The sole issue in this case is whether the trial court erred in limiting the testimony of a board-certified neuropsychologist regarding brain damage allegedly suffered by the plaintiff, Mary K. Sanchez, in an automobile accident. We find the trial court was correct in its ruling.
Sanchez sued Frank N. Derby and Blanche Conrad, defendants, for injuries Sanchez allegedly sustained as a result of a rear end automobile collision on Interstate 680 in Omaha on April 21, 1982. Following trial, the jury awarded Sanchez $4,808.20, to be paid by both defendants. We affirm.
At trial, Sanchez called Charles J. Golden, Ph.D., a board-certified neuropsychologist, as an expert witness. Sanchez had been referred to Dr. Golden by her attorney and by Dr. Harold Ladwig, her neurologist. Dr. Golden, a licensed psychologist, first evaluated Sanchez in November 1984. He interviewed and tested Sanchez. Dr. Golden reviewed plaintiff’s medical records, which included history of care and treatment at Bergan Mercy Hospital, Immanuel Medical Center, and Omaha Neurological Clinic, as well as records from Sanchez’ mental health counselor, a psychiatrist, and her obstetrician-gynecologist. Dr. Golden determined that Sanchez was suffering from a chronic pain syndrome. That means she had a pain problem for more than 6 months which had not responded to medical treatment and that it “was not going away.”
In ruling upon an objection, the trial judge held that Dr. Golden would only be permitted to testify that the pain plaintiff was experiencing was tied to soft-tissue injuries received in the accident.
Plaintiff claims that Dr. Golden should have been permitted to testify to his opinion as it is contained in the following offer of proof:
[T]he client [Sanchez] presents a clinical picture of a somewhat histrionic individual whose premorbid status was that of an individual with marginal coping skills and resources. Since the accident of April 1982 there has been *499a significant decline in level of function as well as an exacerbation of her histrionic tendencies. The most probable causes [sic] of this behavioral change is either (1) a combination of a post traumatic stress disorder and a reaction to chronic pain in a previously marginal personality or (2) an organic affective disorder secondary to mild subcortical brain injury (around the orbital frontal areas) which can occur in accidents such as this.
While it is possible at this time to state firmly that one of these causes is indeed the most probable cause of her problems as the problems clearly date from the time of the accident as well as follow the pattern expected in such disorders, it is not possible to choose between them at present. The type of mild subcortical brain dysfunction which could cause this type of injury cannot [by] itself be easily identified by objective tests which are currently clinically available. Although the pattern of the disorder (especially the denial, the inability to recognize the nature of her problems, and the somewhat primitive thought patterns associated with her analysis of emotion) is consistent with such a diagnosis, it can also represent in this woman an intensification because of a post traumatic stress disorder related to the accident itself and the chronic physical pain which ensued from the accident.
(Emphasis supplied.)
Contrary to plaintiff’s contention, the narrow question on appeal is not whether Dr. Golden is qualified as an expert regarding brain damage, but whether the trial judge abused his discretion in excluding the testimony of Dr. Golden on the particular issue in question.
Dispositive of that question is whether Dr. Golden’s excluded testimony would supply specialized knowledge which would aid the jury in understanding the evidence or in determining a fact in issue. Neb. Rev. Stat. § 27-702 (Reissue 1985).
The admission or exclusion of expert testimony is largely within the broad discretion of the trial court. To obtain reversal on the grounds of the exclusion of evidence, an abuse of discretion must be shown. See, Lincoln East Bancshares v. Rierden, 225 Neb. 440, 406 N.W.2d 337 (1987); Bay v. House, *500226 Neb. 521, 412 N.W.2d 466 (1987); Johannes v. McNeil Real Estate Fund VIII, 225 Neb. 283, 404 N.W.2d 424 (1987); Aetna Cas. & Surety Co. v. Nielsen, 222 Neb. 92, 382 N.W.2d 328 (1986); State v. Schenck, 222 Neb. 523, 384 N.W.2d 642 (1986).
Here, the trial judge found that to allow Dr. Golden’s opinion testimony with respect to the cause of Sanchez’ behavioral change would be to invite a jury to speculate on the testimony of an expert. The expert must possess facts which enable him to express a reasonably accurate conclusion as distinguished from a mere guess or conjecture. State v. Johnson, 215 Neb. 391, 338 N.W.2d 769 (1983). Dr. Golden’s opinion as stated in the offer of proof is couched in alternatives, one of which is no more than a “possibility” and does not meet the certainty required. See, Hare v. Watts Trucking Service, 220 Neb. 403, 370 N.W.2d 143 (1985); Scott v. State, 218 Neb. 195, 352 N.W.2d 890 (1984); Lane v. State Farm Mut. Automobile Ins. Co., 209 Neb. 396, 308 N.W.2d 503 (1981).
The trial judge did not abuse his discretion in excluding Dr. Golden’s opinion as set forth in the offer of proof. The verdict and judgment of the trial court should be affirmed.
Affirmed.