Jan H. Hulshof

The value of carbamazepine in the treatment of tinnitus

A double-blind controlled trial on the use of oral carbamazepine in the treatment of tinnitus is reported. The effects of carbamazepine and intravenous lidocaine on tinnitus were compared. Carbamazepine had less effect than the placebo.

Tinnitus suppression by intravenous lidocaine in relation to its plasma concentration

In a double‐blind controlled trial in nine patients with tinnitus we measured the lidocaine plasma concentrations during and after intravenous administration of lidocaine or placebo and scored the level of tinnitus on a visual analog scale. No patient showed any effect during the placebo infusion. Administration of lidocaine resulted in total suppression or suppression to a non‐annoying level of tinnitus in five patients, slight suppression but still annoying tinnitus in two patients, and worsening tinnitus in one patient. No effect of lidocaine was observed in one patient. Most relief was obtained at plasma concentrations between 1.5 and 2.5 µg/ml. In this concentration range a significant (p < 0.05) effect of lidocaine on tinnitus was observed. However, notable side effects were observed at plasma concentrations greater than 2.0 μg/ml. The effect persisted until plasma levels of about 0.5 μg/ml were reached. A large variability in the effects existed because of variations in lidocaine kinetics and because of the presumed psychologic components of tinnitus.

The value of tocainide in the treatment of tinnitus

SummaryWe assessed the value of tocainide in the treatment of tinnitus by performing a double-blind controlled trial in which each of 48 patients with annoying tinnitus received either tocainide HCl 900 mg/day or a placebo. Before the trial, the effect of intravenous lidocaine was evaluated in each patient so that both lidocaine and tocainide could be compared in altering tinnitus. We found that tocainide appeared to have no better effect than the placebo, whereas lidocaine suppressed tinnitus in 81% of the patients treated. The mechanisms of action of both drugs as well as their influence on tinnitus are discussed, as are the side effects of tocainide.

Vestibular investigations in acoustic neuroma

Forty-eight patients with surgically proven acoustic neuroma were examined preoperatively with a comprehensive battery of vestibular tests. In 87% of the patients, reduced caloric responses were measured on the side of the lesion. In 60% of the patients a non-responsive labyrinth was found. Spontaneous nystagmus was observed in 29% of the patients. A significant correlation with the size of the tumour was found in the occurrence of abnormal saccades in the calibration test, pathological smooth pursuit movements and the occurrence of gaze nystagmus, respectively. There was no correlation between the magnitude of the caloric response reduction and the mean hearing loss, which suggests that the hearing loss and the vestibular function loss do not occur synchronously. This study shows that in most cases of acoustic neuroma, the peripheral part of the vestibular system is severely disturbed. Abnormalities in the central and peripheral part of the vestibular system are more easily recognized with increasing tumour size. We conclude that a complete battery of vestibular tests is essential in combination with audiometric, neurologic and radiologic analysis for the early clinical diagnosis of acoustic neuroma.

The Value of Flunarizine in the Treatment of Tinnitus

The suppressive effect of flunarizine on tinnitus was assessed in a double-blind trial in 50 patients with tinnitus due to various causes. The duration of the study was 6 weeks. Serum levels of the drug were determined. The patients subjective assessment of the effect was taken as criterion for the evaluation; objective tests were found to be unsuitable for this purpose. Ten of the patients suffered from dizziness as a secondary complaint. For the group as a whole, there was no difference between flunarizine and the placebo with respect to the effect on tinnitus, but in the 10 patients with dizziness as well there was a significant difference in favor of the drug. Conclusions cannot be drawn as to the reason for this divergence, because the number of patients was too small.

The Effect of Intra-venous Lidocaine and Several Different Doses Oral Tocainide HCl on Tinnitus A Dose-finding Study

As part of preliminary studies for an investigation to assess the place of some drugs, including tocainide HCl, in the treatment of tinnitus, the present study was performed to establish the appropriate dose for tocainide. The effect of lidocaine HCl on tinnitus was studied in a double-blind controlled cross-over study in 22 patients. Lidocaine appeared to give significant relief. To select an optimal daily dose for the lidocaine analog tocainide HCl, this drug was administered orally to 19 patients with obstructive tinnitus in seven 4-day periods. This could be done in a single-blind controlled trial. A different dose was given in each period. Comparison of the effect on tinnitus and the associated side effects led to the choice of a daily dose of 900 mg. The effect of lidocaine HCl appeared to have no prognostic value for the effect of tocainide HCl on the tinnitus in the individual patient.

The Loudness of Tinnitus

Although tinnitus causes considerable suffering to many patients, its loudness is small in most cases. Traditionally the loudness is measured with a binaural loudness balance procedure. It is stated that when there is recruitment in the ear to which the test tone is presented, the intensity of the test tone is smaller than its loudness. Therefore in the case of recruitment in the ear to which the test tone is presented, the loudness of tinnitus will be underestimated. In this study the loudness in a group with recruitment in the ear to which the test tone was presented was compared with the loudness in a group with a normal ear to which the test tone was presented. The present results show that although recruitment does have a certain effect, it is very small.