'Brain Waves' posts

SNI is leveraging communication tools that deliver information to patients, referring physicians and the public as a crucial part of providing care at the advancing edge of neu­rological knowledge. The goals of these tools are two-fold. One goal is to update established patients and their doctors regarding the latest developments in our programs and centers. The other is to lower the barrier for patients and physicians who are facing a new neuro­logical problem to discover tertiary subspe­cialty care.

A new SNI communication tool

Dan Rizzuto, Ph.D., director of SNI research, and John Henson, M.D., recently launched the SNI blog to complement other commu­nication efforts and to provide a communication outlet for the staff of SNI. The SNI blog offers brief notes about advances in neurological care provided in SNI’s centers, as well as news items about the institute that are of interest to our patients and referring physicians.

Blog content is more dynamic than Web content. Search engines are able to detect targeted key words within each entry, which helps direct highly relevant Web traffic to the blog. This aids in the dissemination of infor­mation to patients and physicians. Viewers also can subscribe to an e-mail notification system that will alert them to newly posted material.

Other SNI communication tools

The Winter 2010 edition of BrainWaves is now available online.

BrainWaves is the newsletter of the Swedish Neuroscience Institute. Published quarterly, BrainWaves provides information about neurological conditions treated at the Institute, and also profiles the programs, services, and new initiatives of the institute and its staff.

Also check out our past editions of the BrainWaves newsletter.

FROM BRAINWAVES: Since its introduction in 1982, transcranial doppler ultrasound (TCD) has evolved into a portable, multimodality, noninvasive method for real-time imaging of intracranial vasculature. The detection of cerebral microemboli is among the more remarkable capabilities of TCD. Emboli create countable signals in the ultrasound display due to the higher reflection of sound waves compared to the blood cells. Experimental models have shown a high sensitivity and specificity for detection of a variety of substrates, including thrombotic, platelet and atheromatous emboli.

Microembolic signals (MES) within the intracranial vasculature are most frequently identified in patients with large-vessel atherosclerotic disease, such as carotid stenosis. They have also been reported in intracranial arterial stenosis, arterial dissection, cardiac disease and atheroaortic plaque. Additionally, they have been seen in arteries distal to coiled aneurysms.

There is strong evidence that MES detection predicts future ipsilateral stroke risk in patients with symptomatic carotid stenosis (Markus HS, et al.; King A, et al.). A recent study of patients with asymptomatic carotid stenosis demonstrated that MES predicted subsequent ipsilateral stroke and TIA, and also ipsilateral stroke alone, and that it is helpful in selecting patients who will benefit from carotid endarterectomy.

Congratulations are in order for the Clinical Neurophysiology Laboratory for attaining Accreditation by the EEG Laboratory Accreditation board of ABRET. We are the first and only Lab to receive Accreditation in Washington State and one of only 10 labs west of the Mississippi. Accreditation means the Lab has met strict standards and is recognized as a place where patients and physicians can have confidence they are receiving quality diagnostics. Thanks for all the great work and CONGRATULATIONS to everyone on the team who made this possible!

-Colleen Douville

The neurophysiology laboratory at Swedish is a critical component to the Epilepsy program.

The Summer 2010 Edition of BrainWaves is now available online.

BrainWaves is the newsletter of the Swedish Neuroscience Institute. Published quarterly, BrainWaves provides information about neurological conditions treated at the Institute, and also profiles the programs, services, and new initiatives of the institute and its staff.

Also check out our past editions of the BrainWaves newsletter.

Essential tremor (ET) is the most common type of movement disorder, affecting approximate­ly four out of 1000 people, and is significantly more common, though less recognized, than Parkinson’s disease. ET affects men and women equally and is inherited as an autosomal-dominant condition in about 60 percent of cases.

Although often referred to as benign essen­tial tremor, it is hardly benign in patients who may not be able to write legibly, hold a glass of water or use a knife and fork. ET is primarily an action tremor of the upper extremities but may involve resting tremor of the head and neck and/or lower jaw, and also tremor of the voice. The latter may be so severe that speech becomes unintelligible.

Medication and surgical treatment options

Primidone and beta blockers are useful in re­ducing tremor in the early stages of ET, but as the tremor progresses, medical management often becomes less effective or side effects can prevent the use of adequate doses of medication. ET pa­tients then are candidates for surgical or radiosur­gical treatment.

The mainstay of the surgical treatment of ET is deep brain stimulation (DBS), in which an electrode is implanted in the ventral inter­mediate nucleus (VIM) of the thalamus. Neurosurgeons Peter Nora, M.D., and Ryder Gwinn, M.D., have been implant­ing DBS electrodes at Swedish Medical Center for several years. The treatment is effective, but it requires implantation of permanent hardware (wires and batteries) into the brain and chest wall. Patients who take anticoagulants or have severe cardio­vascular disease are not suitable candidates for DBS. These patients, however, may be candidates for radiosurgical treatment.

A new option for difficult-to-treat patients

Bilateral 8th cranial nerve tumors, also known as vestibular schwannomas or acoustic neuromas (see figure), are pathognomonic of a fascinating syndrome called central neurofibromatosis or neurofibromatosis type 2 (NF-2). NF-2 is a rare, autosomal-dominant disease with an incidence of 1 in 30,000 live births. The mechanism by which the genetic changes underlying NF-2 produce these tumors of a cranial nerve remains a mystery. Interestingly, two other associations are also sufficient to make a diagnosis of NF-2. These are unilateral VS at early age (< 30 years) plus two other specific lesions (meningioma, schwannoma other than VS, glioma or pre-senile cataract), and unilateral VS at early age with an affected first-degree parent, sibling or child. Patients with NF-2 usually present between the ages of 18 and 24 years with tinnitus, hearing loss and balance difficulties. Symptoms of unilateral tinnitus, asymmetric hearing loss or unresolving vertigo or imbalance warrant a gadolinium-enhanced MRI with a neurotological consultation to rule out brainstem pathology.

NF-2 is caused by inactivation of the NF-2 tumor suppressor gene on chromosome 22 (22q12.2) which encodes the "Merlin" protein. Like a double negative, inactivation of a tumor suppressor gene produces an autosomal-dominant inheritance pattern identical to classical activating mutations.

When a diagnosis of NF-2 is entertained, evaluation should include a complete family history; a detailed head and neck and neurological examination with attention to cranial nerve deficits, and an MRI of the brain with dedicated images to detect bilateral VS, meningiomas and optic gliomas. Spinal MRI with gadolinium should be performed to look for spinal meningiomas or schwannomas, and ophthalmologic evaluation should be obtained in cases with visual loss or with suspicion of juvenile cataracts.

Unilateral VS and NF-2