Syncope neurological syncope true Neurological causes of syncope include Chiari malformation, hyperekplexia (startle disease) and paroxysmal extreme pain disorder. With a Chiari malformation, coughing and straining on the toilet may trigger a transient loss of consciousness similar to a syncope. The exact mechanism is uncertain but increased downward herniation of the brain may compress the vertebro-basilar arteries and cranial nerves IX and X. A history of chronic headache and sensory symptoms associated with the collapse should lead to consideration of neuroimaging as decompression surgery can be curative.