Deep Brain Stimulation (DBS) for Movement Disorders: An Experience in Hospital Universiti Sains Malaysia (HUSM) Involving 12 Patients

Sinusoidal stimulation on afferent fibers can selectively activate different types of neurons in rat hippocampus

Deep brain stimulation (DBS) is a promising therapy for treating various brain disorders. Although narrow electrical pulses have been commonly used by DBS, sinusoidal waveforms have also been investigated to improve the effects of DBS therapy and to save electrical energy. However, the effect of sinusoidal stimulation on neurons is unclear yet. To investigate the modulation of sinusoidal stimulation on different types of neurons in networks, sinusoidal stimulations (50 Hz) with lower-intensity and higher-intensity were applied to the afferent axons (Schaffer collaterals) in rat hippocampal CA1 region. The firing of inhibitory interneurons and excitatory pyramidal cells (the principal neurons of CA1) during the stimulations were detected and were compared with their baseline firing before stimulations. Results showed that sinusoidal stimulation with a lower-intensity (~30 μA) can selectively activate the interneurons thereby suppressing the firing of pyramidal cells in the downstream post-synaptic region. However, sinusoidal stimulation with a higher-intensity (~60 μA) can increase the firing of both types of neurons significantly. Presumably, the two different effects of inhibition and excitation on the principal neurons by different stimulation intensities could be caused by the fact that the firing threshold of interneurons is lower than that of pyramidal cells. The results provide important clues for selective modulation of neuronal activity by brain stimulations thereby developing different stimulation paradigms to treat various brain disorders.

Epilepsy Surgery in Hospital Universiti Sains Malaysia: Our Experiences since 2004

Epilepsy surgery has been performed by a few centres in Malaysia, including Hospital Universiti Sains Malaysia (HUSM). To date, a total of 15 patients have undergone epilepsy surgery in HUSM. The epilepsy surgery included anterior temporal lobectomy (ATL) with amygdalohippocampectomy (AH) and Vagal nerve stimulation (VNS). The surgical outcomes of the patients were assessed using the International League Against Epilepsy (ILAE) outcome scale. The ILAE scores for patients who underwent ATL with AH were comparatively better than those who underwent VNS. One of the patient who underwent ATL with AH and frontal lesionectomy was found to have psychosis during follow up. Epilepsy surgery has proven to be an important treatment for medically resistant epilepsy. Thus it is important to raise public awareness regarding epilepsy and its treatment.