               IN THE SUPREME COURT OF IOWA
                              No. 09–0724

                        Filed December 16, 2011


CEDAR RAPIDS COMMUNITY SCHOOL DISTRICT
and EMC INSURANCE COMPANIES,

      Appellants,

vs.

CHRISTINE PEASE,

      Appellee.


      On review from the Iowa Court of Appeals.



      Appeal from the Iowa District Court for Polk County, Scott D.

Rosenberg, Judge.



      On further review, we address whether substantial evidence

supports the workers’ compensation commissioner’s findings of fact.

DECISION OF COURT OF APPEALS VACATED; DISTRICT COURT

JUDGMENT AFFIRMED.


      Tina M. Eick and Wendy D. Boka of Hopkins & Huebner, P.C.,

Des Moines, for appellants.



      Thomas M. Wertz and Daniel J. Anderson of Wertz & Dake, Cedar

Rapids, for appellee.
                                      2

APPEL, Justice.

         In this workers’ compensation case, we consider whether the court

of appeals properly applied the “substantial evidence” test under Iowa

Code section 17A.19(10)(f) (2009) when it reversed an award of benefits

in an appeal of a decision of the workers’ compensation commission.

Based on our review of the record, we conclude substantial evidence

supports the commissioner’s findings.         As a result, we vacate the

decision of the court of appeals and affirm the judgment of the district

court.

         I. Factual and Procedural Background.

         Christine Pease injured her right ankle when she slipped on ice

and fell in the course of her employment with the Cedar Rapids

Community School District (District) as a “job coach.” The position of job

coach involved working with disabled children, transporting them to

various locations in the community in the school van.

         Pease filed a claim with the workers’ compensation commission

seeking benefits as a result of her alleged injuries.     While the parties

stipulated that Pease suffered a right ankle injury as a result of the slip

and fall and that the injury arose within the scope of employment, the

District disputed “the nature, scope and effect of the injury.”

         Pease’s ankle injury required her to undergo two surgeries related

to the placement and removal of a screw. In addition, Pease claimed that

her fall caused her to have an altered gait, which in turn caused her to

sustain an injury to her left ankle and back. Pease further maintained

that her injuries increased her preexisting state of depression.

         At the hearing, Pease offered evidence in support of her claim that

her right ankle injury caused a change in gait which subsequently

caused injuries to her left ankle and back.      With respect to her right
                                     3

ankle, Pease offered the testimony of a physician that she suffered “a

rather significant ligamentous injury to her right ankle involving both the

deltoid and syndesmotic ligament.”       She then reported to another

physician that she began experiencing low back pain due to her altered

gait. Although Pease sought treatment for lower back pain before, her

physician noted that her back pain had become more difficult to control

after her fall. In addition, Pease reported that she began to experience

pain in her left ankle due to her altered gait.     Pease, however, had a

history of problems with her left ankle, which included a chronic tear of

ligaments and two arthroscopic surgeries prior to her slip and fall

involved in this case.

      According to Pease, after she had reached maximum medical

improvement she was asked to undergo a functional capacity evaluation.

The results of the functional capacity evaluation indicated that Pease

could stand or walk no more than fifty percent of her work shift and for

limited durations; could lift twenty pounds rarely, fifteen pounds

occasionally, and seven to eight pounds frequently; could tolerate a

maximum of ten to twelve stairs up and down once a day using handrails

for support; and should avoid ladder or step climbing greater than an

eight inch height. Her physician characterized these work restrictions as

“permanent.”

      More than four months later, the District terminated Pease’s

employment. The District stated that Pease had been unable to return to

work since her injury and, in light of the permanent restrictions, she was

unable to perform the essential functions of the position of job coach or

any other job with the District in her pay range.

      After her termination from employment, Pease became increasingly

depressed and sought medical help for this condition.        Pease had a
                                       4

history of depression prior to her work injury, but testified her

depression became much worse following the injury. She testified that

her constant pain, inability to walk, loss of her job, and her increased

stress levels all contributed to her depression and that the depression

interfered with her concentration, her sleep, and her social life.

       Pease offered expert medical testimony in support of her claim that

she suffered deeper depression as a result of her work injury.

