accepted manuscript online: 4 JAN 2011 03:47PM EST
- Manuscript Accepted: 13 OCT 2010
- Manuscript Received: 2 SEP 2010
- Transcranial magnetic stimulation;
- PET imaging;
- Level of Evidence:1b
The objective was to determine whether low-frequency repetitive transcranial magnetic stimulation (rTMS) improves tinnitus by decreasing neural activity in auditory processing regions of the temporal cortex and the utility of positron emission tomography (PET) for targeting treatment.
Randomized, sham-controlled crossover.
Patients received a five-day course of active and sham 1-Hz rTMS (1800 pulses at 110% of motor threshold) to the temporal cortex, with a week separating active and sham treatment. Visual analogue ratings of tinnitus loudness (VARL) were assessed at baseline and the end of each treatment week; regional brain blood flow (rBBF) and glucose metabolism (via PET) were measured before and after treatment in regions of interest (ROI) beneath the stimulating coil and control sites.
The VARL for both ears significantly decreased after active but not sham treatment. Responders comprised 43% of patients, experiencing at least a 33% drop in tinnitus loudness. The site most consistently associated with a positive response was the secondary auditory cortex (Brodmann Area 22) in either hemisphere. PET asymmetries were variable across patients and not always accessible to rTMS. Whereas PET activity decreased significantly beneath the stimulating coil following active treatment, similar changes occurred at control sites and after sham stimulation. Change in tinnitus perception did not correlate significantly with change in PET activity at the treatment site ROI.
Active TMS led to a significant reduction in tinnitus loudness, but PET scans failed to support the hypothesis that low-frequency rTMS improves tinnitus by reducing cortical activation at the stimulation site, questioning the utility of PET for targeting rTMS. Laryngoscope, 2011