The left anterior right temporal (LART) placement for electroconvulsive therapy: A computational modelling study

Electroconvulsive Therapy With Brain Cyst: A Simulation Study

INTRODUCTION

Electroconvulsive therapy (ECT) is effective in treating severe depression and other neuropsychiatric disorders, but how the presence of an anatomical anomaly affects the electrical pathways between the electrodes remains unclear. We investigate the difference in electric field (E-field) distribution during ECT in the brain of a patient with an arachnoid cyst relative to hypothetical condition where the cyst was not present.

METHODS

Magnetic resonance imaging scans of the head of a patient with a large left frontal cyst were segmented to construct a finite element model to study the E-field distribution during ECT. Five electrode configurations were investigated: right unilateral, left unilateral, bifrontal, and bitemporal and left anterior right temporal. The E-field distributions for all montages were compared with a hypothetical condition where brain tissue and electrical conductivity from the right frontal region was mirrored across the longitudinal fissure into the cyst.

RESULTS

Differences in mean E-field and 90th percentile E-fields were mainly observed in brain regions closest to the cyst including the left inferior frontal gyrus and left middle frontal gyrus. This trend was most pronounced in montages where the electrodes were closest to the cyst such as left unilateral and bitemporal.

CONCLUSION

The presence of a highly conductive cyst close to the ECT electrode tended to attract current into the cyst region, altering current pathways, with potential implications for therapeutic efficacy and safety. Placing electrodes farther away from the cyst is likely to minimize any effects on the E-field distribution and potentially clinical outcomes.

The utility of the Sydney Melancholia Prototype Index (SMPI) for predicting response to electroconvulsive therapy in depression: A CARE Network study

An enhanced understanding of clinical predictors of positive ECT outcome could assist with the decision to prescribe ECT for select patients. Reliable predictors of ECT response such as psychotic symptoms and age have been identified, however, studies of melancholia and ECT response have been inconsistent. The Sydney Melancholia Prototype Index (SMPI) is a clinical measure designed to differentiate melancholic and non-melancholic depression. This study aimed to investigate whether melancholic depression (as measured by the clinician rated version of the SMPI) predicted a better response to ECT than non-melancholic depression. The study included data collated from four participating sites in the Clinical Alliance for ECT and Related treatments (CARE) network. The primary outcome was response (>50% improvement) on the Montgomery Asberg Depression Rating Scale (MADRS) and the secondary outcome was raw change in MADRS score. Of the 329 depressed patients included in the study, 81% had melancholic features and 76% met criteria for clinical response. SMPI defined melancholia was associated with older age, higher pre-treatment mood scores and presence of psychosis. Melancholia as defined by the SMPI, however, did not significantly predict either clinical response or overall mood improvement with ECT in multivariate analyses. Instead, older age, greater pre-treatment depression severity and the use of bifrontal compared to right unilateral ultrabrief ECT were significant predictors of mood improvement. Path analysis showed that higher pre-treatment mood score and older age were independently associated with mood improvement with ECT.

The anticholinergic burden is not associated with cognitive impairments in patients treated by electroconvulsive therapy for treatment-resistant depression

BACKGROUND

Electroconvulsive therapy (ECT) is the most effective non-pharmacological treatment for treatment-resistant depression (TRD) but can expose to transient cognitive impairments. Understanding factors underlying these cognitive side effects is important. This study investigated the impact of anticholinergic treatments on cognitive performances after ECT courses for TRD in naturalistic condition.

METHODS

Impact of anticholinergic burden (Anticholinergic Impregnation Scale, AIS) on cognitive changes (Montreal Cognitive Assessment, MoCA) adjusted on depression level (Montgomery and Asberg Depression Scale, MADRS) was investigated in 42 patients who received an ECT course between 2017 and 2020 for unipolar or bipolar TRD. Collection of daily treatments given during ECT was carried out via the computerized traceability of treatments validated by nurses.