Dr. William Stutts, a psychiatrist, concluded that Pease’s work injury

was a “substantial contributing factor[] in bringing about her current

level of depression.” Dr. Stutts asserted it was more likely than not that

the chronic pain resulting from her injuries was permanent and that the

pain would continue to contribute to Pease’s depression.              Another

physician, Dr. John Brownell, characterized Pease as suffering from a

“pretty clear case of post-surgical depression” and further stated that the

depression was a result of both the stress of the surgery and her

decreased mobility.

       Pease offered the opinion of Barbara Laughlin, a vocational expert,

in support of her claim that she was no longer employable.           Laughlin

asserted that Pease suffered a ninety to one hundred percent loss of

access to the labor market as a result of her injuries. Laughlin stated

that   Pease   would   have   great   difficulty   finding   and   maintaining

employment in light of her inability to interact appropriately with peers,

the general public, and supervisors.

       The District countered by offering evidence that tended to

characterize Pease’s injuries as less substantial.       After performing an

independent medical examination, Dr. Ray Miller opined that Pease had

an eight percent of the whole person impairment due to the right ankle

injury and the subsequent sequelae to the back and left ankle.
                                         5

          With respect to the claim of depression, the District offered

evidence from Dr. Raymond Crowe indicating that Pease’s depressive

episode was not causally connected to the injury.               Dr. Crowe later

asserted that Pease was malingering.

          The District offered a vocational report prepared by Dr. Elizabeth

Mease and Dr. Janeen Montgomery.                 They opined that Pease was

employable at the sedentary physical level and was not psychiatrically

foreclosed from employment.

          The deputy commissioner ruled in favor of Pease.           The deputy

concluded that Pease suffered “an injury to the body as a whole.”

Additionally, the deputy found that Pease’s work injury was a

“substantial contributory factor in [Pease’s] current state of depression.”

Further, the deputy held that as a result of her physical and

psychological injuries, Pease was “unable to return to any job she ha[d]

previously held.” As a result, the deputy awarded Pease permanent total

disability, accrued benefits, and reimbursement for medical expenses.

          The commissioner affirmed the decision of the deputy, but

modified and expanded on the deputy’s ruling. The commissioner noted

that the deputy had erroneously stated that Dr. Miller had assigned an

eight percent permanent disability rating to the injuries to the right

ankle, neck, lower back, and left ankle when, in fact, Dr. Miller assigned

the disability rating based only on the injuries to Pease’s lower back and

left ankle. The commissioner concluded that this error had no impact on

the case.

          The commissioner further considered whether the deputy erred in

failing     to   apportion   Pease’s   alleged   preexisting   disability.   The

commissioner noted that this issue was not raised before the deputy and

was not preserved for appeal.
                                      6

      The district court affirmed in part and reversed in part.          The

district court first concluded that the commissioner applied the

appropriate standard of review and correctly held the District failed to

preserve error on the apportionment issue.         The district court also

upheld the commissioner’s findings of fact with respect to the causation

of Pease’s mental and physical injuries.      The court observed that the

commissioner favored the findings of Dr. Miller and Dr. Stutts and

concluded that, on the whole, substantial evidence supported the

commissioner’s findings. Further, the district court held that substantial

evidence supported the commissioner’s findings regarding disability. The

court reversed, however, the commissioner’s award of medical expenses

for Pease’s neck injuries because there were no findings to establish that

the neck injuries were caused by the January 26 accident. The District

appealed, and the court of appeals reversed and remanded.

      The court of appeals held substantial evidence did not support the

commissioner’s findings on causation.          The court questioned the

reliability of Dr. Miller’s conclusions, observing that Dr. Miller’s reliance

on the history provided by Pease was misplaced because other evidence,

including    video    surveillance,   undermined      Pease’s    credibility.

Additionally, the court noted that Dr. Miller incorrectly believed Dr. Kline

opined that Pease’s back pain was caused by the January 26 accident

when, in fact, Dr. Kline concluded the opposite.        Further, the court

questioned the conclusions of Dr. Stutts, explaining that Dr. Stutts’

opinion rested, in part, on an inaccurate and incomplete history of

depression provided by Pease.         Finally, the court discussed the

conflicting evidence and Pease’s “lengthy history of symptoms” relating to

the injuries and concluded medical causation was lacking between the

January 26 accident and the injuries to Pease’s left ankle, lower back,
                                      7

and postaccident level of depression. Pease applied for further review,

which we granted.

