Patients with vertigo when lying down to sleep consider the following causes: 1. If there are transient episodes to be considered as caused by benign paroxysmal positional vertigo, also known as otolithiasis, which is caused by the irritation of the semicircular canal, caused by the irritation of the semicircular canal during the change of the specific position of the head by the dislodged otolith. The patient’s dizziness will be accompanied by brief visual rotation, and characteristic nystagmus can be seen.2. Vertigo when lying down to sleep is considered to be probably related to cervical spondylosis. When the patient’s cervical spine has problems such as disc herniation and spinal stenosis, if the patient lies down and sleeps in the wrong position, it may cause the patient’s cerebral vertebral artery to be compressed and cause insufficient blood supply to the brain, which may manifest as hair-activated vertigo symptoms.