The self-insured employer appeals from the compensation judge’s award of temporary partial disability benefits and from certain findings that it contends exceeded the narrow scope of the issue presented at the expedited hearing under Minn. Stat. § 176.238.  We affirm the judge’s award of temporary partial disability benefits and vacate Findings 6 and 7 as unnecessary to the judge’s decision.

On May 12, 2009, Judith Tooker [the employee] sustained an admitted injury to her left shoulder and elbow in the course of her work as a proofer in the art department of Taymark Corporation [the employer], a manufacturer of various promotional and personalized items for businesses and schools.  The employee’s job, which she had performed for the past twelve years, entailed sorting, copying, and preparing orders for the production artists, tasks that frequently required repetitive lateral arm movements and overhead reaching.  On the date of her injury, the employee was fifty-nine years old and was earning a weekly wage of $560.23, and the employer was self-insured against workers’ compensation liability.

The employee first sought treatment for her injury on May 12, 2009, with Dr. Paul Sandager at the Allina Forest Lake Clinic.  She described the gradual onset of left elbow and shoulder problems, and Dr. Sandager diagnosed a work-related rotator cuff syndrome and epicondylitis of the elbow.  He recommended ibuprofen and arranged for physical therapy.  About a month later, the employee returned to the clinic and saw her primary care physician, Dr. Gary Mayer, who noted the employee’s ongoing symptoms and her failure to benefit from physical therapy.  Dr. Mayer recommended that the employee stay home from work entirely for the next two weeks, and on June 10, 2009, the employer commenced payment of temporary total disability benefits.

When she returned to see Dr. Mayer on June 26, 2009, the employee reported significant improvement in her symptoms.  The doctor assessed work-related tendonitis and released the employee to go back to work with activity modifications, including limiting her workday to four hours.  By this time, however, the employer was in the throes of its usual seasonal slowdown and did not have work for the employee, and it continued to pay temporary total disability benefits through August 26, 2009.

At the employer’s request, the employee was seen for an independent medical exam [IME] by orthopedic specialist Dr. Scott McPherson on July 21, 2009.  In a report dated August 4, 2009, Dr. McPherson diagnosed a work-related left shoulder tendonitis and impingement condition that had resolved by the time of his exam, together with some residual radial tunnel and lateral epicondylitis symptoms.  He recommended an additional four to six weeks of therapy for the employee’s elbow condition, together with a worksite ergonomic evaluation to try to minimize future stress and strain to the left arm.  It was his conclusion, however, that she had recovered sufficiently to return to full unrestricted work activities and activities of daily living.

Dr. Mayer treated the employee’s left elbow with a cortisone injection on July 29, 2009, and he released her to return to work four hours a day on August 27, 2009.  Shortly thereafter, the employer obtained the recommended ergonomic evaluation, and changes were made to the worksite to minimize the employee’s reaching and stretching with her left arm.  The employee’s job became less repetitive after that, and work provided by the employer was compatible with restrictions identified by her treating doctor.  About this same time, the employee began receiving rehabilitation services from Qualified Rehabilitation Consultant [QRC] Mary Beth Solum, who prepared a rehabilitation plan calling for the QRC to facilitate a return to work with the employer.

Despite the employee’s four-hour work schedule, changes to her work station, and rehabilitation assistance, her left shoulder and forearm complaints continued.  Dr. Mayer therefore arranged for an orthopedic evaluation with Dr. David Falconer.  QRC Solum attended the appointment with the employee on October 29, 2009, and provided Dr. Falconer with Dr. McPherson’s IME report.  Dr. Falconer disagreed with Dr. McPherson’s left shoulder assessment and diagnosed instead an ongoing subacromial bursitis, as well as a mild tennis elbow condition.  He administered a cortisone shot to the employee’s subacromial bursa, recommended additional therapy for her shoulder, and discussed the employee’s work environment in detail with the QRC.

Because the employee did not obtain any lasting relief from the cortisone shot, Dr. Falconer recommended an MRI scan and an evaluation by a shoulder specialist.  The MRI, obtained on January 11, 2010, showed inflammatory changes in both the supraspinatus and the infraspinatus tendons, as well as apparent partial-thickness tearing of the undersurface of the supraspinatus tendon.  The employee was then examined by Dr. David Kittleson on March 11, 2010, when she reported to the doctor that an ergonomic evaluation of her work station had been helpful and that she had been avoiding outstretched or above shoulder height work.  Dr. Kittleson reviewed the employee’s x-rays and MRI scan, and he diagnosed a work-related left shoulder chronic impingement syndrome that had been caused by the employee’s repetitive retrieving and replacing of catalogs above shoulder height.  He administered another shoulder injection, recommended rotator cuff exercises, limited the employee’s lifting to two pounds, and continued her restriction to a four-hour work day.  A week later, the employee saw Dr. Falconer in follow-up regarding her left elbow symptoms.  Because of her persisting symptoms, the doctor recommended an EMG and an MRI of the elbow to rule out the possibility of referred pain from the cervical spine.

