An unexpected observation during a diagnostic MRI brain scan may provide relief for people with medication-resistant, life-threatening depressive disorders.
People diagnosed bipolar disorder (BPD) who had diagnostic MRI brain scans, reported rapid mood elevation after the procedure.
The magnetic resonance imaging procedure was not intended to be therapeutic, but this unexpected finding led a team from Harvard directed by Michael L. Rohan, and including Rinah T. Yamamoto, Kenroy R. Cayetano, David P. Olson, Caitlin T. Ravichandran, Oscar G. Morales, Gordana Vitaliano, with Cornell colleagues Steven M. Paul and Bruce M. Cohen in developing Low Field Magnetic Stimulation (LFMS) that reproduces the rapidly oscillating (1 kHz, <1 V/m) electromagnetic field.
They evaluated this device’s potential to provide mood elevation to more than 40 people diagnosed with depression associated with bipolar disorder (BPD) and more than 20 people diagnosed with major depressive disorder in a randomized, double blind, controlled study.
Participants received a single, 20-minute treatment of 256 microsecond pulses separated by 1 millisecond, then Rohan’s team immediately evaluated mood using the Visual Analog Scale (VAS), the 17-item Hamilton Depression Rating Scale (HDRS-17), and the Positive and Negative Affect Schedule (PANAS) scales.
They found substantial mood improvement following LFMS electric stimulation throughout the cerebral cortex, compared with a sham “treatment” for both volunteer groups.
In fact, six weeks of Transcranial Direct Current Stimulation (tDCS) was equally effective as antidepressant Sertraline (Zoloft) for 120 participants diagnosed with major depressive disorder, reported University of São Paulo’s Andre R. Brunoni, Leandro Valiengo, Alessandra Baccaro, Tamires A. Zanão, Janaina F. de Oliveira, Alessandra Goulart, Paulo A. Lotufo, and Isabela M. Benseñor, with Paulo S. Boggio of Mackenzie Presbyterian University and Harvard’s Felipe Fregni.
Both treatments were more effective than either alone when Brunoni’s team combined Transcranial Direct Current Stimulation (tDCS) with Sertraline (Zoloft).
The typical current dose used in tDCS is a thousand times lower than the dose used in Electroconvulsive Therapy (ECT), and may enable neural connections to rewire, depending on the position of current flows, found City College of New York’s Marom Bikson and Abhishek Datta, with Peter Bulow of Columbia University, Seton Hall University’s Fortunato Battaglia, John W. Stiller of St. Elizabeth’s Hospital, Princeton’s Sergei V. Karnup, and Teodor T. Postolache of University of Maryland.
tDCS has also shown potential to improve learning and motor skill performance – with caveats.
One study demonstrated tDCS’s impact on improved word reading efficiency among 25 right-handed volunteers, due to increased left lateralization of the brain’s posterior temporal cortex (pTC), reported Georgetown’s Peter E. Turkeltaub with Jennifer Benson of University of Michigan, collaborating with Roy H. Hamilton and H. Branch Coslett of University of Pennsylvania and City College of New York’s Abhishek Datta and Marom Bikson.
The team asserted that these findings offer a low-cost, accessible treatment option for people with below-average reading skills and developmental dyslexia.
Likewise, tDCS brain stimulation during numerical learning over five days enhanced people’s ability to learn a new number system based on arbitrary symbols – with significant improvement enduring up to 6 months in a study by University of Oxford Roi Cohen Kadosh, with Sonja Soskic, Teresa Iuculano, Ryota Kanai, and Vincent Walsh of University College London.
However, these benefits came with costs when the team compared volunteers who received electrical stimulation to:
- Posterior parietal cortex, implicated in numerical cognition,
- Dorsolateral prefrontal cortex, involved in learning and memory.
The team also provided a “sham” treatment that caused no change in brain activity to another.
Volunteers who had the parietal area electrical stimulation learned the new number system more quickly than those who got sham stimulation.
However, the cost was slower reaction times when they applied the learned skill to novel tasks.
Those who received prefrontal stimulation were slower than the control group to learn the new numerical system, but they performed faster on the new test at the end of the experiment.
Skilled physical performance selectively improved with noninvasive Transcranial Stimulation (tDCS) among musically-untrained volunteers, but not for highly-trained musicians, found Hanover University of Music, Drama and Media’s Shinichi Furuya, Matthias Klaus and Eckart Altenmüller, with Michael A. Nitsche and Walter Paulus of Georg-August-University.
Further caveats come from University College London’s Vincent Walsh, who critiqued this and other studies, for potential shortcomings, including:
- Inadequate control experiments,
- Speculation about brain areas excited and inhibited by tDCS,
- Real-world relevance of small effects noted in lab experiments.
-*To what extent does electrical brain stimulation offer appealing therapeutic and performance benefits?
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