Patients with cervical spine damage especially if they suffer from breathing issues can benefit from a sleep study. A polysomnography is carried out by a sleep lab and can show many body functions while the patient is sleeping.
The measurements include EEG, ECG, breathing frequence, blood oxygen, muscle tension, leg movement, eye movement and body position.
A sleep study can show disorders like central sleep apnea which can be related to damage of the brain and medulla oblongata.
More information about sleep apnea you can find here.