Table 2.
Comparison of neurophysiological tests, and corneal nerve fiber pathology between control subjects and type 2 diabetic patients with or without stratified diabetic neuropathy
| Control subjects | Stage of diabetic neuropathy | ||||
|---|---|---|---|---|---|
| Stage I | Stage II | Stage III | Stage IV+V | ||
| MCV of median nerve (m/s) | 57.1 ± 0.5 | 56.8 ± 0.5 | 53.6 ± 0.5***### | 50.3 ± 0.5&&& | 46.1 ± 0.8$$$ |
| Amplitude of median nerve (mV) | 6.3 ± 0.52 | 5.0 ± 0.44 | 3.4 ± 0.33# | 2.9 ± 0.33## | 2.7 ± 0.36## |
| SCV of ulnar nerve (m/s) | 63.7 ± 0.6 | 62.6 ± 0.5 | 60.3 ± 0.6*** | 57.7 ± 0.5&& | 53.4 ± 1.0$$$ |
| Amplitude of ulnar nerve (μV) | 26.9 ± 1.7 | 20.9 ± 2.0 | 17.1 ± 1.4*** | 15.7 ± 1.6 | 8.0 ± 0.7&&,$ |
| CPT 2000 Hz | 209 ± 8.1 | 237 ± 12.1 | 271 ± 8.7* | 324 ± 19.3& | 407 ± 31.1$$ |
| CPT 250 Hz | 84.6 ± 3.8 | 95.7 ± 6.1 | 110.4 ± 4.3 | 134.3 ± 15.2* | 196.9 ± 26.1$$ |
| CPT 5 Hz | 48.6 ± 2.4 | 52.9 ± 4.0 | 57.0 ± 2.8 | 77.9 ± 11.8* | 110.2 ± 20.0&&& |
| CVR-R (%) | 3.84 ± 0.31 | 3.50 ± 0.20 | 3.69 ± 0.20 | 2.97 ± 0.19* | 2.18 ± 0.26&&& |
| Corneal nerve fiber density (/mm2) | 31.7 ± 0.9 | 24.1 ± 0.7*** | 22.9 ± 0.6*** | 21.5 ± 0.9*** | 20.5 ± 0.9***,# |
| Corneal nerve fiber length (mm/mm2) | 12.2 ± 0.3 | 9.6 ± 0.3*** | 9.5 ± 0.3*** | 8.4 ± 0.4*** | 7.7 ± 0.4***,# |
| Corneal nerve branch density (/mm2) | 12.3 ± 0.8 | 9.9 ± 0.5* | 9.3 ± 0.5*** | 9.1 ± 0.6*** | 7.2 ± 0.5***,# |
| Corneal nerve branch length (mm/mm2) | 2.51 ± 0.14 | 2.08 ± 0.09 | 2.06 ± 0.09* | 2.04 ± 0.15* | 1.57 ± 0.12& |
| Tortuosity grade | 1.98 ± 0.04 | 2.53 ± 0.06*** | 2.52 ± 0.05*** | 2.41 ± 0.07*** | 2.49 ± 0.05*** |
| Beading frequency | 23.8 ± 0.23 | 21.9 ± 0.31*** | 21.4 ± 0.24*** | 21.7 ± 0.28*** | 21.4 ± 0.39*** |
Data are mean ± standard error of the mean in control subjects and type 2 diabetic patients subdivided by stratified diabetic neuropathy.
P < 0.05
P < 0.001 compared with control subjects
P < 0.05
P < 0.01
P < 0.001 compared with patients with stage I neuropathy
P < 0.05
P < 0.01
P < 0.001 compared with patients with stage II neuropathy
P < 0.05
P < 0.01
P < 0.001 compared with patients with stage III neuropathy. Statistical analysis was carried out with analysis of valiance. CPT, current perception threshold; CV, coefficient of variation; MCV, motor nerve conduction velocity; NF, nerve fascicle; SCV, sensory nerve conduction velocity.