Brigham and Women’s Faulkner Hospital recently opened an autonomic testing lab, which serves as the main autonomic testing facility for the Brigham and Women’s Health Care (BWHC) family. “BWFH’s new autonomic lab is a unique resource, as there are not many autonomic labs in the Northeast that offer this type of testing, coupled with a team of trained physicians who can really decipher the results,” explains Sherman Zemler Wu, Director of Clinical Program Development at BWFH.
Autonomic testing assesses autonomic nervous system integrities by eliciting sweating, respiratory, heart rate, and blood pressure responses. The testing done at BWFH’s autonomic lab is not invasive, but rather administered to elicit and monitor a patient’s autonomic responsiveness. “The blood pressure and heart rate monitoring during autonomic testing are unique in that the measurements are taken on a continuous beat-to-beat, second-by-second basis,” explains Jeffrey Liou, DO, who heads up the autonomic lab. “Such continuous measurements allow us to make diagnoses that otherwise would have been missed in other clinical settings using conventional measuring equipment.”
Liou states that tests measuring a patient’s heart rate variability and baseline electrocardiogram (EKG) are the first tests his staff will perform. “Your heart rate increases and decreases as you inhale and exhale,” says Dr. Liou. “One of the parameters we measure is how much the heart rate varies during deep respiration. Abnormality in heart rate variability can be the first sign of many autonomic disorders even before obvious symptoms manifest themselves.”
Other components of autonomic tests include a sympathetic skin response test, or sweat response test, in which electrodes are placed on a patient’s hands and feet to detect galvanic responses on the skin. This test screens whether a sweating response is present or not.
Valsalva maneuver testing involves patients blowing into a tube to elicit changes in blood pressure and heart rate.
Tilt table testing, the “core” of autonomic testing because it takes the most time, has a patient lie flat on his back then be rapidly tilted up to a 60 degree angle to record how blood pressure and heart rate compensate for such a maneuver. The patient will remain at this angle for 45 minutes. On certain patients with concerns for seizures, continuous EEG monitoring can be performed simultaneously with the autonomic testing. BWFH is the only hospital in the region that offers simultaneous EEG monitoring.
An active stand test is performed last and involves monitoring a patient’s physiologic parameters while having the patient stand up very quickly after the tilt table testing is completed. Active standing can elicit responses that may not show during the tilt table testing allowing the interpreting physician to diagnose entities such as initial orthostatic hypotension.
Autonomic specialists at BWFH’s autonomic clinic see patients who are often seeking answers to problems with lightheadedness, dizziness, fainting, abnormal sweating, neuropathy, and certain pain syndromes, as well as patients who were previously diagnosed with diseases such as Parkinson’s disease, multiple system atrophy, and diabetes. “Autonomic testing is important because it can help clarify the diagnosis and provide objective evidence for a patient’s autonomic dysfunction,” Liou states. “Many patients go for years without an explanation for their symptoms, often hitting a wall in trying to determine their exact condition or diagnosis.”
The testing done at BWFH will help clinicians evaluate patients with possible autonomic problems so that patients can work with their healthcare team to determine a treatment plan that will alleviate their symptoms and improve their quality of life. Autonomic testing also provides patients who have already been diagnosed with autonomic dysfunctions a means to monitor their disease progression and tailor treatment to the degree of their dysautonomia. For instance, results of autonomic testing can help guide whether a specific blood pressure medication is working or whether the medication dosage needs to be adjusted.
Autonomic lab program director Jeffrey Liou comes to BWFH with a rich background in the neurosciences. He previously majored in biomedical engineering at Northwestern University, completed his Master’s program in bioethics at Case Western Reserve University, did his neurology residency and sleep medicine fellowship at Dartmouth-Hitchcock Medical Center before practicing as a sleep physician in St. Paul, Minnesota. In 2011, Dr. Liou completed a year-long clinical neurophysiology fellowship with Dr. Roy Freeman at Beth Israel Deaconess Medical Center focused on diagnosis and treatment of autonomic disorders. Dr. Liou was asked specifically by BWFH’s administration to help create an autonomic testing facility on the BWFH campus. “Comprehensive autonomic evaluation is available only at a few select academic centers in the country. Having this unique service available to our patients and care providers,” Liou reflects, “allows us to not only offer a complete spectrum of premier neurologic services but also raise the standard of care here at BWFH.”
If you, your primary care physician, cardiologist, or neurologist would like more information on BWFH’s autonomic testing services, please call 617-983-7580.
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