      II. Standard of Review.

      Our decision is controlled in large part by the deference we afford

to decisions of administrative agencies.    Medical causation presents a

question of fact that is vested in the discretion of the workers’

compensation commission. See Dunlavey v. Econ. Fire & Cas. Co., 526

N.W.2d 845, 853 (Iowa 1995).          We will therefore only disturb the

commissioner’s finding of medical causation if it is not supported by

substantial evidence. See Iowa Code § 17A.19(10)(f).

      The Iowa Administrative Procedure Act defines “substantial

evidence” as follows:

      [T]he quantity and quality of evidence that would be deemed
      sufficient by a neutral, detached, and reasonable person, to
      establish the fact at issue when the consequences resulting
      from the establishment of that fact are understood to be
      serious and of great importance.

Id. § 17A.19(10)(f)(1).   When reviewing a finding of fact for substantial

evidence, we judge the finding “in light of all the relevant evidence in the

record cited by any party that detracts from that finding as well as all of

the relevant evidence in the record cited by any party that supports it.”

Id. § 17A.19(10)(f)(3). Our review of the record is “fairly intensive,” and

we do not simply rubber stamp the agency finding of fact.         Wal-Mart

Stores, Inc. v. Caselman, 657 N.W.2d 493, 499 (Iowa 2003).

      Evidence is not insubstantial merely because different conclusions

may be drawn from the evidence. John Deere Dubuque Works of Deere &

Co. v. Weyant, 442 N.W.2d 101, 105 (Iowa 1989). To that end, evidence

may be substantial even though we may have drawn a different

conclusion as fact finder. Ardnt v. City of Le Claire, 728 N.W.2d 389, 393
                                        8

(Iowa 2007); Missman v. Iowa Dep’t of Transp., 653 N.W.2d 363, 367

(Iowa 2002).         Our task, therefore, is not to determine whether the

evidence supports a different finding; rather, our task is to determine

whether substantial evidence, viewing the record as a whole, supports

the findings actually made.        See Iowa Code § 17A.19(10)(f); Schutjer v.

Algona Manor Care Ctr., 780 N.W.2d 549, 557–58 (Iowa 2010).

         III. Discussion.

         At the heart of this case is the issue of the extent to which expert

testimony constitutes substantial evidence in a workers’ compensation

claim.     Experts for the parties gave conflicting opinions regarding the

causation of Pease’s postaccident physical and psychological injuries.

The commissioner ultimately determined the expert opinions offered by

Pease were more credible and gave their opinions more weight.              The

District now asks us to hold that the opinions relied upon by the

commissioner were so flawed that they failed to constitute substantial

evidence supporting the commissioner’s findings. We decline to do so.

         Medical causation “is essentially within the domain of expert

testimony.” Dunlavey, 526 N.W.2d at 853. The commissioner, as trier of

fact, has a duty to weigh the evidence and measure the credibility of

witnesses.     Id.    The weight given to expert testimony depends on the

“accuracy of the facts relied upon by the expert and other surrounding

circumstances.” Schutjer, 780 N.W.2d at 560 (internal quotation marks

omitted). Also, an expert’s opinion is not necessarily binding upon the

commissioner if the opinion is based on an incomplete history.

Dunlavey, 526 N.W.2d at 853. Ultimately, however, the determination of

whether to accept or reject an expert opinion is within the “peculiar

province” of the commissioner.        Deaver v. Armstrong Rubber Co., 170

N.W.2d      455,     464   (Iowa   1969).    The   District   challenges   the
                                    9

commissioner’s medical causation findings relating to Pease’s left ankle

and lower back as well as her postaccident level of depression.        We

discuss each separately.

      A.    Medical Causation of Pease’s Left Ankle and Lower Back

Injuries.    The commissioner primarily relied upon the opinions of

Dr. Miller in concluding Pease’s work injury aggravated the injuries to

her left ankle and lower back.     Dr. Miller performed an independent

medical examination of Pease in March 2006.           Dr. Miller reviewed

medical records from Physicians’ Clinic of Iowa, the University of Iowa

Orthopedic Department, Dr. Brownell, Dr. Fortson, St. Luke’s Hospital,

Dr. Kline, St. Luke’s Therapy Plus, University of Iowa Psychiatry

Department, and Jennifer Bradley ARNP from Mercy Psychiatric Center.

