Prediction of the utility of a switch from unilateral to bilateral ECT in the elderly using treatment 2 ictal EEG indices.

BACKGROUND: The choice of whether to administer nondominant unilateral (UL) or bilateral (BL) ECT remains controversial. METHODS: A study in which moderately suprathreshold UL nonresponders at treatment 6 were randomized to UL or BL ECT offered the opportunity to explore whether ictal EEG indices at treatment 2 might predict response to UL ECT, and also which UL ECT nonresponders are likely to respond to BL ECT. RESULTS: We found that less postictal suppression in response to the second UL ECT stimulus was predictive of a poorer subsequent therapeutic response to UL ECT, but of a better therapeutic response if switched to BL ECT. A multivariate ictal EEG model was developed that had a significant capacity to differentiate those who will respond to UL ECT versus those who will not respond to UL ECT, but who will be therapeutic responders when switched to BL ECT. CONCLUSIONS: This study raises the possibility that ictal EEG indices at treatment 2 may identify situations when UL ECT is physiologically and therapeutically inadequate, and when BL ECT is likely to be more effective. The determination of whether such predictive physiologic models are of clinical utility for the prediction of outcome awaits further study.

Changes in seizure threshold over the course of electroconvulsive therapy affect therapeutic response and are detected by ictal EEG ratings.

Therapeutic effectiveness of electroconvulsive therapy is influenced by the degree to which the stimulus intensity exceeds the seizure threshold. However, the threshold rises variably over the treatment course, confounding maintenance of desired relative stimulus intensity. In 47 depressed patients, decreases in relative stimulus intensity between treatments 1 and 6 were associated with diminished therapeutic response at treatment 6 for unilateral (UL) ECT. A multivariate model including manual ratings of ictal EEG data predicted whether seizure threshold rose with 82% accuracy. The same EEG variables were also significantly related to therapeutic response. Thus, decreases in relative stimulus intensity over the ECT course affect the therapeutic potency of UL ECT. Further, ictal EEG indices have considerable potential for predicting such stimulus intensity changes and their effect on therapeutic outcome.

The relative ability of three ictal EEG frequency bands to differentiate ECT seizures on the basis of electrode placement, stimulus intensity, and therapeutic response.

Ictal EEG indices show promise for separating individual ECT seizures on the basis of treatment electrode placement (ELPL), relative stimulus intensity (Dose), and expected therapeutic response. One factor impeding the effective clinical implementation of ictal EEG indices for these purposes is uncertainty as to the relative utility of lower and higher frequency EEG activity. Recent articles are contradictory in this regard, but no data exist addressing this issue. As a result, we reanalyzed data from 44 subjects in two studies and compared the relative ability of ictal EEG data in three frequency bands to differentiate seizures as a function of ELPL, Dose, and therapeutic response. We found that the frequency band that best differentiated these groups depended on the EEG measure used, the temporal portion of the seizure, and whether ELPL, Dose, or therapeutic response was being compared.

Assessing diagnostic approaches to depression in medically ill older adults: how reliably can mental health professionals make judgments about the cause of symptoms?

OBJECTIVE: To evaluate the reliability of the DSM-IV approach and five other schemes for counting symptoms toward the diagnosis of depression in hospitalized medically ill older patients and to examine whether mental health professionals can reliably make judgments about the etiology (medical or psychological) of depressive symptoms. METHOD: A sample of 38 patients aged 60 years or older admitted to the general medicine, cardiology, or neurology services at Duke University Medical Center were evaluated for depression using a structured psychiatric interview and the Hamilton Depression Scale. Interrater reliability for the diagnostic schemes, for unstructured clinical diagnoses, and for determinations of the causes of individual depressive symptoms was assessed by three pairs of mental health professionals. RESULTS: Agreement between raters for structured diagnoses was high regardless of diagnostic strategy, with the DSM-IV approach being only slightly less reliable than the strict inclusive approach (Kappa 0.88 vs Kappa 1.0, respectively). For all diagnostic approaches, there was perfect agreement between raters for eight cases of major depression. Agreement for unstructured clinical diagnoses of depression (K = 0.50) was much lower than for the structured diagnoses. Agreement between raters on the etiology of individual depression criterion symptoms assessed by structured interview was greater than 80% for 14 of 19 symptoms. Correlation between raters' depression severity ratings on the Hamilton Scale using the DSM-IV etiologic approach was equivalent to that using the strict inclusive approach (0.98 vs 0.95, respectively). CONCLUSIONS: Mental health professionals can be trained to make judgments reliably about the cause (medical or psychological) of symptoms in hospitalized older medical patients. The "strict inclusive" and other diagnostic schemes for counting symptoms toward the diagnosis of depression have only marginal, if any, benefit compared with the current DSM-IV approach.