Although the International Federation of Diabetes (IDF) put out these clinical practice guidelines in 2017, we were gratified to see our 2014 ETF Proof-of-Concept study cited on page 19 of the document. We are cited in the section on using a 128 Hz tuning fork to assess diabetic peripheral neuropathy.
We are excited to report the results of recently published research article utilizing the ETF. This study by Raymond et al. from the Journal of Diabetes Science and Technology has recommended the ETF as the best choice of vibration testing instruments to pair with Semmes-Weinstein monofilament testing when performing lower extremity sensation testing in diabetic patients. This study protocol compared the ETF to the traditional 128 Hz tuning fork and biothesiometer in terms of ease of use, testing time and standardization of vibration output. The authors recommended the ETF over the other devices. We welcome the results of this study and look forward to more research papers validating the clinical use of the ETF.
The ETF was originally conceived as a way of assisting providers and patients in the prevention of diabetic foot complications through improved diagnosis and tracking of diabetic peripheral neuropathy (DPN). With this is mind, the company is pleased to announce our latest product updates. Customer feedback combined with the latest evidenced-based research has resulted in three product improvements.
The vibration output has been adjusted to make the testing time two seconds shorter to diagnose early neuropathy. The old scale cut-off point was at nine seconds, the new one is set at seven seconds.
The vibration output in the 128 Hz Mode at three seconds approximates the vibration level of the typical biothesiometer at the 25 volt level. This is the standard cut-off indicating increased risk of diabetic foot ulceration. Constant Mode is also set to the this level for those who prefer the On/Off Method of testing.
The new labeling on the front of the device (see below) now reflects a risk-based stratification scale that is more clinically relevant. The 25 volt biothesiometer level is denoted at the three second mark on this scale.
These changes will help improve the interpretation of test results and reduce testing time for providers.
A new study by Geiss from Diabetes Carereveals a disturbing trend toward increasing rates of lower extremity amputations in young (18-44 y/o) and middle-aged (45-64 y/o) diabetic patients. This comes after a two-decade long decline in amputation rates in all diabetic patients. The study noted this upward spike in data collected from 2010-2015 in the US. As to the potential causes for this finding, the authors suggest a “fundamental failure” in amputation prevention. They go on to note:
“Many amputations may be avoided through attention to self- and clinical care practices to manage risk factors, including glycemic control and cardiovascular disease risk factors, and through early detection and appropriate treatment of foot ulcers . Increasing rates of NLEAs (non-traumatic lower extremity amputations), particularly minor amputations, suggest either early prevention practices (e.g., self management education, appropriate footwear, foot exams, and identification of high-risk feet) might not be optimally performed to prevent foot ulcers and/or there may be delays in timely treatment of ulcers.”
Indeed, this systemic failure to prevent these tragic events is a recurring frustration well known to those treating diabetic patients. An aggressive team-based approach incorporating primary care, podiatry, diabetes educators, vascular surgeons, nutritionists and wound care specialists is required in addition to active and willing patient participation. Additionally, the importance of aggressive early prevention cannot be over emphasized. This is germane in the diabetic foot with regard to early detection of diabetic neuropathy. The graphic below illustrates the concept well. In essence, the earlier neuropathy is diagnosed, the earlier prevention can be implemented to avoid amputations. A worthy goal for patients and providers alike.
Earlier diagnosis of neuropathy indicated by the yellow arrow could help avoid amputations through earlier preventative intervention.
In contrast, current guidelines focus on identifying Loss of Protective Sensation (LOPS) as a trigger for prevention.
Although more closely associated with carpal tunnel syndrome, hypothyroidism is a recognized cause of peripheral neuropathy. While the mechanism of neuropathy in untreated hypothyroidism is unclear, researchers have theorized that it may be attributed to the deposition of mucopolysaccharides or to the accumulation of soft tissue edema in proximity to peripheral nerves. Regardless of the precise mechanism, it is hypothesized that these underlying metabolic derangements cause nerve entrapments resulting in the demyelinating polyneuropathy described in the literature. Symptoms including tingling, numbness and paresthesia are most often reported in the hands and feet of afflicted patients.
Clinical Case I
A 62 y/o male with untreated hypothyroidism* of a 8-10 year duration presented complaining of progressively worsening paresthesia and numbness in the forefoot bilaterally of a one year duration. Patient history was negative for degenerative disc disease, diabetes or alcoholism.
Labs: Comprehensive Metabolic Panel, Vitamin B12, Folate, ESR, Lyme disease antibody and Free T4 were negative. TSH was elevated.
Neurological Testing: Office-based screening revealed reduced sharp sensation in the left foot, normal 10gm monofilament testing and reduced vibratory sensation as documented by a timed vibration test with the ETF (TVT 7.4s right hallux, 8.4s left hallux).
*The patient notes being placed on thyroid hormone replacement therapy after his initial diagnosis. He admits to going against medical advice and discontinuing it after several months.
Clinical Case II
A 54 y/o male with undiagnosed hypothyroidism presented with progressive numbness in the toes over past 1-2 years. Patient history was negative for degenerative disc disease, diabetes or alcoholism.
Labs: Random blood glucose, Vitamin B12, Folate, Lyme disease antibody were negative. TSH was elevated and Free T4 was below normal.
Neurological testing: Office-based screening revealed reduced sharp sensation at the hallux bilaterally, normal 10gm monofilament test and reduced vibratory sensation as documented by a timed vibration test with the ETF (TVT 7.5s right 5th metatarsal head, 7.6s left 5th metatarsal head).
NCV/EMG testing confirmed peripheral neuropathy consistent with a demyelinating process in the feet bilaterally.
Although an uncommon cause of peripheral neuropathy, undiagnosed or untreated hypothyroidism should be suspected in cases where more obvious etiologies are ruled out. Fortunately, patient symptoms often resolve with appropriate thyroid hormone replacement therapy over a 6-12 month period if treated promptly.