Neurophysiological function
| . | Healthy control . | Diabetes with no neuropathy . | Diabetes with neuropathy . | ROC threshold . | Sensitivity . | Specificity . |
|---|---|---|---|---|---|---|
| Autonomic testing | ||||||
| Phase 2 Valsalva maneuver blood pressure (mmHg) | 1.80 ± 0.40 | 1.33 ± 0.71* | 0.73 ± 0.67*† | <2 | 89 | 57 |
| Valsalva ratio | 1.54 ± 0.23 | 1.50 ± 0.29 | 1.26 ± 0.21*† | <1.3 | 73 | 78 |
| Heart rate variability (bpm) | 16.3 ± 6.7 | 12.5 ± 5.9 | 8.2 ± 5.0*† | <9.6 | 73 | 74 |
| Valsalva phase 4 blood pressure overshoot | 1.92 ± 0.28 | 1.41 ± 0.75* | 0.86 ± 0.87*† | <2 | 70 | 67 |
| Fall in systolic blood pressure during tilt (mmHg) | 15.9 ± 13.9 | 14.9 ± 12.0 | 19.6 ± 16.4 | >16 | 52 | 53 |
| Change in heart rate during tilt (bpm) | 16.0 ± 8.5 | 14.6 ± 8.5 | 7.7 ± 13.7* | <12 | 35 | 39 |
| Nerve conduction studies | ||||||
| Peroneal amplitude (mV) | 6.7 ± 2.6 | 5.5 ± 2.6 | 3.5 ± 2.4*† | <4.5 | 73 | 78 |
| Sural amplitude (μV) | 10.7 ± 8.0 | 7.5 ± 6.5* | 3.4 ± 4.1*† | <4 | 68 | 70 |
| Peroneal velocity (m/s) | 47.7 ± 4.4 | 45.0 ± 4.9 | 42.0 ± 5.4*† | <44 | 64 | 72 |
| Peroneal distal latency (ms) | 4.7 ± 0.8 | 4.7 ± 0.6 | 5.0 ± 0.7*† | >4.5 | 61 | 53 |
| Sural velocity (m/s) | 47.4 ± 5.8 | 45.7 ± 6.3 | 42.6 ± 6.5*† | <43 | 59 | 70 |
| Sensory testing | ||||||
| Cold-pain foot (°C) | 6.4 ± 10.1 | 7.3 ± 9.3 | 2.1 ± 4.7*† | <10 | 89 | 29 |
| Heat-pain hand (°C) | 46.0 ± 4.5 | 45.5 ± 4.5 | 46.8 ± 3.2 | >45.1 | 80 | 41 |
| Cold detection foot (°C) | 25.7 ± 7.0 | 25.3 ± 6.4 | 17.2 ± 10.5*† | <25.5 | 77 | 70 |
| Monofilament threshold right (g) | 3.76 ± 0.4 | 3.8 ± 0.5 | 4.7 ± 1.3*† | >4.1 | 76 | 75 |
| Vibratory detection toe | 4.8 ± 7.4 | 5.2 ± 7.6 | 20.6 ± 26.0*† | >4.3 | 76 | 72 |
| Heat-pain foot (°C) | 47.4 ± 3.5 | 47.7 ± 2.5 | 49.0 ± 1.7*† | >48.3 | 69 | 62 |
| Heat detection hand (°C) | 34.3 ± 2.9 | 35.1 ± 1.9 | 36.7 ± 3.8*† | >34.5 | 69 | 49 |
| Heat detection foot (°C) | 39.1 ± 5.9 | 40.3 ± 4.2 | 44.4 ± 4.2*† | >43 | 67 | 72 |
| Vibratory detection thumb | 1.0 ± 0.5 | 2.0 ± 2.5* | 3.8 ± 6.3*† | >1.5 | 67 | 70 |
| Cold detection hand (°C) | 30.2 ± 2.0 | 31.1 ± 4.9 | 28.9 ± 3.7† | <30.2 | 61 | 72 |
| Cold-pain hand (°C) | 6.2 ± 6.5 | 7.7 ± 8.9 | 4.2 ± 6.9* | <3 | 61 | 54 |
| Cutaneous blood flow | ||||||
| Direct leg % change | 248 ± 285 | 202 ± 205 | 114 ± 159* | <125% | 77 | 60 |
| Direct forearm % change | 490 ± 435 | 372 ± 366 | 344 ± 314 | <315% | 55 | 50 |
| Axon reflex leg % change | 146 ± 212 | 150 ± 257 | 63 ± 74* | <75% | 69 | 49 |
| Axon reflex arm % change | 291 ± 354 | 412 ± 920 | 720 ± 3,370 | <220% | 71 | 43 |
| . | Healthy control . | Diabetes with no neuropathy . | Diabetes with neuropathy . | ROC threshold . | Sensitivity . | Specificity . |
|---|---|---|---|---|---|---|
| Autonomic testing | ||||||
