Neurotron, Incorporated

   Innovative Medical Technology

                 Established 1981

Normative Neuroselective Current Perception Threshold (CPT) Values

The standardized computerized automated sNCT/CPT evaluation methodology removes tester and testing method factors from effecting CPT measures obtained from different populations at different locations and time periods. In contrast, these factors represent major confounding variables for sensory nerve conduction velocity studies¹. Numerous studies from the past 28 years have evaluated CPT measures from healthy individuals from various populations and the following table summarizes findings from a representative example of these studies. The most commonly tested sites are the fingers and the toes.

Healthy Mean CPT Values (SD) , 1 CPT = 10 microAmperes

Face

(Trigeminal n)

Finger

(Median n)

Toe

(Peroneal n)

CPT

Frequency

USA

n=338

Korea

n=400

USA

n=334

Japan

n=1632

Taiwan

n=50

USA

n=310

Taiwan

n=50

5 Hz

10(10)

11(8)

46(27)

61(30)

50(25)

73(34)

74(30)

250 Hz

19(14)

21(12)

81(42)

93(44)

78(30)

125(52)

126(50)

2000 Hz

118(52)

99(28)

226(80)

236(62)

230(70)

322(110)

325(106)

The above measures were obtained using the double-blind forced choice testing procedure with a resolution of +/- 20 µAmp, p<0.006.  each body site has a characteristic CPT value.

The references for the above cited data are:

Japan - Takekuma, K., Ando, F., Niino, N., Shimokata, H. Age and gender differences in skin sensory threshold assessed by current perception in community-dwelling Japanese, Journal of Epidemiology, Volume10(1):S33-S38, 2000.

Korea - Kim, H., Kho, H., Kim, Y., Lee, with., Chung, with. Reliability and Characteristics of Current Perception Thresholds. Journal of Orofacial Pain Volume 14(4): 286-292, 2000.

Taiwan - 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, Volume 22: 1531-1537, 1999.

USA - Neuval^® Database II - Normative Data, Neurotron, Inc. Baltimore, MD, USA, 2001.  This normative data was obtained primarily from the following institutions: Johns Hopkins Medical Institution, University of Maryland School of Pharmacology, Creighton University School of Medicine, New York Medical College, New York University Medical Center, Palmer College of Chiropractic and the University of New Mexico School of Medicine.

This graph depicts average healthy CPT measures. On the horizontal axis are the three stimulation frequencies and on the vertical axis are the CPT measures in mAmperes. Two significant characteristics of healthy CPTs may be easily observed in this graph. The first, is the significant increase in sensory thresholds, within each site tested, as the frequency of the stimulus is changed from 5 Hz to 250 Hz to 2000 Hz. The second, is the consistent relationship between CPT measures recorded from different body sites but evoked with the same frequency stimulus. Cephalic measures represented by the trigeminal testing (the lowest line) have lower or more sensitive values than the median nerve on the finger (the middle line) and values from the peroneal nerve on the toe have the highest values. The CPT data analyses will detect a ratio abnormality when these healthy characteristic relationships are absent.

rev 01/07/10