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. 2022 Jan 7;16(2):295–320. doi: 10.1177/19322968211035375

Table 5.

Quantitative Sudomotor Axon Reflex Testing (QSART).

Author(s) & Study Aim Study Population & Design Study Outcomes
Kamel et al. 122
-Assess the clinical utility of CSP, QSART, SSR & AFT in detection of SFN related to glycemic dysregulation
N = 52
n = 26 +SFN
n = 9 T1D, n = 9 T2D
n = 8 IGT
M = 50.8 ± 2.6 yrs/age
n = 26 Controls
M = 48.9 ± 2.6 age/yrs
Cross-sectional
• QSART (Q-Sweat System; WR Medical Electronics, Stillwater, MN, USA),) results showed a sensitivity of 58% & specificity of 100%
• Sensitivity of the Q-Sweat System may have been improved by limiting the sample to T1D & T2D participants & more rigorous evaluation of sensitivity
• Q-Sweat System revealed an optimal specificty (100%) although suboptimal sensitivity (58%)
Krieger et al. 123
-Evaluate performance of Sudoscan against QSART (Q-Sweat System) in diagnosing DPN
N = 63
n = 27 T2D, +DPN
M = 69 ± 4.8 yrs/age
n = 20 T2D, -DPN
M = 66 ± 5.8 yrs/age
n = 16 MCs
M = 64 ± 5.1 yrs/age
Cross-sectional
• Q-Sweat System could not differentiate between the 3 groups (+DPN, -DPN, MCs)
• Q-Sweat System showed poor discriminatory performance
Loavenbruck et al. 124
-Report a method that quantifies axon reflex sweating from individual SGs with nanoliter precision
N = 72
n = 20 +Neuropathy
(n = 11 +DM)
Aged 45–82 yrs
n = 52 AACs
Aged 21–88 yrs
Cross-sectional
• Comparing +neuropathy to AAC groups, AUC of 0.90 achieved for directly & indirectly stimulated rate/SG & total sweat at the calf
• AUC of 0.80 & 0.84, respectively, achieved for directly stimulated rate/SG & total sweat at the feet
• AUC of 0.58 & 0.74, respectively, achieved for indirectly stimulated rate/SG & total sweat at the feet
• Overall, SST shows impressive performance for quantifying axon reflex sweating from individual SGs with nanoliter precision

Abbreviations: AAC, age-adjusted control; AFT, autonomic function testing; AUC, area under the curve; AUROC, area under receiver operator characteristic; CSP, cutaneous silent periods; DM, diabetes mellitus; DPN, diabetic polyneuropathy; IGT, impaired glucose tolerance; M, mean; MCs, matched controls; QSART, quantitative sudomotor axon reflex testing; SFN, small fiber neuropathy; SG, sweat gland; SST, sensitive sweat test; T1D, type 1 diabetes; T2D, type 2 diabetes; yrs, years.