Diagnostic Criteria for Diabetic Sensorimotor Polyneuropathy (DSPN)

The Diabetic Sensorimotor Polyneuropathy (DSPN) is a symmetrical, length-dependent sensorimotor polyneuropathy attributable to metabolic and microvessel alterations as a result of chronic hyperglycemia exposure (diabetes) and cardiovascular risk covariates. 

Definitions of minimal criteria for DSPN
1. Possible Clinical DSPNSymptoms or signs of DSPN. Symptoms may include: decreased sensation, positive neuropathic sensory symptoms (e.g. ‘asleep numbness’, ‘prickling’ or ‘stabbing’, ‘burning’ or ‘aching’ pain) predominantly in the toes, feet, or legs. Signs may include: symmetric decrease of distal sensation or unequivocally decreased or absent ankle reflexes.

2. Probable Clinical DSPNA combination of symptoms and signs of distal sensorimotor polyneuropathy with any two or more of the following: neuropathic symptoms, decreased distal sensation, or unequivocally decreased or absent ankle reflexes.

3. Confirmed Clinical DSPNAn abnormal nerve conduction study and a symptom or symptoms or a sign or signs of sensorimotor polyneuropathy. Severity of DSPN can be assessed by staged or continuous approaches described above and by dysfunction and disability scores.

4. Subclinical DSPNNo signs or symptoms of polyneuropathy. Abnormal nerve conduction, as described above, is present.


Dyck's Stages of Severity for DSPN
An alternative approach to estimating severity is to indicate severity by grades:

• Grade 0 = no abnormality of NC, e.g., sum 5 nerve conduction (NC) normal deviates <95th percentile or another suitable NC criterion
• Grade 1a = abnormality of NC, e.g., sum 5 NC normal deviates >/=95th percentile without symptoms or signs
• Grade 1b = NC abnormality of stage 1a plus neurologic signs typical of DSPN but without neuropathy symptoms
• Grade 2a = NC abnormality of stage 1a with or without signs (but if present, <2b) and with typical neuropathic symptoms
• Grade 2b = NC abnormality of stage 1a, a moderate degree of weakness (i.e., 50%) of ankle dorsiflexion with or without neuropathy symptoms.

References:

1. Dyck PJ, Albers JW, Andersen H, Arezzo JC, Biessels GJ, Bril V, Feldman EL, Litchy WJ, O'Brien PC, Russell JW; on behalf of the Toronto Expert Panel on Diabetic Neuropathy. Diabetic Polyneuropathies: Update on Research Definition, Diagnostic Criteria and Estimation of Severity. Diabetes Metab Res Rev. 2011; 27: 620–628. [Medline]
2. Tesfaye S, Boulton AJ, Dyck PJ, Freeman R, Horowitz M, Kempler P, Lauria G, Malik RA, Spallone V, Vinik A, Bernardi L, Valensi P; Toronto Diabetic Neuropathy Expert Group. Diabetic neuropathies: update on definitions, diagnostic criteria, estimation of severity, and treatments. Diabetes Care. 2010 Oct;33(10):2285-93. [Medline]
3. Dyck PJ. Detection, characterization, and staging of polyneuropathy: assessed in diabetics. Muscle Nerve. 1988 Jan;11(1):21-32. [Medline]