Table 7.

Top 20 keywords for publications on PHN.

Rank	Frequency	Keyword	Centrality
1	2503	Postherpetic neuralgia	0.02
2	1132	Neuropathic pain	0.09
3	1015	Herpes zoster	0.02
4	960	Double blind	0.7
5	457	Efficacy	0.25
6	410	Pain	0.17
7	398	Management	0
8	335	Quality of life	0.07
9	279	Gabapentin	0.4
10	279	Diabetic neuropathy	0.21
11	274	Epidemiology	0.29
12	234	Placebo controlled trial	0.68
13	221	Risk factors	0.2
14	203	Randomized controlled trial	0.86
15	200	Diabetic peripheral neuropathy	0.64
16	182	Chronic pain	0
17	163	Trigeminal neuralgia	0.13
18	157	Impact	0.11
19	152	Therapy	0.31
20	147	Safety	0.17

PHN = postherpetic neuralgia