The exact requirements for diagnostic investigations will vary from case to case, but a complete physical examination will be required.
As stress appears to be an important factor a detailed history will be taken regarding the household circumstances. Referral to behaviour specialists may also be required.
If there are indications of other neurologic abnormalities, then CSF samples, CT scans and MRI investigations may be appropriate to rule out other causes.
A thorough dental investigation is always appropriate. This will always require general anaesthesia and blood samples for metabolic and haematologic profiles are commonly obtained. Viral screens may also be obtained. Once anaesthetised the first consideration is to rule out any possible oral or pharyngeal foreign body. Then the whole mouth requires assessment and appropriate treatment for any resorptive lesions, fractured teeth or periodontal disease. Complete intraoral radiographic surveys must be utilised. If further extractions are required then these should be performed in an expert manner - as traumatic extractions may themselves exacerbate symptoms.
If there is a surplus of blood after the profiles have been performed, then (with your permission if a case is confrimed as being positive for FOPS) a sample might be sent to a National Genetic Laboratory to help with future research.