Transcranial Magnetic Stimulation in Neuropsychiatry
Transcranial magnetic stimulation (TMS) is an exciting new technology in which a rapid, brief magnetic pulse induces a secondary current in brain tissue. In addition to being a novel means of brain stimulation, it is unique in that it can be used to study brain neurophysiology and may have therapeutic applications for a number of neuropsychiatric disorders. TMS has been a rapidly growing subject of research since its initial development in 1985 and has been used by researchers from multiple disciplines (e.g., neurologists, neuroscientists, physicists, psychiatrists, and psychologists).
Because TMS is a technology with multiple applications, any book reviewing this topic has the challenge of meeting the needs of readers with differing interests. This book is a comprehensive yet basic and readable TMS primer covering a broad spectrum of issues in TMS research, and it will likely serve the needs of readers from multiple disciplines.
The book progresses logically from the historical origins of TMS, reviewed by the editors, to the physics involved in this technology, reviewed by Dr. Bohning. The overview of TMS physics begins with the basics; however, the discussion of complex mathematics is likely more than most readers require. Clearly there was an attempt to combine information for those wishing to become proficient in using TMS and those seeking a basic understanding of this technology and its potential future role in neuropsychiatry.
Drs. Ziemann and Hallett have authored an impressive, clearly presented review of the basic neurophysiological studies that are possible with TMS. Although much of the current interest in TMS has focused on potential therapeutic benefits, this chapter is very important in describing the range of applications for TMS in studying basic brain physiology. These techniques can be useful in increasing our understanding of neurophysiology in both normal subjects and those with neurologic and psychiatric disorders.
Dr. Belmaker and colleagues review the use of TMS to study mood disorder models in animals. Responses to TMS stimulation are compared with those of electroconvulsive shock studies (an animal model for ECT in humans). This review is brief, owing to the limited number of studies to date. In a separate chapter, the significant potential role of TMS in cognitive neuroscience is addressed in a review of TMS as a brain mapping tool.
Drs. Lorberbaum and Wasserman offer an essential, practical review of safety issues for both single-pulse and repetitive TMS (rTMS). Seizure induction, the primary safety concern in using rTMS, is reviewed in terms of experience to date and guidelines for minimizing seizure risk.
The use of TMS in clinical disorders is reviewed for hypokinetic movement disorders (primarily Parkinson's disease), epilepsy, depression, bipolar disorder, anxiety disorders, developmental stuttering and Tourette's syndrome, and schizophrenia.
To date, the therapeutic role of TMS has been best studied in depression. However, many of the studies have varied in design, stimulation parameters, and type of TMS used. The reference charts provided in the review of TMS in major depression by Drs. Lisanby and Sackeim are very useful for comparing this broad range of studies. Another practical feature of this review is a figure displaying the various sham conditions that have been employed, since these are difficult to understand through a verbal description alone. Understanding the type of sham used in controlled studies is important because more recent data suggest that some sham manipulations may be partially active.
The remaining chapters review TMS in other clinical disorders. The authors clearly present the limited research available in these areas and discuss future directions for research.
Dr. George and colleagues review the use of TMS in combination with various neuroimaging procedures and discuss the outlook for combining these technologies. The book concludes with a discussion of rTMS and future therapeutic applications by Drs. Post and Speer.
This book is very readable, is authored by leading researchers in multiple areas of TMS research, and has thorough listings of TMS references, most very recent. It is an excellent resource for understanding the broad range of TMS research performed to date and will likely be useful to both experienced researchers and interested novices.
Dr. Sampson is Instructor and Associate Director for TMS in the Neuropsychiatric Therapeutic Procedures Program, Mayo Medical School, Rochester, MN.
