Table 4.

Review of retrospective studies.

First author (year)	Country	Sample size	Sex (M:F)	Average age	Duration of disease (average)	Diagnosed by	Outcomes
Jeon et al. (1997) [38]	Korea	17	12:5	52.4	No mention	Diagnostic criteria by Jokelainen et al.	Analyzing the age of onset, clinical signs, ALS type, treatment methods, outcomes, etc.
Li et al. (2017) [39]	China	288	169:119	No mention	No mention	El Escorial criteria	Analyzing the clinical characteristics, survival rate, and TCM syndrome in patients with ALS

M, male; F, female; ALS, amyotrophic lateral sclerosis; and TCM, traditional Chinese medicine.