CD4 and Cognitive impairment: Univariate logistic regression showed that older age at onset (OR 1.030, 95% CI 1.085–1.143, P = 0.002) or at testing (OR 1.090, 95% CI 1.034–1.149, P = 0.001), education time less than 9 years (OR 5.318, 95% CI 1.859–15.215, P = 0.002), longer disease duration (OR 1.769, 95% CI 1.072–2.919, P = 0.026), and higher levels of total T lymphocyte (OR 0.530, 95% CI 0.318–0.882, P = 0.015), CD4+ T lymphocyte (OR 0.997, 95% CI 0.995–0.999, P = 0.024), and CD8+ T lymphocyte (OR 0.582, 95% CI 0.355–0.955, P = 0.032) were significant predictors of cognitive impairment of ALS patients (Tables 3 and 4).