What causes constant jerking while asleep?

Constant jerking while asleep can be due to multiple sleep disorders. It would be essential to define the problem in more detail. It would be helpful to know if the problem begins shortly after falling asleep or later in the night. This helps to determine which stage of sleep the movements occur. If they are nightly then a sleep study would be helpful. A home video could be helpful as well. If the hitting and kicking occur during REM (dream) sleep this may be classified as REM Behavior Disorder. This condition may be related to medication or alcohol effect or even neurological disorders which have not even manifested themselves. You need to get your husband to a sleep specialist, preferably a neurologist who is also board certified in sleep medicine. Other sleep disorders such as Periodic Limb Movement Disorder should be considered but this disorder is not usually associated with being hit although it is a possibility.

Your husband may have restless leg disorder, sleep apnea, or other sleep disorders. He will need to best observed and tested in a sleep laboratory.