This is an article that appeared recently in the Parkinson Report: Unusual Symptoms in Parkinson's Disease By Lisa M. Shulman, MD, Clinical Research Fellow William J. Weiner, MD, Director, Movement Disorders Center, University of Miami School of Medicine A National Parkinson Foundation Center of Excellence PARKINSON REPORT, National Parkinson Foundation Inc., Vol. XV, Issue II, 2nd Quarter, 1994. Do you ever feel a tremor inside your body that cannot be seen by others? Forty-four (44) percent of patients with Parkinson's disease said "yes" in a recent study conducted at the U. of Miami School of Medicine, Department of Neurology, Movement Disorders Center. This "internal tremor" is experienced in either the extremities, chest or abdomen. Commonly, it is reported on the same side as the other parkinsonian symptoms, such as the typical observable tremor. Internal tremor generally occurs in brief episodes lasting less than half an hour and with a frequency of several times per week. Eighty (80) percent of patients describe this as unpleasant, uncomfortable or painful. The sensation of internal tremor is the most recent example of a number of sensory symptoms that have gained increasing recognition in Parkinson's disease. A variety of sensory phenomena such as aching, burning, tingling and numbness have been previously studied. Approximately 40% of patients report these sensations. Similar to our findings in internal tremor, these other sensory symptoms occur intermittently and often correspond in location to the side of the body more affected by Parkinson's disease. Internal tremor and other sensory symptoms of Parkinson's disease are not simply a curiosity; they are a significant source of difficulty and disability for many patients. Sensory symptoms may appear early in the course of illness, perhaps prior to the motor symptoms. Both patients and physicians are less familiar with the sensory manifestations of Parkinson's disease, impeding accurate and early diagnosis. Sensory symptoms are often not mentioned in descriptions of parkinsonism. This may be a source of bewilderment and concern to both patients and family members. Additionally, both internal tremor and other Parkinson's related sensations may be uncomfortable and of sufficient intensity to merit specific treatment. While sensory symptoms may be of special, or even predominant concern to the patient, they pose a unique dilemma to the physician. The doctor must rely totally on the historical accuracy and insights of the patient. Unlike the assessment of motor symptoms, such as the observable resting tremor, rigidity, slowing of movement or difficulty walking, sensory symptoms cannot be observed or objectively evaluated by the physician. Identification and management will be optimized by precise reporting of the timing, frequency, location and severity of symptoms. Information regarding factors associated with both the exacerbation and relief of unusual sensation can also be helpful. Interestingly, when patients with and without internal tremor are compared, there is no difference in the duration or severity of their Parkinson's disease symptoms. There also is no observable tremor alone. The patients with internal tremor are far more likely to experience other sensory symptoms (aching, tingling, burning, numbness) than their counterparts without internal tremor. What is the cause of internal tremor? The answer to this question remains unclear, but we can speculate that it may represent a very mild tremor that is too subtle to be detected by observation. If this is true, it is indeed surprising that there was no discrepancy in the presence or severity of resting tremor. More than 80 percent of patients with Parkinson's disease have an observable resting tremor. Alternatively, the sensation of internal tremor may have more in common with the other Parkinson's related sensory symptoms. The parts of the brain that are affected by the changes of Parkinson's disease may play a role in the interpretation of sensory information. Misinformation in the form of unusual sensory phenomena may be the result. In certain patients readjustment of the medications used in the treatment of their motor symptoms can relieve the sensory symptoms as well. Although it is important for both patients and physicians to be aware of the existence of Parkinson's related sensory symptoms, one must be wary of developing an overly casual attitude to reports of unusual sensations. When symptoms suggest other possible causes, appropriate evaluation should be pursued to exclude these alternatives. The potential causes of recurring sensory symptoms are numerous, and need to be approached on an individual basis. While our knowledge of these symptoms remains incomplete, awareness of the widespread nature of this problem can be reassuring. Further studies of the sensation of internal tremor are currently planned at the U. of Miami to aid in both better understanding and treatment of this previously undescribed symptom in Parkinson's disease. END Regards, Alan