Modulation of symptomatic palatal tremor by magnetic stimulation of the motor cortex.

OBJECTIVES: Magnetic stimulation of the motor cortex can be used to determine the involvement of the cortex in rhythmic movement disorders. Symptomatic palatal tremor (SPT) is thought to come from a pacemaker that is relatively resistant to internal and external stimulation. In this study, we investigated the effect of magnetic stimulation of motor cortex on SPT. METHODS: Five male patients, aged 67-79 years, with SPT after brain stem infarction or hemorrhage, all had a synchronous mouth angle twitch with the palatal movement. Electromyographic activity was recorded with a monopolar needle electrode from orbicularis oris. In experiment 1, transcranial magnetic stimulation (TMS) was delivered at 200% motor threshold (MT) to reset SPT. In experiment 2, the effect of TMS intensities was studied at 80-240% MT in two SPT patients. To determine the influence of the TMS, we used the resetting index (RI). RESULTS: TMS reset the tremor in all 5 SPT patients at 200% MT with RIs of 0.86-0.96. The latency of the tremor reappearance after TMS was longer than the pre-stimulus tremor interval, and the intervals between the subsequent tremor bursts were also prolonged. The degree of tremor resetting was closely correlated with the magnetic stimulus intensity and the latency of the tremor reappearance after TMS. CONCLUSIONS: Stimulation of the motor cortex may modulate the generator of SPT.

Evidence for decreased salivary function in patients with reflux esophagitis.

It has been speculated that impaired salivary flow contributes to abnormal acid clearance of the esophagus in gastroesophageal reflux and results in reflux esophagitis (RE). To test this hypothesis, salivary functions were measured by quantitative salivary scintigraphies in patients with RE and in age- and sex-matched controls for comparison. Nineteen patients with RE and 36 healthy volunteers were enrolled in the study. After an intravenous injection of 5 mCi Tc-99m pertechnetate, sequential images of 1 min/frame were acquired for 30 min. The 1- and 15-min uptake ratios (UR) of the tracer in the four major salivary glands over the backgrounds were calculated. Saliva excretion was stimulated by 1 tablet of 200 mg ascorbic acid given orally 15 min after injection of the tracer, then the maximal excretion ratios (ER) of the four major salivary glands were calculated for the sialagogue stimulation. RE patients had lower values of 1st and 15th min UR and maximal ER than controls in the 4 major salivary glands. Poor salivary functions which represented a decrease in both UR and ER for patients with RE have been confirmed by quantitative salivary scintigraphy in this study.