He also had x-rays available from St. Luke’s Hospital and the Physicians

Clinic of Iowa.    In addition to reviewing Pease’s medical records,

Dr. Miller personally performed a physical examination of Pease. Based

on his review of the medical records and his personal examination,

Dr. Miller opined to a reasonable degree of medical certainty that Pease’s

left ankle and lower back injuries were aggravated by the January 26,

2005 accident.

      Dr. Miller explained that the injury to Pease’s right ankle

aggravated her “preexisting osteoarthritis of the left ankle.”   Dr. Miller

observed that Pease experienced “an increase in . . . symptoms of pain

related to weight-bearing that have continued since the time of the fall of

01/26/2005, and, therefore, are felt to be an aggravation of a preexisting

condition.” Dr. Miller’s observations of an increase in symptoms of pain

following the accident are consistent with the medical reports submitted

to him for his evaluation.
                                     10

      Pease’s ankle symptoms appeared to progress after the accident so

she returned to the University of Iowa and was evaluated by

Dr. Saltzman on March 16, 2005. Dr. Saltzman’s notes state that Pease

met with Dr. Saltzman because of a “new problem in her left ankle.”

According to the notes, Pease was “beginning to develop more problems

with the left side. . . . What has added to this is that she fell on the ice

and tore the syndesmosis and deltoid ligament on her right ankle.” After

a CT scan and radiological examination, Dr. Saltzman’s impression was

that Pease suffered central heel pain and left ankle pain.

      In April 2005, Dr. Amendola assumed the care for Pease’s left

ankle. Pease visited Dr. Amendola on three occasions between April and

August 2005. According to Dr. Amendola’s notes, Pease advised in April

that she experienced some improvement with her left ankle once she was

able to bear weight on the right. Throughout the five months, however,

Pease reported that she continued to experience pain in her left ankle.

      In December 2005, Dr. Amendola wrote a letter to the District’s

counsel. In the letter, Dr. Amendola advised he had been involved in the

care of Pease from March through August of that year “for, what appears

to be, an exacerbation of a pre-existing condition.”         Dr. Amendola

continued, explaining, “I do agree that this patient had ongoing pre-

existing problems in her ankle.      Therefore, this note is to clarify, in

writing, that in fact this was an aggravation of a pre-existing condition.”

      From this review of the record, it is apparent that substantial

evidence supports the commissioner’s finding of medical causation with

respect to the left ankle.   Dr. Miller opined to a reasonable degree of

medical certainty that the symptoms Pease experienced in her left ankle

were aggravated by the increased weight-bearing requirements stemming

from the January 26, 2005 accident. Dr. Miller’s opinion is supported by
                                    11

the reports of Dr. Saltzman and Dr. Amendola, which Dr. Miller reviewed

in formulating his opinion. Also, Dr. Amendola expressed the view that

the left ankle problems suffered by Pease following the accident were an

aggravation of a preexisting condition.

      Substantial evidence also supports the commissioner’s finding of

medical   causation   between    the      work-related   accident   and   the

aggravation of Pease’s lower back symptoms. As with the left ankle, the

commissioner relied on Dr. Miller’s opinion concluding within a

reasonable degree of medical certainty that the January 26, 2005

accident aggravated Pease’s preexisting back condition.             Dr. Miller

explained:

             Regarding Ms. Pease’s low back, for which she had a
      preexisting facet arthropathy in the lower lumbar levels,
      following her fall of 01/26/2005 she developed an increase
      in her low back symptoms that have persisted and have
      required further treatment that did not substantially
      alleviate her symptoms. I would agree with Dr. Kline’s
      assessment that Ms. Pease has had an increase in her low
      back symptoms following the work related injury of
      01/26/2005 regarding her low back, and these are related to
      the required use of crutches following surgery on her right
      ankle and alterations in her gait pattern because of the
      symptoms related to both ankles.

