The employee appeals from the compensation judge’s determination that the employee failed to establish a work-related injury to her right shoulder as well as the judge’s denial of the employee’s claim for temporary total disability benefits and medical treatment.  We affirm.

Nancy Lara, the employee, began working for Volunteers of America, the employer, as an assistant at Stepping Stones, a group home for disabled adults on April 29, 2010.^[1]  The employee’s job duties involved assisting the residents at the home with activities of daily living, including cooking, cleaning, passing out medications, and personal assistance with bathing, dressing, and transferring residents.

The employee claimed that she sustained a right shoulder injury while transferring a resident of the home on June 11, 2010.  The employee testified that she and her co-worker, Jessica Valerius, were transferring a resident from his wheelchair to his stander when the patient lost his balance, causing the employee to tear her right rotator cuff.  She testified that she mentioned to Ms. Valerius that her shoulder “really hurt” immediately following the incident but “I went on and did my work for the rest of the night . . . .”^[2]  The next day, the employee went to the emergency room at Fairview Northland Regional Healthcare.  While en route, the employee called the employer and spoke with the lead person on the shift, Beth Totzke.  On the way home from the emergency room, the employee stopped at Stepping Stones to fill out a first report of injury.  The handwritten report indicated that the employee was sore when she lifted a resident named Gary out of a chair into a stander; that her chest was sore again when she moved a resident named Willy in bed and out of his bath chair; and that she experienced a sore right shoulder, wrist, hand numbness, and chest pain.

The emergency physician report indicates that the employee was admitted to Fairview Northland Regional Healthcare on June 12, 2010, at 1:50 p.m., for chest pain from stress at work.  The report also indicates that a work note was provided to the employee, but that note was not part of the record at hearing.  The employee testified that the note took the employee off work until she could see her doctor.  The report also references a patient history of a rotator cuff tear with surgery in 2009.^[3]  The employee did not return to work on June 12, 2010, and on June 15, 2010, the employee was terminated from her employment with Volunteers of America.

On June 14, 2010, the employee was treated at her family practice clinic to check her medications and to follow up from her emergency room visit for chest pain, which ruled out a myocardial infarction.  The employee reported that it may have been anxiety or that she had re-torn her rotator cuff.  The employee sought treatment at the St. Cloud Hospital emergency room on June 17, 2010, and gave a history of injuring her right shoulder at work a week ago while lifting a patient into bed.  The employee was referred to her orthopedic surgeon, Dr. Matthew Hwang.

On June 25, 2010, the employee was evaluated by Dr. Hwang at St. Cloud Orthopedic Associates, and reported an injury that occurred when she lifted a patient out of a wheelchair.  The employee reported pain over the top of her right arm, the superior and posterior aspect of the right arm, neck pain, and pain radiating down her right arm into her right hand.  She had limited range of motion, tenderness, and weakness on rotation.  Dr. Hwang recommended an MRI and also took the employee off work until further notice.  The employee underwent the MRI on July 2, 2010, which indicated post-operative changes from the previous rotator cuff repair with recurrent full thickness tear of the supraspinatus tendon.  The MRI report also indicated a history of a June 11, 2010, injury while lifting a heavy box.  After the MRI, Dr. Hwang diagnosed a recurrent tear of the supraspinatus into the infraspinatus.  On August 8, 2010, Dr. Hwang performed an arthroscopic surgery for repair of the employee’s large re-tear of the rotator cuff.  The post-operative report indicates the employee’s history as right shoulder pain after a fall.  The employee was referred for physical therapy.  At the initial assessment, the employee reported being injured while transferring a patient.^[4]

The employer and insurer denied liability for the employee’s injury on the basis that the employee’s co-workers disputed that the employee had performed any transfers on the alleged day of injury.  On August 4, 2010, the employee filed a claim petition seeking temporary total disability benefits from and after June 11, 2010, permanent partial disability benefits to be determined, medical expenses, and rehabilitation services.

