Clinical Trial Details
— Status: Enrolling by invitation
Administrative data
NCT number |
NCT04040062 |
Other study ID # |
19-005605 |
Secondary ID |
|
Status |
Enrolling by invitation |
Phase |
N/A
|
First received |
|
Last updated |
|
Start date |
June 25, 2019 |
Est. completion date |
October 2025 |
Study information
Verified date |
May 2023 |
Source |
University of California, Los Angeles |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Interventional
|
Clinical Trial Summary
This study will analyze the feasibility, safety, and tolerability of administering repetitive
Transcranial magnetic stimulation(TMS) at frequencies other than standard 10 Hz. This study
will enroll 10 subjects who will undergo one quantitative electroencephalograph, one TMS
procedure to determine the appropriate frequency and intensity for treatment, weekly
mood/symptom assessments, and up to 30 TMS treatments. Subjects will be asked to participate
for up to 6 weeks.
Description:
The therapeutic benefit of repetitive Transcranial Magnetic Stimulation (rTMS) for the
treatment of Major Depressive Disorder (MDD) is thought to depend upon engagement of brain
functional networks (FNs). Engagement is dependent upon an interaction between the rTMS
stimulation frequency and the preferred oscillatory frequency of the target network for that
individual. We report here on a novel method to interrogate the left dorsolateral prefrontal
cortex (DLPFC) treatment target to identify the optimal frequency for engagement of the
frontoparietal control network (FCN) for each individual. 23 subjects with MDD were
stimulated with 40 pulse rTMS trains at frequencies varying from 3-17 Hz at 0.2 Hz
increments, plus a separate intermittent theta burst (iTBS) stimulation, for a total of 70
frequency interrogations. FN engagement was assessed using continuous high-density array
TMS-EEG recordings and measurement of the change in the density of the spectral correlation
coefficient (SCC) between left DLPFC and other brain areas following each interrogation. All
subjects had one or more frequency bands that showed high SCC values across multiple FNs,
regardless of the frequency of interrogation. Those subjects who showed clinical response to
10 Hz rTMS showed increases in SCCD over FCN connections across in response to 10 Hz
interrogation, but not in response to interrogation in other bands. There was a strong
association between the increase in SCCD in FCN and degree of improvement in depressive
symptoms after both 2 and 6 weeks of treatment. These findings suggest that SCC density may
be useful for identifying rTMS stimulation frequencies that are associated with therapeutic
benefit in MDD. This study will examine the feasibility using these findings to determine if
SCC-determined rTMS treatment can benefit subjects with Major Depressive Disorder.
INTRODUCTION AND RATIONALE
Repetitive Transcranial Magnetic Stimulation (rTMS) has been reported to relieve symptoms of
Major Depressive Disorder (MDD) when administered at a number of different stimulation
frequencies: 1, 5, 10, 15, 18, and 50 Hz (theta burst stimulation, or TBS) all have reported
to provide clinical benefit. It is difficult to compare the efficacy of these different
frequencies of stimulation because of differences in study design and limitations of sample
size, but there is significant evidence of efficacy for each of these frequencies when
applied to one or more stimulation targets.1 There have not been head-to-head studies to
compare different stimulation frequencies in individual subjects to determine whether
individuals have similar clinical responses to more than one frequency of stimulation.
One feature that is shared by all frequencies of rTMS is that while stimulation is ongoing,
both neuronal spiking and ongoing oscillations are synchronized to the frequency of
stimulation (Fröhlich and McCormick, 2010 ; Thut et al., 2011 ). This modulation of cerebral
oscillatory activity is hypothesized to underlie the therapeutic effects of rTMS for MDD. ,
Entrainment of brain oscillations has been shown to modify brain activity in a variety of
functional networks (FNs), with changes in oscillations associated with alterations in task
performance, local oscillatory activity, connectivity patterns and in the case of motor
networks, corticospinal coupling.
Different frequencies of rTMS stimulation have distinct effects on FN engagement and task
performance. These differential effects are consistent with the fact that FNs have one or
more preferred resonant frequencies that mediate connectivity both within and across networks
(Hacker et al., 2017 , , , The effects of rTMS stimulation depends upon the interaction
between the frequency of stimulation and the ongoing oscillatory activity of the target
FN(s): the oscillatory pattern of the specific brain region being stimulated (as measured
with electroencephalography [EEG]) is a major determinant of rTMS engagement with the
associated FN(s)3, and the effects on network performance.
The frontoparietal control network (FCN) is of particular interest in MDD because it is
dysregulated in MDD, with the degree of dysfunction related to severity of depressive
symptoms. The most commonly used neuroanatomic rTMS stimulation target is left dorsolateral
prefrontal cortex (DLPFC), which is a critical hub of the FCN. Furthermore, the FCN plays a
crucial role integrating the function of multiple other FNs. , , 10 Hz is the most commonly
rTMS stimulation used to stimulate the left DLPFC target, but it has not been established
that this frequency is optimal for engaging the FCN. Multiple stimulation frequencies have
differential effects on the FCN, changing FCN interactions with default mode network (DMN)
from excitatory to inhibitory. This finding is consistent with the fact that adjusting the
frequency of stimulation affects which nodes within a single FN are engaged, , the extent to
which rTMS stimulation engages local vs. distant network modules, and selectively alters the
engagement between a FN and an affiliated brain region. FCN connectivity is known to be
mediated by multiple frequencies ranging from 2 Hz (delta band) though 20 Hz (beta band)
(Johnson et al., 2019 ; Lopez et al., 2019 ; Cooper et al., 2015 ; 18).
The present study was performed to determine whether it was possible to identify differential
effects of rTMS treatment frequency on engagement of the FCN during rTMS treatment of MDD,
through examination of frequency coupling across a broad spectrum of stimulation frequencies
within the FCN. It was recently reported that changes in whole-brain spectral connectivity in
the frequency band (alpha spectral correlation, or SC) from pre- to post- the first session
of 10 Hz rTMS applied to left DLPFC predicted outcome from a course of 30 rTMS treatments. In
the current study, we examined spectral correlation across a broad frequency spectrum
following a series of rTMS "interrogations" ranging from 3 Hz to TBS. This allowed us to
generate a spectral correlation coefficient (SCC) across this frequency spectrum and
determine which frequencies of stimulation would lead to increased SCC within the FCN. This
study hypothesizes that: 1) each subject's frequency response pattern would show one or more
distinct frequencies of stimulation that generated increased SCC; 2) these frequency response
patterns would differ across subjects, but be highly reproducible within subjects over a
course of rTMS treatment; and, 3) those subjects with concentrated increases in FCN SCC
(increased SCC density) following 10 Hz interrogation would be more likely to show clinical
response to 10 Hz rTMS treatment.
STUDY OBJECTIVE
The primary objective of this study is to demonstrate feasibility of rTMS treatment for
depression at stimulation frequencies other than 10 Hz. Objectives:
1. to determine if each subject's frequency response pattern shows one or more distinct
frequencies of stimulation that generated increased SCC;
2. to determine if these frequency response patterns differ across subjects; and,
3. To gather pilot data for an extramural funding application to investigate the efficacy
of rTMS treatment at individualized stimulation frequencies as an alternative to the
standard 10 Hz protocol.