Spinal accessory neuropathy in patients with chronic neck pain

Table 1 Electrophysiological results of the study groups (mean ± SD)

	Cases (n = 30)	Control (n = 10)	P value
Latency in millisecond (ms)
Left	2.98 ± 0.61	2.33 ± 0.36	0.0061
Right	2.96 ± 0.69	2.44 ± 0.38	0.028
Amplitude in millivolt (mv)
Left	3.29 ± 0.39	3.32 ± 0.42	0.9241
Right	3.36 ± 0.39	3.38 ± 0.48	0.8991

¹Mann-Whitney U test.

Table 2 Characteristics of subjects studied and neck disability index score

Characteristics	Number of patients	Score of NDI3	P value
Work task
Stressful	22	34.7 ± 9.5	0.011
Non-stressful	8	24.5 ± 3.1
Handedness
Right	28	32.2 ± 9.7	0.766
Left	2	34.1 ± 8.7
Sex
Male	13	37.5 ± 9.8	0.007
Female	17	28.4 ± 7.4
Pain site
Right	6	27.3 ± 9.1	0.1971
Left	6	30.1 ± 6.8
Both	18	34.8 ± 9.8
Age (yr)
< 40	18	28.2 ± 6.8	0.0092
≥ 40	12	38.1 ± 9.8
Disease duration (yr)
< 3	11	30.1 ± 8.4	0.377
≥ 3	19	33.4 ± 10.1

¹Analysis of variance test;

²Mann-Whitney U test;

³mean ± SD. Statistically significant at P < 0.05, comparison of patients in the study group. NDI: Neck disability index.