A new article written by Prabhakar et al. has demonstrated the utility of timed vibration testing in diagnosing distal sensory polyneuropathy (DSP) due to a variety of conditions. They utilized a 128 Hz tuning fork and a handheld stopwatch to time how long patients could feel the vibrations at the hallux, medial malleolus and tibial tuberosity. They noted sensitivity of 85% for the test. Additionally, they were able to conclude that patients with vibration sense lasting >8 seconds at the hallux were free of DSP. Coincidentally, this correlates well with the new 7 second cutoff for early neuropathy on theupdated ETF.
In our research into emerging uses for tuning forks, we came across an interesting study by Kothari et al. In their article, they hypothesized that improved timing of post-operative analgesics could be achieved by assessing the return of vibration perception. Specifically, they studied 60 male patients who had undergone inguinal herniorrhaphy under subarachnoid block. Patients were evenly divided into control and experimental groups. The experimental group was given medication upon return of vibration sense, controls were given their doses after complaining of pain. All patients had vibration testing performed at the anterior superior iliac spine (ASIS) reasoning that this large nerve fiber function would precede the recovery of small nerve fibers responsible for pain sensation. They suggested that optimal timing of analgesic administration could be achieved by monitoring the return of vibration perception thereby reducing patient pain and the need for additional pain medication.
The results of this study were promising as Kothari noted in their discussion: “…we conclude that if analgesic is given with the return of vibration sense as compared to actual return of subjective pain at the surgical site, then not only patient compliance is better (low VAS Score) but the respiratory and haemodynamic parameters also remain stable.”
Although this technique has not yet gained widespread popularity, it could develop into a helpful method of improving pain relief following surgery in the future.
The company was gratified to learn that the American Diabetes Association’s new Standards of Medical Care in Diabetes recommendations for 2017 have advised screening of all diabetic patients for large fiber neuropathy with a 128Hz tuning fork. Furthermore, the recommendations cited testing both small and large fiber nerves. This welcome clarification better reflects our current understanding of diabetic peripheral neuropathy. Clinicians are advised that small nerve fiber screening may be done with temperature or pinprick testing. The standing recommendations for 10 gm monofilament testing and annual foot exams remains unchanged.
The importance of these recommendations is underscored by a recent report in JAMA indicating that healthcare spending on diabetes topped a list of the 155 most common disease conditions in the U.S.. Previous research has demonstrated that spending on diabetic foot complications alone may be as high as 33% of the economic burden of diabetes on the U.S. healthcare system. Both these findings support the strategic implementation of aggressive prevention including diabetic foot exams.