Aging populations are stretching existing healthcare systems to their limits in both developing and developed countries. Telemedicine is a promising solution to this challenging problem. Under the conventional data compression paradigm, long-time recording of electroencephalography (EEG) signals still generates excessive amount of data, which requires large data storage and long transmission time. While promoting mobile telemedicine with compressed sensing (CS) as a key system for EEG monitoring, this paper investigates the effect of epoch length on CS to compress EEG signals. Experimental results show that a longer epoch length leads to better signal compression at the expense of larger signal reconstruction time. At a sampling frequency of 256 Hz, a 4-s epoch length is suitable when using a general desktop computer to perform signal reconstruction.