From the Guidelines
Bradykinesia is clinically tested through several specific physical examination techniques, including observing spontaneous movements, finger tapping tests, rapid alternating movements, and foot tapping, to assess for key features such as slowness, progressive reduction in speed and amplitude, hesitations, and decreased movement amplitude, as described in the most recent study 1. To test for bradykinesia clinically, the following steps can be taken:
- Observe the patient's spontaneous movements, noting their facial expressions, arm swing while walking, and overall movement speed.
- Perform finger tapping tests, asking the patient to tap their index finger against their thumb as quickly and with as much amplitude as possible for 10-15 seconds on each hand.
- Have them perform rapid alternating movements like pronation-supination of the hands or opening and closing the fist repeatedly.
- Test for foot tapping by having the patient tap their foot on the floor. During these tests, assess for several key features, including:
- Slowness in initiating movement
- Progressive reduction in speed and amplitude during repetitive tasks
- Hesitations or freezing during movement sequences
- Overall decreased movement amplitude The examiner should note if movements become smaller, slower, or irregular over time, which is characteristic of bradykinesia, as noted in studies 1. These tests are particularly important in evaluating for Parkinson's disease and other parkinsonian syndromes, as bradykinesia is a cardinal feature of these conditions and reflects dysfunction in the basal ganglia motor circuits, as discussed in the study 1.
From the Research
Clinical Assessment of Bradykinesia
To test for bradykinesia clinically, several methods and tools can be employed, including:
- The Unified Parkinson's Disease Rating Scale (UPDRS) and its revised version, the Movement Disorder Society revision of the UPDRS (MDS-UPDRS) 2
- Technology-based assessments such as gyrosensors, Coordination Ability Test System, Brain Test, quantitative digitography, Motus motion analysis system, precision real-time image-based motion analysis, and the At-Home Testing Device 2
- Computer vision technology to analyze videos of finger-tapping tasks 3
- Timed performance tests like the Purdue Pegboard test and the Bradykinesia-Akinesia Incoordination (BRAIN) test 4
- Motion capture analysis of finger tapping, which can provide measures such as average frequency, maximum opening velocity, and amplitude decrement 4
Reliability and Validity of Assessment Tools
The reliability and validity of these assessment tools have been examined in various studies:
- The UPDRS and MDS-UPDRS have been shown to be reliable and applicable scales for assessing bradykinesia in Parkinson's disease and atypical parkinsonian syndromes 2
- The bradykinesia subscale of the UPDRS has been found to be a valid and reliable assessment when administered separately from the rest of the UPDRS motor examination 5
- Computer vision technology has been validated as a tool for analyzing bradykinesia in outpatient clinic videos of people with Parkinson's disease, with high accuracy in distinguishing between disease states and correlating with clinical ratings 3
- Motion capture analysis of finger tapping has been found to be a powerful discriminator between Parkinson's disease patients and controls, with measures such as amplitude decrement and maximum opening velocity being particularly useful 4
Pathophysiological Mechanisms
The pathophysiological mechanisms underlying bradykinesia are complex and involve network dysfunction, including the basal ganglia, primary motor cortex, and cerebellum, as well as abnormal sensorimotor processing 6