On January 3, 2011, the employee was evaluated by Dr. Michael D’Amato at the employer and insurer’s request.  Dr. D’Amato opined that the employee’s surgery was reasonable and necessary, that the employee was not at maximum medical improvement, that the employee had an underlying chronic pain condition, that the employee had work restrictions, and that the employee should undergo a conditioning program.  He also noted that the employee’s history of the injury did not match the histories given in the medical records.

On March 4, 2011, the employee was evaluated by Dr. Robert Wengler, who diagnosed the employee with chronic rotator cuff problems with evidence of persistent rotator cuff incontinuity.  The employee reported to Dr. Wengler that she injured her right shoulder when she and another employee were transferring a client from a wheelchair to a stander.  Dr. Wengler opined that the employee could not return to work as a licensed practical nurse and that she probably could only perform left-handed work with the possibility of using her right hand as a post.  Dr. Wengler also rated the employee for permanent partial disability.

A hearing was held on April 1, 2011, before Compensation Judge Kathleen Behounek.  The compensation judge found that the employee did not sustain a work-related injury to her right shoulder on June 11, 2010.  The employee appeals.

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.^[5]  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.^[6]  Findings of fact are clearly erroneous if the reviewing court, looking at the entire evidence, is left with a definite and firm conviction that a mistake has been committed.^[7]  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 the evidence or not reasonably supported by the evidence as a whole.”^[8]

The employee has the burden of proving, by a preponderance of the evidence, that an alleged work-related injury arose out of and in the course of her employment.^[9]  Such evidence, presented at a hearing, includes witness testimony and documentary evidence through medical records and other reports.  The employee argues that the compensation judge erroneously applied the burden of proof by finding that the employee had not proven that she had injured herself at work where there was no evidence that the injury had occurred elsewhere.  We disagree.  It is the compensation judge’s responsibility to weigh the evidence and to assess the probative value of witness testimony.  Where the evidence submitted reasonably permits different inferences, the choice of inference to be drawn rests with the compensation judge as the factfinder.^[10]

Resolution of this case rests primarily on the compensation judge’s evaluation of the credibility of the witnesses.  The compensation judge determined that the employee’s testimony was not credible and found that the employee failed to establish that she sustained a work-related injury on June 11, 2010.  The employee argues that the evidence does not support the findings.  In making her claim for workers’ compensation benefits, the employee testified under oath that she hurt her right shoulder at work on June 11, 2010.  In support of her testimony, the employee provided the expert medical opinion of Dr. Wengler, medical records from six healthcare providers, a grocery receipt from Teal’s Market, a recorded employee statement, and the employer’s work schedule.  The employer and insurer introduced testimony from the employee’s co-workers, the expert medical opinion of Dr. D’Amato, additional medical records, and the first report of injury.  The compensation judge made her determination of the case based on her review of the testimony and the documentary evidence, and applied the appropriate burden of proof to the facts in this case.

At the hearing, the employee testified that she injured her right shoulder while lifting a resident named Terry.  The handwritten first report of injury states that the employee was sore when she lifted a resident named Gary out of a chair into a stander and that her chest was sore again when she lifted a resident named Willy in bed and out of a bath chair.^[11]  The employer and insurer offered testimony disputing the timeline of events and the mechanism of the injury offered by the employee.  Co-worker Jessica Valerius testified that the employee did not transfer Terry on June 11, 2010, and that the transfer was performed by herself and another co-worker, Beth Totzke, who both assisted Terry from his wheelchair to a stander at approximately 3:15 p.m.  Co-worker Beth Totzke’s testimony^[12] was consistent with that of Jessica Valerius.  Both co-workers testified that the employee did not mention she hurt her shoulder while assisting a resident on June 11, 2010.

The employee’s testimony is at variance with the testimony of her co-workers.  The assessment of witness credibility is the function of the fact-finder.  Findings based on that assessment will generally not be reversed in the absence of clear error.^[13]  Weighing the credibility of a witness and reaching conclusions as to the mechanism of an injury is a determination to be made by the compensation judge after considering the evidence.  The compensation judge assessed the testimony of the witnesses and found the co-workers’ testimony more persuasive.  Substantial evidence supports the compensation judge’s finding that the employee’s testimony was not credible.

