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COGNITION AND ECT

This comprehensive overview discusses the various effects of Electroconvulsive Therapy (ECT) on cognition and memory, as presented by Iannis M. Zervas, M.D., from Athens University Medical School. It distinguishes between apparent and real impacts on memory, explores both positive and negative psychological outcomes, and examines factors affecting memory disturbances. The text details ECT's effects across distinct time phases, highlighting variations in cognitive ability, language, and attention. Key findings reveal significant variability in individual responses to ECT, calling attention to the underlying neurobiological mechanisms.

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COGNITION AND ECT

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  1. COGNITION AND ECT Iannis M. Zervas, M.D. Athens University Medical School

  2. ECT effects on cognition • Memory • Other

  3. ECT effects on memory • Apparent • Real

  4. Apparent effects-positive Memory improvement (!) Inaccurate psychologically but crucial from a psychiatric viewpoint

  5. Apparent effects-negative • Residual psychopathology (depression) • Drug effects (psych, anesthesia, other) • New psychosis (young, new onset) • Unmasking of dementia (old) • Subjective complaints (various motives)

  6. Real effects • Disorientation • Anterograde amnesia • Retrograde amnesia

  7. ECT Retrograde Anterograde remote recent

  8. Time course of memory disturbance • Acute • Subacute • Long-term

  9. ECT effects on non-memory cognitionAcute phase ( 0-7 hours) • General intelligence no change* • Perceptual function no change* • Attention -left side inattention -reduced speed in vigilance tasks *No change can be attributed to ECT

  10. ECT effects on non-memory cognitionSubacute phase (7-72 hours) • Intelligence no change or improved • Language verbal fluency may be affected • Perceptual/Visuospatial no change Motor function no change • Higher cognitive/ frontal no change

  11. ECT effects on non-memory cognitionMiddle subacute period (72 hrs -1 wk) • Intelligence improvement MMSE • Language improvement (rel. to depression) • Perceptual improvement • Attention/frontal no change (better in reaction time)

  12. ECT effects on non-memory cognitionLate subacute phase (1 wk -7 mo) • Intelligence improved (or no change due to ECT) • Language no change (due to ECT) • Perceptual improved (normalized depr. changes) • Motor improved ( trend) • Attention/frontal improved mental shifts no change in vigilance

  13. Memory disturbance Acute phase • Postictal • Interictal

  14. Acute memory disturbance • Postictal

  15. Acute memory disturbance • Interictal

  16. Subacute memory disturbance

  17. Memory effects Large inter-individual variability in: • Severity • Persistence (Reversibility) • Subjective tolerance / discomfort

  18. Factors affecting severity • Number of treatments • Frequency • Stimulus intensity • Electrode placement • Waveform • Oxygenation • Medications

  19. Factors affecting persistence • Prolonged post-ictal disorientation • Pre-ECT cognitive impairment • Probably age, neurological illness (e.g. Parkinson’s disease) • other obvious factors never studied ( i.e. substance abuse, medications, cardiac output status, etc)

  20. Attempts to ameliorate • Non-pharmacological methods ( schedule, oxygen, electrode placement, etc) • Various pharmacological methods

  21. ACTH dexamethasone naloxone vasopressin T4 TRH physostigmine caffeine Ca++ channel blockers piracetam pramiracetam inositol ergoloid mesylates herbal preparations ECT memory disturbancePharmacological attempts

  22. Memory systems involved in ECT with related brain structures

  23. Immediate / short-term memory (working memory) • Prefrontal cortex involved; Medial temporal lobe lesions spare this subtype • Dysfunctions after course of ECT (patients learn OK but forget fast) • Returns to baseline after a few weeks • Old patients more sensitive plus difficulty to learn new material. In 6 months no difference with younger.

  24. Declarative memory*New learning (anterograde amnesia) • Transitory difficulties in retaining new information and in recognizing or retrieving information learned some time previously • Increases with increasing number of treatments • Not associated with global cognitive dysfunction • Recovers within a few weeks after ECT *conscious recollection of facts and events, autobiographical or public

  25. Declarative memoryRemote memory (Retrograde amnesia) • Deficits in recall of autobiographical facts and events learned before ECT • Temporal gradient ( more so for events within the year prior to ECT) • Worse with bilateral • Worse with sinewave treatments • Reversible by 3 -6 months

  26. Non-declarative memory* No change includes • procedural learning ( neostriatum) • classical conditioning ( amygdala, cerebellum) • perceptual priming (cortical areas) Implicit memory** No change *non-conscious recollection of performance **non-conscious ability to learn spatial and temporal data

  27. Neurobiological correlates • Transient disruption of mechanisms for consolidation, retention, maintenance • Disruption of LTP related to persistence of stimuli, specificity /plasticity, associative organization • Possibly causes massive long-term induction of potentiation and saturates synaptic strengths obstructing formation of new memories • Time course of memory disturbance coincides with LTP disruption • Related to mesial temporal lobe; less affected by bifrontal treatments

  28. Neurochemical correlates • ECT inhibits activity of central cholinergic system= decrease in cholinergic transmission • Excessive release of excitatory amino acids and activation of their receptors • Ketamine ( NMDA antagonist) may be better alternative for anesthesia

  29. In support ofMedial Temporal Lobe (MTL)Dysfunction in ECT memory disturbance • role of MTL in memory • low seizure threshold in hippocampus • LTP disruption (ECS)is a hippocampal process • theta activity in left frontal and temporal sites associated with greater retrograde amnesia for autobiographical information

  30. In support of involvement of Prefrontal Cortex (PFC)in ECT memory dysfunction • Most profound physiological effects of ECT found in PFC-reductions in CB, -reductions in metabolic rate, -EEG slow wave activity • Retrograde amnesia greater for public events ( PFC) not autobiographical (hippocampus) • Tests of frontal lobe function can co-vary with tests of retrograde amnesia

  31. SUMMARY • ECT affects selectively memory parameters • There is large inter-individual variability • Memory disturbance is not related to clinical effects on depression

  32. SUMMARY • Memory disturbance is in general reversible • In some cases some retrograde amnesia for sporadic events (public mainly) may persist • Both mesial temporal lobe and prefrontal cortex (lowest seizure threshold in brain) have been implicated in memory trouble

  33. CONCLUSION • One should keep in mind that for most patients memory improves • Cost-benefit analysis for the patient • Simple measures can contain disturbance • Memory parameters should be monitored systematically - best to acknowledge and support / educate patient and family

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