The employee was reexamined for the employer by Dr. McPherson on March 16, 2010.  In a report dated April 1, 2010, Dr. McPherson diagnosed persistent proximal forearm symptoms, most consistent with radial tunnel symptomatology, which he related to the employee’s May 12, 2009, work injury.  He continued to believe, however, that her left shoulder injury had been a temporary aggravation that had resolved.  Dr. McPherson agreed that the employee’s MRI scan correlated with an impingement syndrome diagnosis, but he attributed her ongoing left shoulder symptoms to a degenerative condition that was not work related.  He agreed with the recommendation of an EMG and an MRI scan, but he still concluded that, even with her ongoing symptoms, the employee should be able to perform full-time clerical-type activities.

Shortly after Dr. McPherson issued his report, the employer requested that the employee return to work on an eight hour per day basis.  The employee attempted to comply with the employer’s request and did in fact increase her hours between mid April and the end of June.  After that attempt, however, the employee reported increased symptoms and an inability to work a full eight-hour day.  On April 20, 2010, the employer served a Notice of Intention to Discontinue [NOID] the employee’s temporary partial disability benefits, on grounds that the employee had returned to work on March 20, 2010, at full wage.

On April 30, 2010, Dr. Falconer noted that the employee’s MRI confirmed “a high-grade partial thickness lesion of at least 50% of the extensor origin at the lateral elbow consistent with a severe lateral epicondylitis.”  The EMG study was reported as showing no evidence of nerve injury consistent with the employee’s symptoms.  Dr. Falconer administered a radial tunnel nerve block, continued the employee’s work restrictions, and released her to work four to eight hours a day as tolerated.

On May 4, 2010, Dr. McPherson reviewed the recent MRI and EMG reports and issued a supplemental report, in which he reasserted his opinion that the employee was capable of working a full eight-hour day and, in particular, of performing the clerical duties assigned by the employer.

The employee’s objection to discontinuance came on for an expedited hearing before a compensation judge on July 21, 2010.  At the outset of the hearing, the judge clarified that the sole issue for her determination was whether the employee, given her condition and situation at work, was able to work up to eight hours a day.  The employer had paid benefits through April 25, 2010, and the employee was only claiming temporary partial disability benefits through June 25, 2010.  The employee testified that she had tried to increase her hours as requested by the employer but that, as she did so, her elbow and shoulder symptoms had increased.  She testified that she had worked as much as she could but that she was ultimately unable to achieve an eight-hour day.  The employee acknowledged that the work provided by the employer was within her physical restrictions and that she was allowed to pace herself, to take breaks as necessary, and to stretch as needed.  She acknowledged also that, following the ergonomic evaluation, she was no longer required to engage in overhead reaching or repetitive use of her left arm.  She testified that she had no explanation, therefore, as to why her symptoms worsened with working additional hours.  She only knew, she testified, that, between the end of March and the end of June, she could not have worked more than she did work.

In a findings and order issued August 19, 2010, the compensation judge determined that the employee was unable to perform full-time work with the employer, due to the effects of her work-related upper extremity condition, and that she was entitled to temporary partial disability benefits between April 25, 2010, and June 25, 2010, based upon her actual earnings.  In the course of her decision, the judge also articulated what she understood to be the employee’s left shoulder diagnosis, and she noted some possible treatment options for that shoulder, as recommended by Dr. Kittleson.  The employer appeals.

On appeal, the Workers’ Compensation Court of Appeals must determine whether “the findings of fact and order [are] clearly erroneous and unsupported by substantial evidence in view of the entire record as submitted.”  Minn. Stat. § 176.421, subd. 1 (2010).  Substantial evidence supports the findings if, in the context of the entire record, “they are supported by evidence that a reasonable mind might accept as adequate.”  Hengemuhle v. Long Prairie Jaycees, 358 N.W.2d 54, 59, 37 W.C.D. 235, 239 (Minn. 1984).  Where evidence conflicts or more than one inference may reasonably be drawn from the evidence, the findings are to be affirmed.  Id. at 60, 37 W.C.D. at 240.  Similarly, findings of fact should not be disturbed, even though the reviewing court might disagree with them, “unless they are clearly erroneous in the sense that they are manifestly contrary to the weight of evidence or not reasonably supported by the evidence as a whole.”  Northern States Power Co. v. Lyon Food Prods., Inc., 304 Minn. 196, 201, 229 N.W.2d 521, 524 (1975).

