Adrenaline increases the "alertness" of the nervous system, meaning it's ready to trigger muscle contraction. It also increases the amount of blood flow and changes the tension of the muscles, which, ...

Infectious agents can cause muscle twitching and spasms, too. The most commonly known is probably tetanus, which causes a phenomenon called lockjaw, where the neck and jaw muscles contract to the ...

While sitting still at your desk or watching TV, you sense a feeling of muscular discomfort in your arm or leg. It’s not quite a charley horse, but you can see your skin pulsating involuntarily, as if ...

There’s nothing quite as distracting as a sudden eye flutter while you’re trying to work, it’s the universal sign that you’re probably stressed out, burnt out, or just haven’t seen a pillow in far too ...

Functional tics are dramatic, involuntary movements or sounds usually made in response to a trigger. While similar to other tic disorders, they have different causes and treatment options. Functional ...

Tic disorders are conditions featuring sudden, non-rhythmic movements or vocalizations. A formal tic disorder diagnosis is determined by tic frequency, duration, and type. Tics are non-rhythmic ...