C. Llumiguano

IMPLANTED DEEP BRAIN STIMULATOR AND 1.0 TESLA MAGNETIC RESONANCE IMAGING

There is a great need for MRI examinations of patients who have previously undergone deep brain stimulator (DBS) implantation. The current guidelines pertain only to a 1.5‐Tesla horizontal‐bore scanner complying with strict safety regulations. Moreover, almost all published in vitro and in vivo studies concerning patient safety are carried out on 1.5 Tesla MR scanners. The aim of our work is to share our clinical experience of 1.0‐Tesla brain MR imaging. During the past four years, 34 patients with different types of implanted DBS systems underwent 1.0‐Tesla MR examinations to answer diagnostic or clinical questions. Apart from the scanner type applied, all other safety instructions were strictly followed. The MRI itself made no significant difference to the measured impedances or the stimulation parameters required to achieve the optimal therapeutic results. From theoretical considerations, it may be assumed that 1.0‐Tesla MRI can be performed safely on DBS‐implanted patients, provided that all other recommendations are adhered to. J. Magn. Reson. Imaging 2006.

The impact of bilateral subthalamic deep brain stimulation on long-latency event-related potentials.

The analysis of long-latency event-related potentials (ERPs) is of importance in the evaluation of certain cognitive functions and in following their subsequent changes. The aim of the present study was to investigate whether deep brain stimulation (DBS) itself can cause changes in the configuration of the ERPs. Using a standard oddball auditory paradigm, we elicited auditory cognitive ERPs in 23 Parkinsons disease patients (in both DBS-ON and DBS-OFF conditions) and in 14 healthy controls. The P200 and P300 amplitudes and latencies, the motor reaction times and the accuracy of button pressing were compared between the DBS-ON and DBS-OFF states and subsequently correlated with the applied stimulation voltage and disease duration. Comparison of the DBS-ON and DBS-OFF conditions revealed that neither the amplitude nor the latency of the examined ERP components changed significantly. However, the behavioral and attentional aspects (e.g. the accuracy of the button pressing responses to the target signal) definitely improved after the DBS was turned on. Positive correlations were demonstrated between the P300 amplitudes over the central and frontal regions and the optimal stimulation voltage and between the disease duration and P300 latencies over the Cz and Fz sites. In conclusion, our data indicate that DBS may have different impacts on various electrophysiological parameters during the oddball paradigm.

P12.7 Dichotomy of Parkinsonian rest tremor

involuntary neck rotation to left side since February 2004. The amplitude and frequency of attacks got worse gradually. Botulium toxin A (Botox) had been injected into right sternocleidomastoid (SCM) and bilateral trapezius muscles. The result was ineffective. Series of surface EMG recording identified the major firing muscle to be migrating between bilateral upper trapezius. NEIMS were given to right or left upper trapezius according to the EMG findings. Results: After seven times of treatment (once per week, 5–10 min per treatment) the involuntary movement improved satisfactorily. Both the EMG activity of bilateral SCM and upper trapezius muscles and patient’s subjective visual analogue scale decreased gradually. Conclusion: NEIMS successfully treated the cervical dystonia in this case. It is effective, economic and less time consuming. With EMG localization of triggering muscle, the NEIMS can be applied as an effective treatment of choice.