
135 Mich. App. 645 (1984)
354 N.W.2d 294
DENGLER
v.
STATE FARM MUTUAL INSURANCE COMPANY
Docket No. 70375.
Michigan Court of Appeals.
Decided May 18, 1984.
Alan L. Kaufman, for plaintiff.
William D. Eggenberger, for defendant.
Before: J.H. GILLIS, P.J., and T.M. BURNS and N.J. KAUFMAN,[*] JJ.
PER CURIAM.
Plaintiff appeals as of right from a directed verdict granted in favor of defendant after a jury trial.
On February 5, 1978, Ralph Dengler was involved in an automobile accident which, according to the police report, caused considerable damage to his vehicle but no injuries to him. One year later, Mr. Dengler visited his family physician complaining of headaches, which he blamed on the automobile accident the year before. The family physician was unable to relieve Mr. Dengler's headaches and referred him to a neurologist. The neurologist concluded that the headaches were unrelated to the accident and recommended that a CAT scan be performed. However, before the CAT scan could be performed, Ralph Dengler suffered a subarachnoid hemorrhage, as a result of which he is totally disabled.
Ralph Dengler's wife, Scarlett, acting individually and as guardian of Ralph Dengler, brought this action against defendant as insurer of their *648 automobile under a standard no-fault automobile policy which provided that defendant would pay all reasonable medical expenses related to any injuries sustained as a result of operation of the automobile.
In reviewing the granting of a motion for directed verdict, this Court must determine, viewing the evidence in the light most favorable to the plaintiff, whether reasonable persons could honestly reach different conclusions as to whether the plaintiff had established a prima facie case. Ransford v Detroit Edison Co, 124 Mich App 537, 542; 335 NW2d 211 (1983).
Plaintiff's theory was that the automobile accident of February 5, 1978, had caused Ralph Dengler to suffer from hydrocephalus, which in turn caused or contributed to the subarachnoid hemorrhage which disabled Mr. Dengler. However, there was no evidence in the record supporting the crucial links in this chain, those being that the accident caused hydrocephalus, that Mr. Dengler had hydrocephalus, or that the hydrocephalus existed prior to the subarachnoid hemorrhage. One of plaintiff's experts declined to express an opinion as to any causal relationship between the automobile accident and the subarachnoid hemorrhage. The other expert admitted that his testimony on this point would be pure speculation, and even with that qualification testified that there was only a "remote possibility" that the hydrocephalus preexisted the hemorrhage. This expert opined that there was a "much better possibility" that Mr. Dengler's subarachnoid hemorrhage was caused by work-related pressures than by hydrocephalus. The proofs, even taken in a light most favorable to the plaintiff, would not enable reasonable minds to conclude that Mr. Dengler had become hydrocephalic *649 as a result of the automobile accident and that the hydrocephalic condition had caused the subarachnoid hemorrhage which resulted in his present disabilities. Plaintiff's failure to establish this vital causal relationship was fatal to her prima facie case.
Plaintiff's complaint that the trial court, in deciding the motion for a directed verdict, improperly considered the testimony elicited during defense counsel's cross-examination of the plaintiff's witnesses is without foundation. The fact that the evidence must be viewed in a light most favorable to the plaintiff does not mean that damaging evidence must be ignored. The trial court properly granted the defendant's motion for directed verdict.
Plaintiff also objects to the trial court's decision to exclude the testimony of Dr. Charles Beauchamp, whom the trial court found to be qualified as an expert in internal medicine but not neurology. Plaintiff attempted to qualify the doctor as an expert in differential diagnosis, which is simply a method by which all possible causes of a condition are listed and then the various causes are ruled out so as to leave the most likely cause or causes of a particular patient's problem. However, even if Dr. Beauchamp were able to testify as to the three most likely causes of a subarachnoid hemorrhage, it still would have required an expert in neurology to take the next step and rule out all but hydrocephalus. By his own admission, Dr. Beauchamp was unqualified to testify as an expert witness in this area. The decision to allow or exclude the introduction of expert opinion evidence is left to the trial court's discretion and will not be reversed on appeal absent an abuse of discretion. Slocum v Ford Motor Co, 111 Mich App 127; 314 NW2d 546 *650 (1981), lv den 414 Mich 886 (1982). We find no abuse of discretion.
In her final argument, plaintiff contends that defendant's refusal to pay duplicating benefits forced Mr. Dengler to go to the veteran's hospital for treatment and that, therefore, plaintiff is entitled to receive from defendant the difference between the cost of the services Mr. Dengler received at the veteran's hospital and the cost of those services had Mr. Dengler received those services in a private hospital. This argument is wholly without merit.
Contrary to plaintiff's assertion, defendant refused to stipulate that the insurance policy in question provided for duplicating benefits. Moreover, the set-off provision of the no-fault act would preclude plaintiff's recovery of these costs even if the policy did provide for duplicating benefits. That provision states:
"Benefits provided or required to be provided under the laws of any state or the federal government shall be subtracted from the personal protection insurance benefits otherwise payable for the injury." MCL 500.3109(1); MSA 24.13109(1).
This Court already ruled in Bagley v State Farm Mutual Automobile Ins Co, 101 Mich App 733; 300 NW2d 322 (1980), that this set-off provision applies to medical benefits received from the Veteran's Administration. Plaintiff has failed to distinguish her case from Bagley, supra, and the reasoning in Bagley is consistent with the Legislature's intent to reduce or contain the cost of basic insurance. O'Donnell v State Farm Mutual Automobile Ins Co, 404 Mich 524, 544; 273 NW2d 829 (1979), app dis 444 US 803 (1979). Thus, the trial court correctly *651 excluded evidence which would have established what Mr. Dengler's treatment would have cost in a private hospital.
Affirmed.
NOTES
[*]  Former Court of Appeals Judge, sitting on the Court of Appeals by assignment.
