Central post-stroke pain: predictors and relationship with magnetic resonance imaging and somatosensory evoked potentials

Table 3 SSEP; of median and tibial nerves

Variables	Patients with CPSP (n = 23)	Patients without CPSP (n = 42)	t test	p value
Median N9
Mean ± SD	11.0 ± 1.6	9.9 ± 1.1	3.3	0.002**
Range	8–14	8–12	3.3	0.002**
Median N20
Mean ± SD	22.4 ± 2.8	20.1 ± 1.1	4.7	< 0.0001**
Range	18–26	19–23	4.7	< 0.0001**
Median N9–N20 IPL
Mean ± SD	11.5 ± 1.6	10.2 ± 0.93	4.2	0.0001**
Range	9–14	8–12	4.2	0.0001**
Tibial N21
Mean ± SD	22.8 ± 2.0	20.5 ± 0.99	7.1	< 0.0001**
Range	20.3–26.7	18–22	7.1	< 0.0001**
Tibial P40
Mean ± SD	44.4 ± 3.3	40.8 ± 1.1	4.5	< 0.0001**
Range	41.1–51.4	40–51	4.5	< 0.0001**
Tibial N21–P40 IPL
Mean ± SD	21.6 ± 1.9	20.3 ± 0.11	4.4	< 0.0001**
Range	17.4–25.5	19–21	4.4	< 0.0001**

**Significant p value at < 0.01, CPSP central post-stroke pain, SSEP somatosensory evoked potential, SD standard deviation, t Student’s (paired) t test