Functional Brain Abnormalities Localized in 55 Chronic Tinnitus Patients: Fusion of SPECT Coincidence Imaging and MRI

Abstract

Tinnitus is often defined as the perception of sounds or noise in the absence of any external auditory stimuli. The pathophysiology of subjective idiopathic tinnitus remains unclear. The aim of this study was to investigate the functional brain activities and possible involved cerebral areas in subjective idiopathic tinnitus patients by means of single photon emission computerized tomography (SPECT) coincidence imaging, which was fused with magnetic resonance imaging (MRI). In this cross-sectional study, 56 patients (1 subject excluded) with subjective tinnitus and 8 healthy controls were enrolled. After intravenous injection of 5 mCi F18-FDG (fluorodeoxyglucose), all subjects underwent a brain SPECT coincidence scan, which was then superimposed on their MRIs. In the eight regions of interest (middle temporal, inferotemporal, medial temporal, lateral temporal, temporoparietal, frontal, frontoparietal, and parietal areas), the more pronounced values were represented in medial temporal, inferotemporal, and temporoparietal areas, which showed more important proportion of associative auditory cortices in functional attributions of tinnitus than primary auditory cortex. Brain coincidence SPECT scan, when fused on MRI is a valuable technique in the assessment of patients with tinnitus and could show the significant role of different regions of central nervous system in functional attributions of tinnitus.

Disrupted neural activity in unilateral vascular pulsatile tinnitus patients in the early stage of disease: Evidence from resting-state fMRI

“…Husain et al pointed out that the perception of chronic tinnitus may place the subject in a task state rather than a "true resting-state" (Husain and Schmidt, 2014). However, previous studies based on SPECT (single photon emission computerized tomography) and EEG (electroencephalogram) showed increased activity in the PCC areas in chronic tinnitus patients (De Ridder et al, 2011;Farhadi et al, 2010). This may be due to the function of PCC: it mediates the processes of episodic memory (Greicius et al, 2004) and sensorimotor, as well as spatial and attentional processes (Sorg et al, 2007).…”

“…Neuroimaging, especially the resting-state functional MRI (rs-fMRI) technique, has proven to be a useful tool for studying the neural activity in patients with tinnitus (Burton et al, 2012;Chen et al, 2014;Engineer et al, 2011;Farhadi et al, 2010;Han et al, 2014;Lanting et al, 2009;Maudoux et al, 2012aMaudoux et al, , 2012bSaunders, 2007;Schecklmann et al, 2013;van der Loo et al, 2009;Vanneste et al, 2011aVanneste et al, , 2011bVanneste et al, , 2011c. However, the PT patients were excluded in these studies due to the involvement of completely different mechanisms of these two subtypes of tinnitus Husain and Schmidt, 2014;Lanting et al, 2009;Li et al, 2013;Moller, 2007;Schecklmann et al, 2013;Shi et al, 2012).…”

Repetitive Transcranial Magnetic Stimulation Treatment for Chronic Tinnitus

“…Several functional imaging studies [17][18][19][20] have shown that individuals who experience tinnitus have increased activity in the auditory cortex compared with control subjects, even in the absence of external auditory stimuli. Other studies [21][22][23] demonstrated that nonauditory brain regions might also contribute to the perception or severity of tinnitus.…”

Amygdala hyperactivity and tonotopic shift after salicylate exposure

“…Considerable effort has been directed at the identification of aberrant neural activity within the classical auditory pathway that could give rise to the phantom sound of tinnitus and hyperacusis. Human brain imaging studies have identified abnormal neural activity in many different structures within the auditory pathway of patients with tinnitus and hyperacusis, but aberrant activity has also been found outside the auditory pathway (Andersson et al, 2000; Arnold et al, 1996; Farhadi et al, 2010; Giraud et al, 1999; Langguth et al, 2006; Lockwood et al, 1998; Mirz et al, 1999; Mirz et al, 2000a; Reyes et al, 2002; Shulman et al, 1995). …”