RESULTS

Among the 31 treatments identified with an anticholinergic score, which represent only 38% of total treatments, the three most frequently given treatments were Lorazepam (47%), Venlafaxine (36%) and Cyamemazine (26%). Delayed recall was the most frequently impaired cognitive function after ECT courses. Using logistic regression, we found no association between the anticholinergic burden and the decrease in cognitive scores after ECT courses, adjusted on MADRS score evolution (p > 0.1). Conversely, improvement in MADRS scores were correlated with improvement in attention MoCA subscores.

LIMITATIONS

This is a retrospective monocentric study with a moderate sample size using anticholinergic scales to calculate the anticholinergic burden without plasma dosage.

CONCLUSION

Anticholinergic treatments did not seem to explain ECT-related cognitive impairments. This warrants further large prospective investigations including different measures of anticholinergic burden.

Dosing methods in electroconvulsive therapy: should the Scandinavian time-titration method be resumed?

AIM

To describe and evaluate the different dosing methods in ECT, and bringing back into focus the Scandinavian time-titration method.

METHOD

A narrative, unsystematic, and selective review and discussion.

RESULTS

There are five dosing methods: 1) The Scandinavian time-titration to tonic convulsion, using low-frequency pulses and a long maximal pulse train duration, was highly efficacious with right unilateral (RUL) ECT, comparable to bitemporal (BT) ECT. However, the device used went out of production in the 1990s. Because US devices until 1990 had a short maximal pulse train duration, time-titration went out of use. 2) Fixed high dosing at 50-100% of the device's maximal output, and 3) Formula-based dosing, initially the Age method, long prevailed in USA. Later, the Half-Age method was introduced for BT ECT. 4) Charge-dosing as a multiple of titrated seizure threshold (ST) demonstrated RUL and BT ECT to have comparable outcomes when dosed about six and two times the ST, respectively. 5) Dosing from benchmark is based on a high dose at the first session, to ensure a high peak heart rate and tonic-clonic convulsions. In later sessions the lowest dose producing similar outcomes is chosen.

CONCLUSIONS

No dosing method is documented superior to the others. Seizure threshold-based and benchmark dosing seems to be more accurate than fixed high and formula-based dosing. However, time-titration dosing makes it possible to adjust the dose at every session, and may be the most efficient method.

Effects of modifying the electrode placement and pulse width on cognitive side effects with unilateral ECT: A pilot randomised controlled study with computational modelling

BACKGROUND

The electrode placement and pulse width for electroconvulsive therapy (ECT) are important treatment parameters associated with ECT related retrograde memory side-effects. Modification of these parameters with right unilateral (RUL) ECT may have utility for further reducing these side-effects.

OBJECTIVE

This study explored use of the frontoparietal (FP) placement for reducing retrograde memory side effects with ECT. We hypothesised that superior retrograde memory outcomes would occur with FP compared to temporoparietal (TP) placement and with ultrabrief (UB: 0.3 ms) compared to brief pulse (BP: 1.0 ms) width ECT.

METHODS

In this randomised cross-over, double-blinded study, participants received a single treatment of BP TP, BP FP, UB TP and UB FP ECT. Neuropsychological testing was conducted prior to and immediately following each treatment. Computational modelling was conducted to explore associations between E-fields in regions-of-interest associated with memory.

RESULTS

Nine participants completed the study. The FP placement was not superior to TP for retrograde memory outcomes. For both electrode placements UB pulse width was associated with significantly better visual retrograde memory compared to BP (p < .05). With TP ECT, higher E-fields in regions-of-interest were significantly associated with greater visual retrograde memory side-effects (hippocampi: r = -0.77, p = .04; inferior frontal gyri: r = -0.92, p < .01; middle frontal gyri: r = -0.84, p = .02).

CONCLUSIONS

Modification of pulse-width had greater effects than electrode placement for reducing retrograde memory side-effects with RUL ECT. Preliminary findings suggested that higher E-fields may be associated with greater cognitive side-effects with ECT.