MKSAP Quiz: Recent worsening of balance in Parkinson disease
A 76-year-old man is evaluated for recent worsening of balance. He has no dizziness or lightheadedness. The patient has an 8-year history of Parkinson disease treated with carbidopa-levodopa and entacapone. Findings from physical, cognitive, cerebellar, and sensory examinations are unremarkable. Which of the following is the most appropriate test to determine the patient's risk of falling backward?
A 76-year-old man is evaluated for recent worsening of balance. He has no dizziness or lightheadedness. The patient has an 8-year history of Parkinson disease treated with carbidopa-levodopa and entacapone.
On physical examination, vital signs are normal; no orthostatic decrease in blood pressure is noted. The patient has masked facies, a resting tremor, and bradykinesia. Gait assessment reveals mild shuffling without freezing. Findings from cognitive, cerebellar, and sensory examinations are unremarkable.
Which of the following is the most appropriate test to determine the patient's risk of falling backward?
A. Head impulse test
B. Pull test
C. Romberg test
D. Tandem gait test
MKSAP Answer and Critique
The correct answer is B. Pull test. This content is available to MKSAP 18 subscribers as Question 63 in the Neurology section. More information about MKSAP is available online.
This patient's risk of falling backward is best determined by the pull test, which is the most sensitive predictor of risk of backward falls in Parkinson disease. During this test of postural stability, the examiner throws the patient off base by pulling backward on the shoulders; the test is considered positive if the patient topples into the examiner's arms or takes more than two corrective steps. Backward falls are often related to loss of postural reflexes and resultant postural instability. Additional factors, including insufficient control of motor symptoms, dyskinesia, and orthostatic hypotension, also can contribute to falls in Parkinson disease. In this patient, history and gait assessment did not reveal any interference with balance caused by freezing of gait or lower body dyskinesia, and he had no symptoms or findings suggestive of orthostatic hypotension.
The head impulse (or thrust) test involves asking the patient to keep eyes focused on a distant object; the examiner then suddenly turns the head approximately 20 degrees. Patients with a normal vestibuloocular reflex remain focused on the object. An abnormal response, indicating a peripheral vestibular lesion, is movement of the eyes off the target followed by jerking of the eyes back to the target (corrective saccade). In this patient, the absence of vertigo and dizziness makes a vestibular cause less likely and testing unnecessary. The Dix-Hallpike test is another bedside test for assessment of peripheral vestibular pathology and is most helpful in the presence of vertigo, which is absent here.
A positive Romberg test, defined as severe unsteadiness elicited by eye closure in a patient standing comfortably, indicates impairment of large sensory pathways at the spinal-cord or peripheral nerve level. The absence of abnormal findings on sensory and reflex examinations makes a sensory ataxia less likely in this patient.
Tandem gait, in which a patient walks on a straight line, may be intact in the early phase of Parkinson disease. An impaired tandem gait, however, can indicate cerebellar or sensory ataxia or other causes of imbalance but is not a sensitive or specific predictor of backward falls.
Key Point
- The pull test is the most sensitive predictor of the risk of backward falls in Parkinson disease.