Variability and Stability of TMS Treatment Targets for PTSD Restricted; Files Only
Teye-Botchway, Lois (Spring 2023)
Abstract
Transcranial Magnetic Stimulation (TMS) is a non-invasive neuromodulation treatment shown to be moderately effective for Post-Traumatic Stress Disorder (PTSD). However, it is hypothesized that treatment efficacy can be improved by individualizing TMS targets using neuroimaging. Here, we aim to determine the variability of the DLPFC target between individuals, the variability between positive and negative target definitions, and the stability of the target across states after fear neurocircuitry task activation. In this ongoing sham-controlled TMS clinical trial, pre-TMS resting-state functional connectivity (RSFC) was used to define the area within the rDLPFC most strongly connected with the right amygdala for each participant. A second RS scan was collected in the same visit after the amygdala was activated by fMRI tasks. Neuroimaging data for seventeen patients were analyzed, which indicated significant variability in target location between participants (F(1,16)=3005, p<0.001, ηp2=0.99). Results showed significant differences in the positive and negative target definitions (F(1, 16) = 6.2, p = 0.02, ηp2=0.28). However, the change in target location between RS scans 1 and 2 was not significant (F(1, 16) = 0.8, p = 0.38, ηp2=0.05), showing that the target remained stable after activation. The results suggest the importance of individualized targeting and the importance of further evaluation of negative- versus positive correlated DLPFC targets in the future. The lack of change in target location after amygdala activation suggests the rDLPFC target is stable within each individual. This has implications for combining TMS with trauma-focused therapy, in which the amygdala and fear neurocircuitry is activated. However, the small sample size limits the generalizability of the results, and further research with a larger participant pool is needed to confirm these findings.
Table of Contents
INTRODUCTION 1
WHAT IS PTSD? 1
WHAT ARE THE TREATMENTS FOR PTSD? ARE THEY EFFECTIVE? 2
WHAT IS THE NEUROBIOLOGY OF PTSD AND PTSD TREATMENT NON-RESPONSE? 3
WHAT IS TRANSCRANIAL MAGNETIC STIMULATION? 5
HOW IS THE TARGET FOR TMS DEFINED? 5
WHAT IS INDIVIDUALIZED TARGETING, AND WHY IS IT IMPORTANT? 6
HOW ARE MRIS USED FOR TARGETING? 7
HOW IS CORRELATION DATA USED TO FIND TARGETS? 8
WHAT AREA IS TARGETED FOR PTSD? WHY IS IT EFFECTIVE? 8
WHAT IS DLPFC TARGET STABILITY? 10
RESEARCH QUESTIONS, STUDY DESIGN AND HYPOTHESES 10
METHODS 12
PARTICIPANTS 12
MRI SCAN PARAMETERS 13
TMS TARGETING 14
TMS PROTOCOL 14
DATA ANALYSIS 15
RESULTS 16
DISCUSSION 17
THE DLPFC TARGET VARIES BETWEEN PARTICIPANTS 17
POSITIVE AND NEGATIVE TARGET DEFINITIONS VARIED SIGNIFICANTLY 19
THE DLPFC TARGET IS STABLE 19
LIMITATIONS 20
FUTURE DIRECTIONS 21
CONCLUSION 22
REFERENCES 24
TABLES AND FIGURES 27
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File download under embargo until 19 May 2025 | 2023-04-10 12:15:01 -0400 | File download under embargo until 19 May 2025 |
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