Sleep Disorder Specialist During The Day I Just Drop Off In A Sleep For 3-4 Minutes Then Wake Up. What Is This Called?

During the day I just drop off in a sleep for 3-4 minutes then wake up. What is this called? - sleep disorder specialist

I know there is a name for this sleep disorder, but can not remember. I will consult a specialist. about this? I am a pensioner of 50 years, having Parkinson's disease.