In 1960, Florence Semmes and Sidney Weinstein developed a set of nylon monofilaments to measure sensory loss in their patients. The Semmes-Weinstein Monofilament Test has since become the standard for initial screening of diabetes patients to determine if they have a loss of protective sensation associated with peripheral neuropathy.
The American Diabetes Association states that all patients with diabetes should be screened for peripheral neuropathy associated loss of protective sensation in their feet when they are first diagnosed and at least annually thereafter.
A study recently reported in the Annals of Internal Medicine has shed more light on who, in addition to diabetics, are candidates for undergoing a monofilament test. While the monofilament test has primarily been used to assess for sensory loss in diabetic individuals, the study, titled, “Peripheral Neuropathy Associated with Increased Mortality Risk, Irrespective of Diabetes Status “, showed that an individual with peripheral neuropathy has an increased mortality risk, regardless of their diabetes status. In the study, peripheral neuropathy was assessed using a 10-gram standard monofilament test.
Click HERE to download a Diabetic Neuropathy Monofilament Foot Screen form (guidelines and documentation)
The prospective cohort study used data from the National Health and Nutrition Examination Survey on 7,116 adults ages 40 years or older who had standardized monofilament testing for peripheral neuropathy. It found an overall prevalence of neuropathy of 13.5%, 27.0% in those with diabetes and 11.6% in those without diabetes. During a median of 13 years of follow-up, 2,128 participants died, 488 of cardiovascular causes.
Mortality was increased with peripheral neuropathy: 57.6 per 1,000 person-years with both diabetes and peripheral neuropathy, 34.3 per 1,000 person-years with peripheral neuropathy but no diabetes, 27.1 per 1,000 person-years with diabetes but no peripheral neuropathy, and 13.0 per 1,000 person-years with neither condition.
“Patients with both diabetes and peripheral neuropathy had the highest risk of death during the study’s 13-year follow-up, but the next highest rate was in patients with peripheral neuropathy but no diabetes, followed by those with diabetes without peripheral neuropathy.”
What are Other Conditions That Can Lead to Peripheral Neuropathy?
Considering that the presence of peripheral neuropathy in the non-diabetic individual places them at increased mortality risk, what other segments of the population who are not diabetic, should consider receiving a monofilament test to determine if they have peripheral neuropathy and a loss of protective sensation?
Other causes of peripheral neuropathy include:
- Obesity and impaired glucose tolerance
- Some cancer chemo treatments
- Certain medications
- Inflammatory infections (HIV and AIDS, Lyme disease, Epstein-Barr virus
- Exposure to certain toxins like mercury, lead, or arsenic
- Auto-immune diseases (lupus, rheumatoid arthritis,
- Poor nutrition (vitamin B12 deficiency & an excess of vitamin B6)
- Kidney and liver disorders
- Certain genetic conditions that can lead to peripheral neuropathy
- Other idiopathic (cause unknown) causes
Included in the published article was the authors’ statement that, “Our study contributes to the growing body of literature supporting the concept that PN [peripheral neuropathy] is associated with substantial clinical sequelae”, adding that the findings show that “the prevalence of PN among adults without diabetes is substantial and that PN may be an underrecognized risk factor for death.”
These findings raise the question as to if additional guidelines will be developed for peripheral neuropathy monofilament testing by identifying segments of the population with specific health conditions (see “Other causes of peripheral neuropathy include” above) besides diabetes that should undergo regular testing for peripheral neuropathy and a loss of protective sensation. In the meantime, if you are an older adult and have impaired glucose tolerance, are obese, or have one or more of these other health conditions, you may want to talk to your doctor about having a peripheral neuropathy screen test. Talking to your doctor may be especially important if you have symptoms such as tingling, numbness, pain, or a crawling like sensation in your skin on the bottom of your feet, or a lack of sensation to light pressure.
Hicks, Caitlin W, et al, Peripheral Neuropathy and All-Cause and Cardiovascular Mortality in U.S. Adults. Annals of Internal Medicine, Vol. 174, No. 2, February 2021.
Lynn Perkes is a full-time faculty member at Brigham Young University-Idaho teaching courses in Kinesiology and Biomechanics, Applied Kinesiology and Assessment, Therapeutic Exercise, and Physical Therapist Assistant classes. He writes part-time for ProhealthcareProducts.com, which sells healthcare, therapy, fitness, and personal protective equipment products.