Adverb
with spasms
in spurts and fits
Source: WordNetthe mouth was slightly open, and jerked violently and spasmodically at one corner Source: Internet
I began to write intermittently and spasmodically Source: Internet
In general, it will be found, that the eyelids close with a vibratory motion, or become spasmodically closed. Source: Internet
The myometrium contracts spasmodically in order to push the menstrual fluid through the cervix and out of the vagina. Source: Internet