The employee insists that the judge’s finding that “[t]here was no indication in the emergency room records that the employee sought treatment due to a work injury to her right shoulder at work”^[14] is completely erroneous based on the June 12, 2010, emergency room report documenting that the employee reported that she was injured yesterday with increased stress at work.  We disagree.  On June 12, 2010, the employee presented herself at the Fairview Northland Regional Healthcare emergency room with a chief complaint of “chest pain” beginning yesterday, still present and persistent.  The intake record indicates chest pain with right arm numbness, but does not indicate any specific injury to the employee’s right shoulder occurring while she was at work.  The report documents stress at work and describes steady persistent right side chest pain into right shoulder that was relieved by nothing and worsened by deep breathing.^[15]  Further explanation of the presented condition is set out in abbreviated handwritten notes that diagram an onset of chest pain beginning the day before and progressing to a steady persistent pressure in her right side of the chest with pain radiating into the right shoulder.  The discharge instructions reference a work note given to the employee, but that note is not part of the record so it is unknown whether it allowed the employee to return to work or took the employee off of work.  The report did not specify a right shoulder injury that occurred at work.  The judge’s finding, that the emergency room records do not indicate that the employee was seeking treatment for a work-related injury to her right shoulder, is supported by substantial evidence.

Several medical providers who treated the employee’s right shoulder symptoms after June 15, 2010, outlined different histories and gave different accounts on the mechanism of the employee’s injury.  A few of the records, however, are consistent with the history given by the employee at the hearing.  The June 17, 2010, St. Cloud hospital report indicated that the employee was hurt lifting a patient into bed; the June 25, 2010, St. Cloud Orthopedic Associates report indicates that the employee stated that she was injured when she lifted a patient out of a wheelchair; the July 2, 2010, MRI report indicates that the employee was injured while lifting a heavy box; and the August 5, 2010, surgical report indicates that the employee was hurt in a fall.^[16]  Dr. D’Amato’s independent medical evaluation report also noted the inconsistencies in the employee’s histories contained in the medical records.

The compensation judge noted the employee’s testimony on why she sought emergency treatment at the Fairview medical facility and compared that with the emergency physician report.  The judge also reviewed the first report of injury completed by the employee and compared the report to the testimony of the employee and co-workers.  Substantial evidence supports the judge’s conclusion that the histories provided by the employee to various medical providers were inconsistent with her testimony at hearing and with the information provided by the employee in her first report of injury.

The employee also argues that Dr. D’Amato’s opinion is not reliable since his review of the employee’s medical history erroneously states that the employee did not seek treatment at an emergency room until June 17, 2010, arguing that a doctor's opinion regarding causation which is based on an inadequate factual foundation is of little evidentiary value.^[17]  The fact that the employee sought treatment on June 12, 2010, rather than June 17, 2010, does not render Dr. D’Amato’s opinion without foundation, but goes to the weight to be afforded the doctor’s opinion rather than its admissibility.  Dr. D’Amato had adequate foundation to render his expert opinion.  It is the responsibility of the compensation judge, as the trier of fact, to select between conflicting medical opinions.^[18]  The compensation judge did not err by relying on Dr. D’Amato’s opinion.^[19]

As presented by the parties, this case was primarily one of witness credibility.  Contrary to the employee’s assertions, there is evidence in the record to refute the employee’s claim, including the emergency room report which counters the employee’s description of a work-related injury, the first report of injury which contradicts the employee’s later claim as to the name of the resident involved in the transfer, and medical records that contain different histories from the employee regarding the injury.  Based upon what the judge believed to be numerous and significant inconsistencies in the employee’s testimony and the employee’s medical records and the consistency in the co-workers’ testimony, she found the co-workers’ statements persuasive and the employee’s testimony not credible.  Absent clear error, a finding based on witness credibility will not be disturbed on appeal.^[20]  Substantial evidence supports the compensation judge’s finding that there was a lack of evidence to sustain the employee's claim that her injury occurred at work.^[21]  Accordingly, we affirm.