Safety and benefits of distance-adjusted prefrontal transcranial magnetic stimulation in depressed patients 55-75 years of age: a pilot study.
In contrast to the effects seen in younger adults, depressed elderly subjects have shown more modest antidepressant responses to transcranial magnetic stimulation (TMS). We theorized that higher stimulation intensities in older depressed subjects with prefrontal atrophy might be needed to stimulate underlying cortex. In an open design with patients on stable baseline medications, we treated 18 treatment-resistant elderly depressed subjects (mean age 61.2 +/- 7.3) with 15 rTMS sessions over 3 weeks. We adjusted the delivered TMS intensity to account for MRI measured prefrontal atrophy. The skull to prefrontal cortex distance increased with age, whereas the skull to motor cortex distance did not. All subjects tolerated the higher doses well. The average intensity used was 114% of motor threshold (MT) with a range from 103-141% MT. There was an average 35% decline over the 3 weeks in HRSD scores. After 3 weeks of treatment, 27% (5/18) met response criteria (> 50% improvement), with four of these five also meeting criteria for remission (exit Hamilton Depression Score < 8). These initial pilot findings support the need for blinded studies using prefrontal TMS in an elderly population, testing whether TMS, delivered at stimulation intensities calculated to overcome atrophy, is more effective than TMS without adjusting for atrophy.
Nahas
Ziad
Z
Brain Stimulation Laboratory, Institute of Psychiatry, Medical University of South Carolina, Charleston, SC 29425, USA. nahasz@musc.edu
Li
Xingbao
X
Kozel
F Andrew
FA
Mirzki
Dario
D
Memon
Mohammed
M
Miller
Kristen
K
Yamanaka
Kaori
K
Anderson
Berry
B
Chae
Jeong-Ho
JH
Bohning
Daryl E
DE
Mintzer
Jacobo
J
George
Mark S
MS
D000368:Aged; D001284:Atrophy / Q000473:pathology; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000628:therapy*; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D017397:Prefrontal Cortex / Q000473:pathology*; D012720:Severity of Illness Index; D012886:Skull; D011795:Surveys and Questionnaires; D050781:Transcranial Magnetic Stimulation / Q000295:instrumentation*