What is a TVT?
The timed vibration test or TVT is a simple but powerful method of gauging neurological function. In particular, vibration testing assesses the large myelinated A-alpha and A-beta sensory fibers. TVTs have been done in research settings and to a limited extent in clinics for decades. In the past, this exam was performed with a traditional tuning fork and a handheld timer. The clinician would hit the tuning fork and then apply it to the patient’s anatomy while simultaneously starting the timer (alternatively the clinician would count). The patient would then indicate when the vibrations subsided beyond perception. Obvious draw backs included variability in tuning fork vibration (different clinicians applying different forces, multiple manufacturers making the tuning forks) and difficulty in accurately timing when the patient lost perception of the vibration. This lack of standardization and difficulty in performing the test limited its clinical use.
The advent of the ETF128 has given new life to this valuable test. Now TVTs can be performed in a quick, standardized fashion at the point-of-care. Those testing the feet of diabetic patients will find the Hallux TVT Scale of the front of the device particularly helpful for assessing diabetic peripheral neuropathy (DPN). The times generated by successive TVTs can also be used to track the patient’s status over time. This not only alerts the clinician to the progression of any neurological deficits, it can be used as an educational tool to better inform patients.