1239 Deep Brain Stimulator Artifact on Polysomnography

Abstract

This is the first reported case documenting the a unique Deep Brain Stimulator (DBS) artifact during polysomnography (PSG) in a patient with primary dystonia as 100 Hz interference external artifact. A 49-y/o male with DYT1 early-onset primary dystonia (DYT1) status post bilateral globus pallidus pars interna (GPi) DBS placement presented to the sleep clinic for evaluation of sleep apnea, teeth grinding and daytime sleepiness for the past 3 years. The patient underwent a diagnostic PSG with a bruxism electromyographic montage. During the recording, a 130 Hz interference artifact was capturedseen throughout the PSG channels referred to the patient’s DBS. The DBS artifact was characterized by a series of narrow band and periodic artifact at the harmonic frequency of his DBS stimulation at 100Hz. While his DBS could be temporarily turned off at night to allow for accurate scoring, the patient declined this request. His PSG revealed severe obstructive sleep apnea. A DBS consists of electrodes implanted into the GPi that connect to an impulse generator placed subcutaneously over the chest and acts by inhibiting the abnormal brain activity responsible for dystonia. The patient’s DBS was set to a frequency of 1300 Hz, a pulse width of 450 μs and amplitude of 1.3 V to 2.3 V130 Hz. This case report illustrates the DBS interference artifact characterized by a 100Hz frequency of 130 Hz which obscuredartifact obscuring the entire PSG epoch assuming a checkerboard morphology. The DBS may be turned off during the PSG to allow for adequate sleep scoring, butthough patients may not tolerate it. The case highlights that in patients in whom DBS requires activity at night, alternative diagnostic tools excluding electroencephalography (such as home sleep apnea testing) may be considered. (HSAT) as a diagnostic tool in patients who refuse to have their DBS device deactivated at night Sleep physicians may have to consider Home Sleep Apnea Testing (HSAT) as a diagnostic tool in patients who refuse to have their DBS device deactivated at night. Alternatively, new filtering methods such matched filtering or frequency-domain Hampel filtering algorithms may be used to remove the DBS artifact from a PSG.1,2