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Sensitivity, Specificity, Fiber Diameter Specificity of Neurometer® CPT Measures

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Sensitivity and specificity are critical measures in determining the utility of any diagnostic procedure. For sNCT/CPT studies, sensitivity refers the procedure’s ability to detect the presence of sensory abnormalities in a group of patients. If the patients being tested are at high risk for neuropathy, such as patients with advanced diabetes, then the sensitivity would be expected to be high. Testing a group of randomly selected diabetic children, however, would naturally include some that have not yet developed neuropathy and yield a correspondingly lower level of detection sensitivity.  This is illustrated in the three studies in the table below.  A test that is “too” sensitive can result in false positive measures that wrongly identify a healthy patient as having an abnormality. Specificity is the statistic that expresses the ability of a diagnostic procedure to correctly identify healthy (control) subjects. A specificity of 100% means that there were no false positive measures in the healthy group. Diagnostic tests balance sensitivity against specificity, so that the maximum number of abnormalities are detected with the fewest number of false positives.


      Sensitivity/Specificity of sNCT CPT Measures, Diabetic Polyeuropathy



Study (endnote #)




  n= 33 randomly selected adult diabetic patients, 54 controls (1)  



  n= 73 randomly selected adult diabetic patients, 47 controls (2)  



  n= 92 randomly selected diabetic children, 80 controls (3)  


Diabetic polyneuropathy may affect small and/or large diameter sensory nerve fibers.  In contrast, there are various neuropathological conditions are highly neuroselective for the specific sub-populations of nerve fibers.  There are characteristic selective predominantly small and/or large fiber neuropathies.  The Neurometer sNCT CPT evaluation is unique in its ability to selectively evaluate the large and small fibers within a test site test and provide a test specificity for the type of fiber impairment.  The sensory nerve conduction velocity evaluation is selective for large fibers only and was insensitive to the small fiber pathology in the studies cited below.  Note, in the fifth study below the neuroselectivity of vibration neuropathy (with genetic confirmation) by the sNCT evaluation may also be demonstrated in laboratory rats.  The other studies in the table below are human.


         Small and Large Sensory Nerve Fiber Pathology Specificity of sNCT CPT Measures


100 % Small Fiber Specificity


   Study (#)


Fabry's Disease

 n= 15 patients, 50 controls (4)


Arsenic Exposure  n= 85 exposed, 75 controls (5)  
Syringomyelia Myelopathy  n= 10 patients, 10 controls (11)  

100 % Large Fiber Specificity

Vibration Neuropathy  n= 20 controls, 59 hand-arm vibration (6)  
Vibration Neuropathy n= 364 hand-arm vibration (7)  
Vibration Neuropathy Rat Study n= 16 tail vibration, 20 controls (8)  
Organo-phosphate Pesticide Exposure  n= 19 controls n= 60 exposed (9)  
Radiculopathy  n= 48 patients, 11 controls (10)  


Follow this link for additional information regarding the neuroselectivity of the Neurometer sNCT CPT evaluation and these links for additional sNCT CPT neuroselectivity related publication bibliographies: neuroscience, neuroselective neuropathies, pharmaceutical neuroselectivity, and the neuroselectivity of ischemia.



(1)  Katims, J.J., Naviasky, E., Ng, L.K.Y., Bleecker, M.L., Rendell, M. New Screening Device for Assessment of Peripheral Neuropathy. J Occupational Med, Vol 28(12):1219-1221, 1986.

(2)  Umezawa, S., Kanamori, A., Yajima, Y., Aoki, C. Current Perception Threshold in evaluating diabetic neuropathy. Diabetes (Japan) Volume 8(1):711-719, 1997.

(3) Barkai, L., Kempler, P., Vámosi, I., Lukács, K., Marton, A., Keresztes, K. Peripheral Sensory Nerve Dysfunction in Children and Adolescents with Type 1 Diabetes Mellitus. Diabetic Medicine, Volume 15:228-233, 1998.

(4)  Ro, L.S., Chen, S.T., Tang, L.M., Hsu, W.C., Chang, H.S., Huang, C.C. Current Perception Threshold Testing in Fabry’s Disease. Muscle & Nerve, Vol. 22: 1531-1537, 1999.

(5) Tseng, C.H. Abnormal current perception thresholds measured by neurometer among residents in blackfoot disease-hyperendemic villages in Taiwan, Toxicology Letters, Vol. 146(1):27-36, 2003.

(6)  Kurozawa, Y., Nasu, Y. Current Perception Thresholds in Vibration-Induced Neuropathy. Archives of Environmental Health, Vol. 56(3):254-256, 2001.

(7)  Pelmear, P.L. and Kusiak, R. Clinical Assessment of Hand-Arm Vibration Syndrome. Nagoya Journal of Medical Science, Volume 57:27-41, 1994.

(8)  Krajnak, K., Waugh, S., Wirth, O., Kashon, M.L. Acute vibration reduces Abeta nerve fiber sensitivity and alters gene expression in the ventral tail nerves of rats. Muscle & Nerve ,Vol. 36(2):197-205, 2007.
(9)  Husin, L.S., Uttaman, A., Hisham, H.J., Hussain, I.H.S. The Effect of Pesticide on the Activity of Serum Cholinesterase and Current Perception Threshold on the Paddy Farmers in Muda Agricultural Development Area, MADA, Kedah, Malaysia, Medical Journal of Malaysia, Volume 54(3):320-324, 1999.

(10)  Yamashita, T., Kanaya, K., Sekine, M., Takebayashi, T., Kawaguchi, S., Katahira, G. A quantitative analysis of sensory function in lumbar radiculopathy using current perception threshold testing. Spine, Volume 27(14):1567-70;2002

(11)  Cui, L., Zhu, P., Fu, H., Starr, A. Current Perception Threshold (CPT) in Syringomyelia. Journal of Chinese Neurology, Vol. 36(6):447-44, 2003.

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