| Phase 2 Valsalva maneuver blood pressure (mmHg) | 1.80 ± 0.40 | 1.33 ± 0.71* | 0.73 ± 0.67*† | <2 | 89 | 57 |
| Valsalva ratio | 1.54 ± 0.23 | 1.50 ± 0.29 | 1.26 ± 0.21*† | <1.3 | 73 | 78 |
| Heart rate variability (bpm) | 16.3 ± 6.7 | 12.5 ± 5.9 | 8.2 ± 5.0*† | <9.6 | 73 | 74 |
| Valsalva phase 4 blood pressure overshoot | 1.92 ± 0.28 | 1.41 ± 0.75* | 0.86 ± 0.87*† | <2 | 70 | 67 |
| Fall in systolic blood pressure during tilt (mmHg) | 15.9 ± 13.9 | 14.9 ± 12.0 | 19.6 ± 16.4 | >16 | 52 | 53 |
| Change in heart rate during tilt (bpm) | 16.0 ± 8.5 | 14.6 ± 8.5 | 7.7 ± 13.7* | <12 | 35 | 39 |
| Nerve conduction studies | ||||||
| Peroneal amplitude (mV) | 6.7 ± 2.6 | 5.5 ± 2.6 | 3.5 ± 2.4*† | <4.5 | 73 | 78 |
| Sural amplitude (μV) | 10.7 ± 8.0 | 7.5 ± 6.5* | 3.4 ± 4.1*† | <4 | 68 | 70 |
| Peroneal velocity (m/s) | 47.7 ± 4.4 | 45.0 ± 4.9 | 42.0 ± 5.4*† | <44 | 64 | 72 |
| Peroneal distal latency (ms) | 4.7 ± 0.8 | 4.7 ± 0.6 | 5.0 ± 0.7*† | >4.5 | 61 | 53 |
| Sural velocity (m/s) | 47.4 ± 5.8 | 45.7 ± 6.3 | 42.6 ± 6.5*† | <43 | 59 | 70 |
| Sensory testing | ||||||
| Cold-pain foot (°C) | 6.4 ± 10.1 | 7.3 ± 9.3 | 2.1 ± 4.7*† | <10 | 89 | 29 |
| Heat-pain hand (°C) | 46.0 ± 4.5 | 45.5 ± 4.5 | 46.8 ± 3.2 | >45.1 | 80 | 41 |
| Cold detection foot (°C) | 25.7 ± 7.0 | 25.3 ± 6.4 | 17.2 ± 10.5*† | <25.5 | 77 | 70 |
| Monofilament threshold right (g) | 3.76 ± 0.4 | 3.8 ± 0.5 | 4.7 ± 1.3*† | >4.1 | 76 | 75 |
| Vibratory detection toe | 4.8 ± 7.4 | 5.2 ± 7.6 | 20.6 ± 26.0*† | >4.3 | 76 | 72 |
| Heat-pain foot (°C) | 47.4 ± 3.5 | 47.7 ± 2.5 | 49.0 ± 1.7*† | >48.3 | 69 | 62 |
| Heat detection hand (°C) | 34.3 ± 2.9 | 35.1 ± 1.9 | 36.7 ± 3.8*† | >34.5 | 69 | 49 |
| Heat detection foot (°C) | 39.1 ± 5.9 | 40.3 ± 4.2 | 44.4 ± 4.2*† | >43 | 67 | 72 |
| Vibratory detection thumb | 1.0 ± 0.5 | 2.0 ± 2.5* | 3.8 ± 6.3*† | >1.5 | 67 | 70 |
| Cold detection hand (°C) | 30.2 ± 2.0 | 31.1 ± 4.9 | 28.9 ± 3.7† | <30.2 | 61 | 72 |
| Cold-pain hand (°C) | 6.2 ± 6.5 | 7.7 ± 8.9 | 4.2 ± 6.9* | <3 | 61 | 54 |
| Cutaneous blood flow | ||||||
| Direct leg % change | 248 ± 285 | 202 ± 205 | 114 ± 159* | <125% | 77 | 60 |
| Direct forearm % change | 490 ± 435 | 372 ± 366 | 344 ± 314 | <315% | 55 | 50 |
| Axon reflex leg % change | 146 ± 212 | 150 ± 257 | 63 ± 74* | <75% | 69 | 49 |
| Axon reflex arm % change | 291 ± 354 | 412 ± 920 | 720 ± 3,370 | <220% | 71 | 43 |
Data are means ± SD or % for sensitivity and specificity. Characteristics of the study groups were compared by one-way ANOVA with Tamhane T2 post hoc tests. ROC curves were generated with the selected maximal sensitivity and specificity for each test shown, and test values for the selection are reported as the ROC threshold.
*P < 0.01 vs. healthy control subjects;
†P < 0.01 vs. diabetes without neuropathy.