Response to Transcranial Direct Current Stimulation in a Case of Episodic Obsessive Compulsive Disorder.

Abstract

To the Editor: R e. “500-mA ECT—A Proof of Concept Report” by Prashanth Mayur, Anthony Harris, and Bangalore Gangadhar, published as Letter to the Editor on Journal of ECT: June 2015, Volume 31, Issue 2: p e23–e26, I would like to question the methodology involved. In the text, the authors claim that 500 mA pulses are less effective than 800 mA and question that “other ECT parameters may have to be increased to maintain the total energy delivered to the patient to obtain a well-formed seizure on electroencephalogram”; they also claim that “it is not clear if the amplitude reduction resulted in a stimulus dose that was significantly suprathreshold.” My problem with this approach and conclusions is that brief pulse machines, like the MECTA spECTrum 5000Q (MECTA Corporation, Lake Oswego, Ore) they used, allow for a complete control of the electrical stimulus being used. Total electrical charge ismeasured inmillicoulombs (mC), calculated by multiplying the 4 parameters of the brief pulse and then by 2 in biphasic machines (like the one they use, as can be easily verified by the reported parameters). Not only “other ECT parameters may have to be increased” but “other ECT parameters should have been increased” to compensate for lower amperage. To reduce amperage without this compensation created 2 variables influencing the result: lower dosage and different amperage. The authors themselves state that the patients had titrated seizure thresholds (ST) of 19.2 and 72 mC and were being treated with a dosage of 115.2 and 432 mC (6 times above ST), respectively. This means that the stimulus given by the 500 mA pulses of 72 and 270 mC were as follows: a) lower dosages and b) 3.75 times above ST.