The threshold number of pulses in bilateral and unilateral ECT.

Using a low-energy brief-pulse stimulus, the threshold number-of-pulses required to produce a bilaterally manifested tonic-clonic seizure with unilateral and bilateral electrode placement was investigated. Unilateral placement required significantly fewer pulses; bilateral placement resulted in greater post-ictal confusion with no apparent advantage in clinical efficacy. A possible explanation in terms of intracerebral current density is proposed.