Continuous Video-EEG monitoring (CCTV) was initiated on a 63-year-old male admitted to the neurological intensive care unit (NICU) with sub-arachnoid hemorrhage due to rupture of a right posterior communicating artery aneurysm. During review of the overnight record a sudden change in the baseline record occurred with appearance of a rhythmic theta frequency sharply contoured waveform best visualized in the left para-sagittal and central ( Cz and Pz) leads ( Fig 1 and 2). This electrographic discharge was correctly recognized to be a non-physiological (non-cerebral) artifact generated by the to and fro rocking motion of the motorized bed on visual inspection of the concurrent video record. This motorized bed artifact further disappeared when the bed was switched off thus confirming its non-cerebral origin. With continuous EEG monitoring becoming increasingly common in the intensive care unit, correct identification of artifacts generated by the patient's surroundings is of paramount importance to prevent misinterpretation of the EEG and inadvertent over treatment.

Figure 1

Figures 1 and 2. EEG record showing a sudden change in the baseline record with appearance of a rhythmic theta frequency sharply contoured waveform best visualized in the left para-sagittal and central ( Cz and Pz) leads.

Figure 2

Correspondence to

Nitin Sethi, MD Comprehensive Epilepsy Center NYP-Weill Cornell Medical Center New York, NY 10021 Email: sethinitinmd@hotmail.com