Dr. Miller thus attributed the aggravation of Pease’s lower back

symptoms to her altered gait and use of crutches following the injury to

her right ankle.

      The District, however, argues Dr. Miller’s opinion is suspect in part

because he relied on Dr. Kline’s assessment which, according to the

District, “was directly to the contrary” of Dr. Miller’s conclusions. The

District relies on a letter written by Dr. Kline, who began treating Pease

before her accident, in which Dr. Kline stated he “would not attribute

[Pease’s] ongoing need for treatment of her back to her ankle injury of
                                          12

01/26/2005.”        Yet Dr. Kline specifically stated that he could not

determine      within    a   reasonable    medical     certainty   that     a    causal

relationship existed between Pease’s postaccident back pain and her

right ankle injury.          Dr. Kline’s letter, therefore, does not wholly

undermine Dr. Miller’s conclusions.

      In fact, Dr. Kline’s medical records generally support Dr. Miller’s

conclusions.      In an operative report dated May 2, 2005, Dr. Kline

observed that Pease “did well after her initial epidural steroid injection in

January. However, she subsequently experienced a fall and injured her

right ankle.     This reinjured her back.          Her back pain has been more

difficult to control since that time.” (Emphasis added.) In another report

dated July 26, 2005, Dr. Kline stated:

            The patient was initially seen in the clinic in January
      2005. She underwent an epidural steroid injection. This
      resulted in marked improvement in her ankle, as well as her
      pain. However, she subsequently experienced a fall and
      reinjured her right ankle, as well as her back.

(Emphasis added.) Thus, although Dr. Kline could not opine within a

reasonable degree of medical certainty whether Pease’s postaccident

lower back symptoms were caused by the injury to her right ankle, his

medical notes are consistent with Dr. Miller’s opinion in this regard.

      The   court       of   appeals    regarded    Dr. Miller’s   expert       opinions

unreliable because Dr. Miller relied upon a “questionable” history

provided by Pease. The court noted that the evidence, including video

surveillance    footage,     directly   contradicted     Pease’s   testimony        and

undermined her credibility.             As we have stated before, however,

credibility determinations in workers’ compensation claims are within the

domain of the commissioner as trier of fact. Certainly, there are cases in

which witness testimony may be “so impossible or absurd and self-
                                    13

contradictory that it should be deemed a nullity by the court,” Graham v.

Chi. & N.W. Ry., 143 Iowa 604, 615, 119 N.W. 708, 711 (1909), but this

is no such case.

      First, Dr. Miller did not rely solely upon the history provided by

Pease in his evaluation.        Dr. Miller also performed a physical

examination of Pease and reviewed medical records detailing Pease’s

medical history. After performing the physical and reviewing the medical

records, Dr. Miller—who is a board certified orthopedic surgeon, board

certified in occupational medicine, and board certified in performing

independent medical evaluations—concluded within a reasonable degree

of medical certainty that the injury to Pease’s right ankle aggravated her

symptoms of pain in her left ankle and lower back.             The District

presented no expert opinion calling Dr. Miller’s opinions into question

within a reasonable degree of medical certainty. Thus, even if the video

surveillance raised doubts about Pease’s credibility, the commissioner

could nevertheless reasonably rely upon the opinion of Dr. Miller.

      Second, Dr. Miller’s conclusions did not change after he viewed the

video surveillance footage. Dr. Miller wrote a letter to Pease’s attorney

following a review of the surveillance videos.    In the letter, Dr. Miller

stated, “[I]t is my opinion within a reasonable degree of medical certainty,

that my report with its conclusions and impairment recommendations,

remains accurate and appropriate.”       Dr. Miller explained Pease will

experience “good days and bad days regarding her symptoms and activity

level that can affect her gait pattern and her use of ankle supports and

braces.” Thus, Dr. Miller’s opinion, which the commissioner called “in-

depth and substantiated,” was unaffected by the video surveillance

footage.
                                     14

      Third, video surveillance footage depicting a claimant performing

tasks inconsistent with the claimed disability is hardly a smoking gun.

