Frequency-Dependent Neural Activity in Patients with Unilateral Vascular Pulsatile Tinnitus.

Han Lv,Zhenchang Wang,Ting Li,Guopeng Wang,Pengfei Zhao,Shusheng Gong,Peng Wang,Fei Yan,Rui Li,Rong Zeng,Cheng Dong,Ling Zhang,Zhaohui Liu

doi:10.1155/2016/4918186

Abstract

Previous resting-state functional magnetic resonance imaging (rs-fMRI) studies have shown that neurological changes are important findings in vascular pulsatile tinnitus (PT) patients. Here, we utilized rs-fMRI to measure the amplitude of low-frequency fluctuations (ALFF) in forty patients with unilateral PT and forty age-, gender-, and education-matched normal control subjects. Two different frequency bands (slow-4, 0.027–0.073 Hz, and slow-5, 0.010–0.027 Hz, which are more sensitive to subcortical and cortical neurological signal changes, resp.) were analyzed to examine the intrinsic brain activity in detail. Compared to controls, PT patients had increased ALFF values mainly in the PCu, bilateral IPL (inferior parietal lobule), left IFG (inferior frontal gyrus), and right IFG/anterior insula and decreased ALFF values in the multiple occipital areas including bilateral middle-inferior occipital lobe. For the differences of the two frequency bands, widespread ALFF differences were observed. The ALFF abnormalities in aMPFC/ACC, PCu, right IPL, and some regions of occipital and parietal cortices were greater in the slow-5 band compared to the slow-4 band. Additionally, the THI score of PT patients was positively correlated with changes in slow-5 and slow-4 band in PCu. Pulsatile tinnitus is a disease affecting the neurological activities of multiple brain regions. Slow-5 band is more sensitive in detecting the alternations. Our results also indicated the importance of pathophysiological investigations in patients with pulsatile tinnitus in the future.

Highlights

Tinnitus is defined as the perception of sound without external stimuli
We found that PCu with amplitude of low-frequency fluctuations (ALFF) changes in slow-4 (r = 0.342, P = 0.031) and slow-5 (r = 0.368, P = 0.019) bands had significant correlations with the clinical data of pulsatile tinnitus (PT) patients as measured using Tinnitus Handicap Inventory (THI) scores (Figures 4(a) and 4(b), resp.)
Our study suggests that the ALFF abnormalities of intrinsic brain activity in PT patients are associated with specific frequency bands and may have clinical relevance

Summary

Introduction

Tinnitus is defined as the perception of sound without external stimuli. It affects millions of people in the world. Tinnitus can be divided into pulsatile tinnitus (PT) and nonpulsatile tinnitus (NPT). PT coincides with the patient’s heartbeat, and the characterized cardiac-synchronous sound described by PT patients can be suppressed by compressing the internal carotid artery or internal jugular vein on the symptomatic side [7, 8], whereas NPT is continuous ringing sound. 4% of them are experiencing a pulsatile form of tinnitus [9]. It is estimated that there are almost twenty million PT patients all over the world

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Discussion

Conclusion