The employer contends first that the judge’s finding that the employee was unable to work full-time hours due to the effects of her work injury is unsupported by substantial evidence.  The employer notes that the employee testified that, following the ergonomic evaluation in September 2009, she barely used her left arm at work, that her work duties were within her physical restrictions, and that she was able to pace herself, stretch, or take breaks as necessary.  The employer argues that the employee’s testimony that, despite all of the accommodations that had been made, she still was unable to work a full day, is simply not credible.  What is more, the employer contends, neither Dr. Falconer nor Dr. Kittleson had an accurate understanding of the job duties performed by the employee after August 2009.  In their reports, both doctors continued to refer to the employee’s lifting of catalogs over her head, an activity that the employee had not performed in over a year, and, as such, the employer argues, both doctors’ opinions as to the number of hours that the employee was capable of working were flawed and without foundation.  Only Dr. McPherson, the employer argues, had a clear understanding of the employee’s job duties following her return to work in August 2009.  The employer acknowledges that Dr. McPherson did feel that the employee was in need of work restrictions, but the employer notes that the doctor indicated that, given the type of problems that the employee has in her shoulder and elbow, there was no reason why she could not perform clerical work up to eight hours per day within those restrictions.  Therefore, the employer contends, because the employee’s testimony was not credible, and because the opinions of the treating doctors lacked foundation, the employer should be allowed to discontinue the employee’s temporary partial disability benefits.  We are not persuaded.

The compensation judge accepted the opinion of Dr. Falconer, that the employee should work within her restrictions between four to eight hours per day, as she is able to tolerate.  Where a judge’s determination is based upon a clear choice between differing medical opinions, this court normally affirms where the opinion relied upon had adequate foundation.  See Nord v. City of Cook, 360 N.W.2d 337, 37 W.C.D. 364 (Minn. 1985).  Dr. Falconer obtained a history from the employee, conferred with the employee’s QRC regarding modifications to the employee’s work station, reviewed both of Dr. McPherson’s IME reports, and had access to the records of his associate, Dr. Kittleson, who referenced the ergonomic evaluation in his March 11, 2010, office note.  We find no merit to the employer’s argument that either Dr. Falconer or Dr. Kittleson was somehow under the assumption that the employee continued to perform the same work activities she had been performing before May 12, 2009.  Throughout his course of treating the employee, Dr. Falconer recommended restrictions against those very activities.  The judge did not err in relying upon Dr. Falconer’s opinions.

In addition to medical opinions, a judge may base his or her conclusions on other reliable evidence in the record.  See Reimer v. Minnit Tool/M.I.T. Tool Corp., 520 N.W.2d 397, 51 W.C.D. 153 (Minn. 1994).  The judge’s decision here was based also on the employee’s testimony associating the worsening of her shoulder and elbow symptoms with the increase of her hours at work.  The judge credited that testimony even while noting that the work offered by the employer was within the employee’s physical restrictions and even while noting that the employee’s work station had been appropriately modified following an ergonomic evaluation.  The employee is the person most familiar with the severity of his or her symptoms, and the judge in this case did not err in relying on the employee’s testimony.  See Brening v. Roto-Press, Inc., 306 Minn. 562, 237 N.W.2d 383, 28 W.C.D. 225 (Minn. 1975).  Assessment of a witness’s credibility is the unique function of the trier of fact.  See Brennan v. Joseph G. Brennan, M.D., 425 N.W.2d 837, 839-40, 41 W.C.D. 79, 82 (Minn. 1988) (citing Spillman v. Morey Fish Co., 270 N.W.2d 781, 31 W.C.D. 187 (Minn. 1978).

Concluding that it is supported by substantial evidence in the record, we affirm the judge’s award of temporary partial disability benefits.

The employer argues also that the only issue before the judge at the expedited hearing was whether the employee was capable of working a full eight-hour work day during the period April 25 through June 25, 2010.  The judge, it asserts, went beyond this inquiry to make factual findings regarding the nature and extent of the employee’s left shoulder injury.  Because the issues were improperly expanded, it argues, the employer did not have fair notice and opportunity to defend on that issue.  We agree.

It was known at the time of the expedited hearing below that the nature and extent of the employee’s left shoulder injury remained in dispute but not at issue before the judge.  Nevertheless, at Finding 6 the judge proceeded to make a finding as to the employee’s left shoulder diagnosis in keeping with a diagnosis of Dr. Kittleson in a June 23, 2010, narrative report, and at Finding 7 she articulated Dr. Kittleson’s recommendation as to treatment should the employee’s symptoms persist.  While the judge did not expressly concur in that diagnosis or find it causally related to the employee’s work injury, and while her articulation of that treatment recommendation is not a finding that such treatment is reasonable and necessary, such conclusions are arguably implicit when Findings 6 and 7 are read in the context of the remaining findings.  Because the parties had specifically identified the narrow issue for the judge’s determination, and because it was unnecessary to state the employee’s left shoulder diagnosis or to address proposed treatment for the shoulder, we vacate Findings 6 and 7 of the judge’s findings and order.