In Service Chevrolet v. Atwood, 61 Ark. App. 190, 966 S.W.2d 909 (1998), the Court quoted Paulsen v. State, 249 Neb. 112, 541 N.W.2d 636 (1996), with approval as we explained further: "Our cases discussing the sufficiency of expert opinions have been a survey of various characterizations by the claimant's experts as to how certain they are that the claimant's injury was caused by his or her employment. We have held that expert medical testimony based on "could," "may," or "possibly" lacks the definiteness required to meet the claimant's burden to prove causation. Our well-known preference for the use of the phrases "reasonable degree of medical certainty" or "reasonable degree of probability" is an indication to courts and parties of the necessity that the medical expert opinion must be stated in terms that the trier of fact is not required to guess at the cause of the injury." (61 Ark. App. at 196-97, 966 S.W.2d at 913.)