This article reports the clinical features and prognosis of a patient with anti-N-methyl-D-aspartate receptor（NMDAR）encephalitis comorbid with novel coronavirus infection. After anti-NMDAR encephalitis is comorbid with SARS-CoV-2 infection，the symptoms may worsen，and timely immunoadsorption and second-line immunotherapy can help with disease recovery.

Objective To observe the clinical efficacy of simple knee trainer on active knee flexion in patients with hemiplegia after stroke.Methods From March, 2020 to May, 2021, 46 hemiplegics after stroke in Beijing Bo'ai Hospital were randomly divided into control group (n = 23) and experimental group (n = 23). Both groups accepted routine rehabilitation training, and the experimental group accepted knee flexion exercise training in sitting position through the simple knee trainer, for eight weeks. They were measured active knee flexion angle in sitting position and maximum flexion angle in walking before and after training, as well as Holden Functional Ambulation Category (FAC).Results Both active knee flexion angle in sitting position and maximum flexion angle in walking significantly increased in both groups after training (|t| > 6.991, P < 0.001), and increased more in the experimental group than in the control group (t > 2.185, P < 0.05). The grade of FAC also improved in both groups (|Z| > 2.828, P < 0.01), and no significant difference was found between groups (Z = -0.821, P = 0.412).Conclusion The application of simple knee trainer can effectively improve the active range of motion of knee, which may be used in clinic- and community-based rehabilitation.