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Thursday, August 23, 2007

Cognitive side effects of electroconvulsive therapy in adolescents

No severe cognitive side effects of ECT used on adolescents could be demonstrated. ECT in adults causes memory complaints, retrograde and anterograde amnesia. The tests used in trials with adolescents are limited in measuring these side effects. Moreover there are no prospective studies on this subject with adolescents and the studies discussed have a small number of subjects with possible lack of statistical power.

Publications about ECT and side effects in adolescents
So far I was able to find four articles about cognitive side effects of ECT in adolescents. They belonged to two different research groups.
From the department of psychiatry of the university of Michigan there is a study in which 5 of 11 adolescents treated with ECT were tested both before and 1-5 days after the last ECT. The neuropsychological tests revealed a significant decline in attention, concentration and long-term memory search. In another publication by this group they collected retrospective data resulting from clinical care with naturalistic follow up of 16 adolescents treated with ECT for mood disorder. Cognitive tests administered before ECT were compared with results at 7 days following the last treatment as well as another testing at 8 months after the last treatment.

Cognitive side effects 1
Testing directly after ECT and compared to the test before ECT yielded significant impairments of concentration, attention, verbal- and visual delayed recall, and verbal fluency. A complete recovery of these functions was noted at the second post-ECT testing. There were no impairments of motor strength and executive processing, even during the early period post ECT.

These studies had little focus on memory disturbances with ECT in adolescents.
The other group from Paris, France focused on memory function. 20 adolescent patients treated with ECT during the period 1987-1996 were contacted for follow up. For various reasons only 10 could be included. Another 10 subjects comparable for sex, age, date and place of hospitalization and diagnosis were considered as a control group.
All subjects were given a battery of clinical and cognitive evaluations. The most important being the Wechsler Memory Scale and California Verbal Learning test , which assesses anterograde amnesia and verbal learning as well as Squire's Subjective Memory Questionnaire for subjective memory complaints.

Cognitive side effects 2
The ECT group did not differ significantly on all cognitive tests at an average of 3.5 years after the last ECT compared to the matched control group.

Lousy tests
Trouble is that all these tests are of no use for the memory effects of ECT at all. The Wechsler Memory test is like the original Wechsler Memory Scale, and provides only a rough estimate of overall memory functioning. The multidimensional index scores have not been shown effective in describing the nature or the pattern of memory deficits. The California Verbal Learning Test (CVLT) is a popular clinical and research test that claims to measure key constructs in cognitive psychology such as repetition learning, serial position effects, semantic organization, intrusion, and proactive inteference.

In an earlier article the lack of proper memory tests for testing retrograde and anterograde amnesia in adults treated with ECT is mentioned.

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