Table 5 Patients with DSP and DM compared to those with DM and additional risk factors for neuropathy: electrodiagnostic studies.

Motor studies	n	DM as only cause for neuropathy (n = 48), mean (SD), range	n	DM and another potential cause for neuropathy (n = 55), mean (SD), range	p value
Median
Amplitude (nl: >4 mV)	15	7.4 (2.5), 4.1–11.8	21	6.2 (4.0), 0.7–17.7	0.24
Conduction velocity (nl: >49 m/s)	15	49 (6), 38–61	21	47 (10), 33–68	0.47
Ulnar
Amplitude (nl: >6 mV)	27	8.1 (2.1), 3.0–11.9	31	6.7 (3.0), 0.9–14.0	0.04
Conduction velocity (nl: >50 m/s)	27	52 (5), 37–62	31	49 (10), 32–68	0.17
Peroneal
Amplitude (nl: >2 mV)	38	2.6 (2.1), 0–9.6	43	2.0 (2.6), 0–9.3	0.05
Conduction velocity (nl: >40 m/s)	34	38 (7), 21–49	30	39 (8), 22–64	0.98
Tibial
Amplitude (nl: >4 mV)	44	4.5 (4.0), 0–15.3	50	4.1 (4.7), 0–19.2	0.23
Conduction velocity (nl: >40 m/s)	40	38 (6), 24–52	41	38 (6), 21–45	0.65
No. patients with conduction block		0/44		6/52	0.03
Distal leg denervation		13/42		26/50	0.06
Sensory nerve amplitude
Median (nl: >15 μV)	16	8.0 (8.0), 0–24	23	7.9 (9.6), 0–32	0.76
Ulnar (nl: >10 μV)	25	10.0 (8.9), 0–33	32	6.0 (7.1), 0–24	0.03
Radial (nl: >20 μV)	21	15. 0 (9.9), 0–38	31	10.2 (8.0), 0–35	0.06
Sural (nl: >6 μV)	44	4.0 (5.4), 0–27	50	2.5 (4.8), 0–23	0.04
Absent sural sensory potential		19/44		34/50	0.01*

DM, diabetes mellitus; nl, normal value; SD, standard deviation.

*Significant p value.