W.J.C. appeals an order involuntarily committing him for treatment, sec. 51.20, Stats. A psychiatrist and a psychologist testified by telephone at the commitment hearing. Because W.J.C.’s due process rights were not violated by allowing the examining physicians to testify by telephone, we affirm the order.
W.J.C. was represented by counsel at the jury trial. W.J.C.’s parents and the two doctors testified. His parents testified in person concerning his behavior. Over W.J.C.’s objection, the doctors testified by telephone, under oath. Each doctor had filed a report with the court detailing his opinion of W.J.C.’s mental condition. The six-person jury found W.J.C. to be mentally ill, dangerous to himself or others, and a proper subject for treatment.
Because W.J.C. has been released from his six-month commitment, the case is moot. Generally, a case is moot when the decision sought by the parties cannot have any practical legal effect upon a then existing controversy. State ex rel. Watts v. Combined Community Ser*240vices Board, 122 Wis. 2d 65, 362 N.W.2d 104 (1985). Although the case is moot, we address the issue of telephone testimony. It will likely arise again yet evade review because the appellate process cannot be completed within a time that would result in a practical legal effect upon the parties. See id. ,
W.J.C. argues that in a sec. 51.20 hearing, he has the right to confront the witnesses against him, including a face-to-face confrontation before the jury. Because this is a civil proceeding, however, no independent right to confront witnesses exists under the Wisconsin and United States Constitutions. The issue of telephone testimony at ch. 51 hearings is therefore essentially a challenge to the procedures used to involuntarily commit an individual. These procedures must conform to the essentials of due process. Section 51.20(5), Stats.
The approach for analyzing a procedural due process claim is set out in Mathews v. Eldridge, 424 U.S. 319 (1976). The test involves balancing three factors: 1) The private interest affected by the official action, 2) the risk of erroneous deprivation of the interest through the procedures used and the probable value of additional or substitute procedural safeguards, and 3) the government’s interest. Id. at 335. The Mathews approach is appropriate to analyze the validity of a state’s mental commitment procedure under a procedural due process challenge. Parham v. J.R., 442 U.S. 584, 599-600 (1979).
We recognize that W.J.C. has a substantial liberty interest at stake. He faces a “massive curtailment” of his rights. See Humphrey v. Cady, 405 U.S. 504, 509 (1972). He loses his freedom for up to six months and suffers the social stigma attached to being involuntarily committed to a mental institution. W.J.C.’s interests, however, are ultimately served if he is in fact a proper subject for treatment.
The use of telephone testimony poses only a slight risk that W.J.C. will be erroneously deprived of his *241-liberty. The jury is unable to visually observe the doctor’s demeanor when he testifies by telephone. This inability to visually observe the doctor might arguably cause the jury to err in finding the facts. The content of the doctors’ testimony is essentially medical in character : Whether the individual is mentally ill and whether he is a proper subject for treatment. See Parham, 442 U.S. at 609-10.
The probable value of requiring the doctors to be physically present in the courtroom to testify is minimal. These witnesses are court-appointed examining physicians. See sec. 51.20(9), Stats. They are qualified as independent experts and by statute may neither be related to the individual by blood or marriage nor have an interest in the individual’s property. See id.
The government has several interests at stake. Like W.J.C., it is interested that the jury correctly find the facts. The government wants to protect the community from dangerous, mentally ill individuals, see Addington v. Texas, 441 U.S. 418, 426 (1979), while confining the use of costly mental commitment facilities to only those individuals who are proper subjects for mental health treatment. See Parham, 442 U.S. at 604-05 (2505). From the record, it is difficult to determine the fiscal and administrative burdens that in-court testimony, the alternative to telephone testimony, would entail. The court can take judicial notice, however, that the costs of securing experts, especially from another area, are considerable.
Our balancing of the Matthews factors leads us to conclude that permitting ch. 51.20(9) examining physicians to testify by telephone did not violate W.J.C.’s due process rights. The first factor, the nature of the interest at stake, weighs heavily in W.J.C.’s favor. The other factors, however, weigh in favor of permitting telephone testimony. Telephone testimony poses only a *242slight risk to the correctness of the jury’s fact finding. The only aspect of the fact finding process lost by telephone testimony is the jury’s ability to observe the doctor’s demeanor. Given the doctors’ neutrality, the probable value of in-court testimony does not justify the fiscal and administrative burdens in-court testimony would impose. We therefore affirm the order committing W.J.C.
By the Court. — Order affirmed.