Tinnitus and Event-Related Activity of the Auditory Cortex

Abstract

A neuromagnetic study in tinnitus patients and normal-hearing controls was performed with a modified contingent negative variation (CNV) paradigm. While the warning stimulus S1 was a tone burst at an intensity well above threshold, the imperative stimulus S2 was presented at a near threshold intensity because, in the majority of cases, the perceived loudness of tinnitus is very close to the threshold for a pure tone of the same frequency. Subjects had to respond to S2 by pressing a button until its offset was detected. In this case, instead of the usual sudden cut-off of the CNV after the perception of S2, a slow negative deflection develops, the post-imperative negative variation (PINV). Its initial portion probably indicates the development of a second initial CNV because the subject had to attend also to the offset of S2. The neuromagnetic data were analysed both in the time domain and in the frequency domain (short-time spectral analysis of the classical EEG bands). The time domain waveform as well as the spectrotemporal patterns of the MEG bands exhibited deviations from the normal pattern in several tinnitus subgroups, depending on the characteristics of tinnitus (tonal vs. noisiform, monaural vs. binaural) and on the stimulation conditions (tinnitus side vs. non-tinnitus side).

The Application of Electro- and Magneto-Encephalography in Tinnitus Research – Methods and Interpretations

“…Consequently, the amplitude ratio of the P2m/N1m complex was smaller in tinnitus compared to controls. In a repeat study, the authors confirmed their earlier results and found that the P2m/N1m complex was smaller in tinnitus (114). A case report by Pantev et al (115) of a tinnitus patient who suffered acoustic trauma, showed the gradual recovery of the N1m/p2m complex to normal levels over 6 months, which correlated with steady recovery from tinnitus.…”

Recent technological advances in sound-based approaches to tinnitus treatment: A review of efficacy considered against putative physiological mechanisms

“…[13][14][15] Using MEG, Diesch and colleagues recently demonstrated that responses to the super-position of three amplitude-modulated tones were reduced in healthy controls (indicative of reciprocal inhibition), but increased in patients with tinnitus (indicative of abnormal reciprocal facilitation). This finding is compatible with the interpretation that tinnitus is associated with a reduced lateral or surround inhibition compared to control subjects.…”

“…This finding is compatible with the interpretation that tinnitus is associated with a reduced lateral or surround inhibition compared to control subjects. Similarly, a number of early studies reported abnormally enhanced transient N1 (N1m) responses to a 1-kHz tone in a group of tinnitus patients, [13][14][15] although these studies have not always been replicated. [16][17][18] One might expect such hyperexcitability to be greatest at frequencies corresponding to the tinnitus pitch and/or to the region of hearing loss.…”

Neurofeedback in der Therapie des Tinnitus

“…Andere Autoren berichten über Veränderungen der späten, kortikalen akustisch evozierten Potentiale bei Patienten mit Tinnitus [9,10,23]. Unter Stimulierung des Hörsystems mit bestimmten Ton-Bursts gelang mit Hilfe von Magnetenzephalographien bei einigen Tinnituspatienten der Nachweis von veränderten Potentialen im Vergleich zu Normalpersonen [11].…”