How Britain switched to brief pulse ECT

When electroconvulsive therapy (ECT) was invented in the 1930s the machines used sine wave (ordinary household) current, and the two electrodes were put one on either side of the patient’s head. And that is the way most people who have had ECT have been treated, and the way that many people are still being treated, especially in Asia but also in a smaller number of hospitals in Western countries.

But since the very early days of ECT there have been attempts to attenuate the damage done by ECT by changing the waveform of the electric shock and by changing the positioning of the electrodes. In the 1940s experiments were done with brief pulse and ultra-brief pulse currents, followed by experiments in the 1950s with unilateral ECT, where both electrodes are put on one side of the head (as opposed to bilateral, where they are put one on either side of the head). So you ended up, over 50 years ago, with four ways of giving ECT: bilateral sine wave (BL sw); bilateral brief pulse (BL bp); unilateral sine wave (UL sw) and unilateral brief pulse (UL bp). Bilateral sine wave does the most damage and unilateral brief pulse does the least, with the other two forms somewhere in the middle.

In the 1960s some British psychiatrists did an experiment in which they divided some ECT patients into four groups, BL sw, BL bp, UL sw and UL bp, and took various measurements to see how long it took them to start breathing, recover consciousness, know which day of the week it was, etc. The results were predictable: the BL sw group always took longest, the UL bp group always took the least time; the other two were always in between. For example, it took the UL bp group on average 45 seconds to resume breathing, while the BP sw group took twice that time. The UL bp recovered consciousness after 1 minute 45 seconds, the BP sw group took more than 4 times as long. The UL bp group knew who they were after just over two minutes after regaining consciousness, the BL sw group took nine and a half minutes. The UL bp group knew what year it was after 2 minutes 15 seconds, the BL sw group took over 20 minutes. In their introduction, the authors described ECT-induced memory loss as affecting “most patients to a degree, and some severely“….”A patient with marked ECT amnesia is likely to have substantial memory loss for the sequence of events immediately prior to treatment, and also a very partial and scattered amnesia, particularly for names, people and events, extending backwards in time perhaps for many months“.

So why doesn’t everybody get the least damaging form of treatment? Because psychiatrists prefer traditional methods? Because it requires a bit more skill to administer unilateral brief pulse effectively? Because they think the damage isn’t important? Because they think bilateral works better? Who knows? The fact remains that in Britain and America the vast majority of people undergoing ECT get bilateral brief pulse, one of the middle forms, and not the least dangerous form. Some hospitals in the US (and we are talking New York, not some remote parts) still give the most dangerous form, bilateral sine wave. And so too probably would some hospitals in the United Kingdom, if it wasn’t for a rare government intervention into an area which traditionally has been considered the exclusive territory of clinical judgement.

In 1980 a survey of ECT practice in Great Britain was carried out and  revealed that about half of all hospitals were still using sine-wave ECT.  Much of the equipment was out-dated, not regularly serviced, and operated by doctors who didn’t understand the controls. The day after the report of the survey was published, the government set up a working group chaired by psychiatrist John Pippard to look into the suitability, safety and maintenance of ECT equipment in the NHS.

The working group considered that the continued use of sine wave could not be recommended.

“Square waves are used for stimulation in electro physiology in all other fields and rise-times are in the micro-second range. Sine-wave are never used and their use in ECT appears to arise only from convenience”.

However, although the group advised immediate replacement of the very oldest models (some clinics were using machines that were 30 years old), hospitals were allowed as long as they liked to replace more modern sine wave equipment and a small number were still using sine wave ten years later. In the 1990s, psychiatrists in Scotland were still able to use sine wave ECT for the purposes of research.

This entry was posted in ECT in the UK, ECT machines, Electrical parameters. Bookmark the permalink.

One Response to How Britain switched to brief pulse ECT

  1. Cheryl Prax says:

    Thank you for researching these statistics. Keep up the good work! I would disagree though that unilateral is less damaging than bilateral. Unilateral justs gives a different kind of damage. Passing the current just over the right side of the brain causes damage to creative abilities, face recognition and insight to name a few.

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