Wiktionary
sleepy sickness
n. encephalitis lethargica; acute inflammation of the brain which causes drowsiness and mental disease.
WordNet
sleepy sickness
n. an encephalitis that was epidemic between 1915 and 1926; symptoms include paralysis of the extrinsic eye muscle and extreme muscular weakness [syn: sleeping sickness, epidemic encephalitis, lethargic encephalitis, encephalitis lethargica]