Cognitive side-effects from electroconvulsive therapy (ECT) can be distressing for patients and early detection may have an important role in guiding treatment decisions over the ECT course. This prospective study examined the utility of an early cognitive screening battery for predicting cognitive side-effects which develop later in the ECT course. The screening battery, together with the Mini Mental Status Examination (MMSE), was administered to 123 patients at baseline and after 3 ECT treatments. A more detailed cognitive battery was administered at baseline, after six treatments (post ECT 6) and after the last ECT treatment (post treatment) to assess cognitive side-effects across several domains: global cognition, anterograde memory, executive function, speed and concentration, and retrograde memory. Multivariate analyses examined the predictive utility of change on items from the screening battery for later cognitive changes at post ECT 6 and post treatment. Results showed that changes on a combination of items from the screening battery were predictive of later cognitive changes at post treatment, particularly for anterograde memory (p < 0.01), after controlling for patient and treatment factors. Change on the MMSE predicted cognitive changes at post ECT 6 but not at post treatment. A scoring method for the new screening battery was tested for discriminative ability in a sub-sample of patients. This study provides preliminary evidence that a simple and easy-to-administer measure may potentially be used to help guide clinical treatment decisions to optimise efficacy and cognitive outcomes. Further development of this measure and validation in a more representative ECT clinical population is required.
Electroconvulsive therapy (ECT) is widely considered an essential treatment for severe major depression, with research showing robust efficacy, even in treatment resistant patients (Husain et al., 2004 and Heijnen et al., 2010). Despite such clear evidence for effectiveness, there is still much controversy and public misunderstanding about the treatment (Chakrabarti et al., 2010), driven at least in part by the risk of cognitive side-effects. Although cognitive side-effects are frequently evident immediately after ECT, particularly for memory for newly learned information (i.e., anterograde memory), research studies have consistently demonstrated that these are mostly short lived and tend to resolve in the months following treatment (Semkovska and McLoughlin, 2010 and Verwijk et al., 2012). Nevertheless, there remain concerns regarding the risk of longer term cognitive effects, with some studies showing persistent subjective memory complaints (Squire and Slater, 1983 and Berman et al., 2008) and deficits in autobiographical memory (Ng et al., 2000, McCall et al., 2002 and Sackeim et al., 2007) after treatment has ended. Variation in the severity and duration of cognitive side-effects has been shown to be contingent upon the ECT treatment approach used (Sackeim et al., 2007, Semkovska and McLoughlin, 2010 and Loo et al., 2012), with more effective treatment approaches (e.g., higher dosage, bilateral electrode placement) tending to result in poorer outcomes. Early detection of emerging cognitive side-effects during the ECT course is, therefore, important so adjustments to the treatment approach (e.g., the wider spacing of treatments) can be made to minimize later side-effects.
Routine assessment of cognition during a course of ECT has been suggested in the practice guidelines of many professional organizations (American Psychiatric Association, 2001 and Scott, 2004). Despite such guidelines, there is currently no consensus regarding the cognitive measures that should be used, or when they ought to be administered to best monitor cognitive effects of treatment. Impediments to widespread, routine, formal assessment in clinical practice include time restraints, lack of adequate training for administration of neuropsychological measures, and patient attrition and resistance. For example, the administration of a standardized neuropsychological test of anterograde memory (i.e., word list learning task), typically involves at least 30 min administration time (including 20–25 min delay) and formal administrator training. In the absence of consensus for appropriate measures and the aforementioned constraints in clinical practice, important treatment decisions made during the ECT course, including switching of electrode placement, changes in electrical dose, and spacing of treatments, are often made without formal assessment or at best with brief “bedside” cognitive tests, such as, the Mini Mental State Examination (MMSE; Folstein et al., 1975). The concern is that these measures may be effective in detecting gross cognitive impairment but may not be sensitive to early cognitive changes which are predictive of later cognitive impairment (Porter et al., 2008). The development of a brief, simple, easy-to-administer measure, which is sensitive to early cognitive changes following ECT, would therefore be of significant utility for clinical practice in informing such decisions.