“Although on the surface it might appear that nothing could be more

cogent and a more dramatic refutation of a disability claim than motion

pictures of a claimant jacking up a car or playing tennis,” Professor

Larson explains, “the courts have rightly observed that such evidence

must be used with great caution.”      7 Arthur Larson & Lex K. Larson,

Larson’s Workers’ Compensation Law § 127.10, at 127-46 (2010).            In

Gagliano v. Boh Brothers Construction Co., 44 So. 2d 732, 735 (La. Ct.

App. 1950), the Court of Appeal of Louisiana cautioned the use of motion

pictures and noted that a “spirit of fair play” requires motion pictures to

“reflect all activities of the subject of the pictures, and not merely

snatches or fragments.” Also, in Ferraro v. Zurcher, 79 A.2d 473 (N.J.

Super. Ct. App. Div. 1951), the Superior Court of New Jersey cautioned

against the use of heavily edited motion pictures that consolidate isolated

incidents taken over a span of three years into a fifteen minute film.

“This presentation of isolated incidents occurring at widely separated

times,” the Ferraro court explained, “gives the deceptive impression of a

continuing performance and tends to cause the viewer to infer that

petitioner has a capacity for sustained effort, which clearly is not the

fact.” Ferraro, 79 A.2d at 478; see also Lambert v. Wolf’s, Inc., 132 So. 2d

522, 527 (La. Ct. App. 1961) (admitting motion picture evidence with

caution because it failed to show rest periods, did not reflect pain, and

did not show the after effects of the subject’s activities); DeChandt v. N.D.

Workers Comp. Bureau, 452 N.W.2d 82, 85 (N.D. 1990) (holding workers’

compensation bureau’s reliance on audio and videotapes failed to

adequately explain reasons for disregarding medical evidence).
                                     15

      In this case, the video surveillance footage is not of such a

character as to completely undermine Pease’s credibility.        All told, the

video contains less than forty minutes of Pease walking and shopping

during the two-year period between her work injury and the hearing.

The surveillance footage is fragmented, depicting Pease for brief intervals

of time. Even the longest segment, which lasted less than a half hour, is

not continuous and is missing nearly five minutes. We acknowledge the

video does tend to impeach the credibility of Pease as it shows she did

not always wear her brace and, on at least one occasion, wore sandals.

It was the duty of the commissioner, however, to weigh the evidence as a

whole, taking into consideration the credibility of the witnesses, and

determine whether Pease’s right ankle injury aggravated the symptoms of

Pease’s left ankle and lower back.        See Burns v. Bd. of Nursing, 495

N.W.2d 698, 699 (Iowa 1993) (“Because review is not de novo, the court

must not reassess the weight to be accorded various items of evidence.”).

Viewing the record as a whole, the commissioner may have reasonably

concluded the fragmented video surveillance footage did not entirely

undercut Pease’s credibility or the opinions of Dr. Miller.

      Substantial evidence therefore supports the commissioner’s finding

of medical causation with respect to Pease’s left ankle and lower back.

The court of appeals erred in holding otherwise.

      B.      Medical Causation of Pease’s Postaccident Level of

Depression.      We also conclude substantial evidence supports the

commissioner’s    finding   that   Pease’s   work   injury    aggravated   her

depression.    The commissioner and deputy commissioner principally

relied on the medical opinions of Dr. Stutts. Dr. Stutts concluded Pease

suffered from Major Depressive Disorder, Recurrent following her work

accident.   He opined to a reasonable degree of medical certainty that
                                    16

Pease’s work injury was “a substantial factor in bringing about her

current level of depression” and her “chronic pain was more likely than

not permanent and would continue to contribute to [Pease’s] level of

depression.” “Situational stress and chronic pain as well as limitations

from injuries and ongoing litigation,” Dr. Stutts explained, “have

exacerbated anxiety and worsened mood substantially.”          Further, he

noted that “[c]hronic pain and depression are intimately linked and serve

to exacerbate one another” and “the chronic pain in Ms. Pease’s ankles is

a substantial contributing factor in her depression.”

      Dr. Stutts’ conclusions were consistent with those of Jennifer

Bradley, an advanced nurse practitioner under the supervision of

Dr. Stutts.   Following the accident, Pease met with Bradley eight

separate times between June 13, 2005, and August 30, 2006. Bradley’s

notes of the initial diagnostic evaluation state, “Since [Pease] had ankle

surgery, her depression worsened dramatically.”            Based on her

evaluation of Pease, Bradley’s impression was that Pease suffered Major

Depressive Disorder, Recurrent and Severe.

