Coastal Neurological Medical Group, Inc.
9850 Genesee Avenue Suite 860La Jolla, California 92037Phone 858-453-3842 Fax 858-535-9390
Dee E. Silver, M.D.
Education to Knowledge for your benefit
REM BEHAVIOR DISORDER (RBD) IN PARKINSON'S DISEASE (IPD) AND OTHER SYNUCLEINOPATHIE'S
Rapid Eye Movement Sleep Behavior Disorder(RBD) occurs in patients with Parkinson's disease (PD), Multiple System Atrophy (MSA), Lewy Body Disease or also called Dementia With Lewy Bodies, (LBD or DLB) and other synucleinopathie's which are characterized by alpha synuclein developing through a aggregation process being present in the cells in an abnormal state to oligomers to Lewy Bodies. There are some movement disorder specialists who believe that these different but similar clinical states may best be divided from other diseases that have phosphorylated tau as a predominate protein found on autopsy. These tau pathological diseases would be Progressive Supranuclear Palsy (PSP) and Cortical Basal Syndrome (CBS) and the Frontal Temporal Dementia Syndromes (FTDS). This grouping may be of benefit clinically because of the clinical features that differ in the later clinical picture.
At the present time, to accurately diagnose clinically, you need an autopsy and even then there may be mixed pathology. Some autopsies may have taupathy,alpha synucleinopathy, beta amyloid pathologyand often even significant White Matter Disease (Leuroaresis) (WMD).
RBD occurs during sleep, REM sleep, when a person normally cannot move (is atonic). In RBD a patient with an alpha synucleinopathy will act out their dreams. They will talk out loud, scream, and thrash out with their arms and legs, fall out of bed or get out of bed and harm themselves or others. This is often repetitive but has a great deal of variability in frequency and severity. In my experience, RBD can occur rarely in other diseases such as Alzheimer’s disease but obviously we do not have the pathology in all these cases. It has been recognized by many that RBD anticipates diseases such as IPD, LBD and MSA. Now we have studies that support this anticipation and have used the DATScan as a test to support the diagnosis of patients that have substantia nigra cell loss. The DATScan shows reduced uptake of the isotope that measures the dopamine transporter at the presynaptic end terminal of the dopamine cells in the put amen and caudate. ThisDATScan isotope test seems to have about90% sensitivity and specificity, which states there is a chance of 10% false positives and 10% false negatives.
Multiple follow-up studies on RBD has shown that after 10 years from onset of the RBD 50% of the patients with the diagnosis will develop IPD and less likely MSA or DLB's. By 15 years 90% will have developed one of these 3 Neurodegenerative diseases (ND). Hence, this is a very significant predictor of one of these 3 diseases. Rather than thinking of this as being a terrible predictor, it will allow the patient to behave in a way which may reduce or delay the ND disease. Since we do not have a drug yet for neuro protection and stem cells are not a cure and yet to be shown of benefit, the patient can get in an exercise program which may delay ND diseases and aggressively treat any co morbidity such as hypertension, diabetes, and the metabolic syndrome. Since WMD may be related to these 3 and WMD is a major comorbidity in pathological studies of ND diseases, an exercise program, diet and medication may well be of benefit.
Dee E. Silver, M.D.August 14, 2017