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Neuropad as a diagnostic tool for diabetic autonomic and sensorimotor neuropathy
Author(s) -
Spallone V.,
Morganti R.,
Siampli M.,
Fedele T.,
D’Amato C.,
Cacciotti L.,
Maiello M. R.
Publication year - 2009
Publication title -
diabetic medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.474
H-Index - 145
eISSN - 1464-5491
pISSN - 0742-3071
DOI - 10.1111/j.1464-5491.2009.02760.x
Subject(s) - medicine , sudomotor , receiver operating characteristic , valsalva maneuver , diagnostic accuracy , diabetic neuropathy , polyneuropathy , diabetes mellitus , area under the curve , peripheral neuropathy , cardiology , audiology , endocrinology , blood pressure
Aims The aim of the present study was to determine the diagnostic accuracy of the Neuropad sudomotor test for diabetic cardiovascular autonomic neuropathy (CAN) and diabetic polyneuropathy (DPN), the latter assessed using a multi‐level diagnostic approach. Methods In 51 diabetic patients, CAN, symptoms and signs of DPN, vibration perception threshold (VPT), cold (CTT) and warm thermal perception thresholds (WTT) were measured. Neuropad response was determined as normal (complete colour change) or abnormal (absent or incomplete colour change). The time until the complete colour change (CCC time) was recorded. Results CCC time showed significant correlations with all the neurological parameters, the strongest of which were with Valsalva ratio (ρ = −0.64, P < 0.0001), symptoms of DPN (ρ = 0.66, P < 0.0001), postural hypotension (ρ = 0.54, P = 0.0001) and CTT (ρ = −0.54, P = 0.0001). CCC time showed moderate diagnostic accuracy for both CAN and DPN: the areas under the receiver operating characteristic (ROC) curves were 0.71 and 0.76, respectively. The diagnostic characteristics of three cut‐off values of CCC time, identified by ROC analysis (i.e. 10, 15 and 18 min), were analysed. Compared with 10 min, the 15‐min cut‐off value provided better specificity (from 27% to 52% and from 31% to 62% for CAN and DPN, respectively) and a better likelihood ratio for negative result (from 0.67 to 0.34 and from 0.58 to 0.33) without lowering sensitivity (from 82% to 82% and from 85% to 80%). Conclusions Neuropad is a reliable diagnostic tool for both CAN and DPN, albeit of only moderate accuracy. Extending the observation period to 15 min provides greater diagnostic usefulness.