      Moreover, Dr. Brownell, Pease’s family doctor, met with Pease on

May 26, 2005, and his medical notes from the visit state that Pease was

“[v]ery tearful” and that she felt “down, depressed and sad.” The notes

also state that Pease’s symptoms of depression “all started after the

problems with her right ankle.”     Dr. Brownell stated that this was a

“[p]retty clear case of post-surgical depression.”      Explaining further,

Dr. Brownell noted,

      I certainly think this is a Workman’s Compensation issue
      and is caused by the surgery of her ankle, and the injury
      itself. I think it’s a combination of both the stress of the
      surgery and also her decreased mobility etc, as a result of
      the actual injury itself.
                                   17

Based on his observations and conclusions, Dr. Brownell prescribed

Pease antidepressant medication and referred her to Dr. Stutts.

      Not all medical professionals agreed with the conclusions of

Dr. Stutts, Bradley, and Dr. Brownell, however.          Dr. Crowe, a

psychiatrist with the University of Iowa, evaluated Pease once in

November 2005. Dr. Crowe summarized his conclusions in a letter to

EMC Insurance Companies dated December 19, 2005.           In the letter,

Dr. Crowe stated that he diagnosed Pease with Major Depressive

Disorder, but concluded that the accident did not aggravate her

depression because her major depressive disorder began a year before

the injury (April 2004) and that the current episode did not occur until

three months after the injury.    Dr. Crowe subsequently changed his

diagnosis to malingering after viewing the video surveillance footage

discussed above.   In light of his finding of malingering, Dr. Crowe no

longer had confidence in his previous diagnosis given what he perceived

to be the questionable history provided by Pease. Dr. Crowe also stated,

however, that he could not exclude a diagnosis of depression.

      Dr. Stutts and Bradley rejected Dr. Crowe’s conclusions. “We are

without a doubt,” they explained in a letter to Pease’s attorney, “in

agreement that Ms. Pease is not malingering as Dr. Crowe charges.”

Dr. Stutts and Bradley also noted that malingering occurs in the absence

of pathology, and because Pease had been diagnosed with Major

Depressive Disorder, she was not malingering. Accordingly, despite Dr.

Crowe’s observations, they did not change their diagnosis of Major

Depressive Disorder, Recurrent, and Dr. Stutts did not alter his

conclusion that Pease’s work injury aggravated her depression.

      The commissioner was thus confronted with a classic “battle of the

experts.” On the one hand, an independent psychiatric evaluation found
                                    18

Pease to be malingering. On the other hand, Dr. Stutts diagnosed Pease

with Major Depressive Disorder, Recurrent, and he concluded that the

work injury aggravated Pease’s depression.     The deputy commissioner

ultimately found Dr. Stutts’ opinion more credible and explained that

Dr. Crowe’s revised diagnosis of malingering “was not based on any

additional treatment of the claimant” and “ignore[d] that the claimant

ha[d] actual underlying physical pathology and diagnosed recurrent

major depressive disorder.”   He also rejected Dr. Crowe’s diagnosis of

malingering because Dr. Crowe’s opinion “demonstrate[d] that [Pease]

was reasonably stable at the time of injury and worsened following.” The

commissioner adopted these findings.

      As we have explained, the commissioner, as fact finder, is

responsible for determining the weight to be given expert testimony.

Sherman v. Pella Corp., 576 N.W.2d 312, 321 (Iowa 1998).               The

commissioner is free to accept or reject an expert’s opinion in whole or in

part, particularly when relying on a conflicting expert opinion. Id.; see

Huwe v. Workforce Safety & Ins., 746 N.W.2d 158, 161–62 (N.D. 2008)

(“When confronted with a classic ‘battle of the experts,’ a fact-finder may

rely upon either party’s expert witness.”). The courts, in their appellate

capacity, “are not at liberty to accept contradictory opinions of other

experts in order to reject the finding of the commissioner.”       Dille v.

Plainview Coal Co., 217 Iowa 827, 846, 250 N.W. 607, 615 (1933); see

Hinrichs v. Davenport Locomotive Works, 203 Iowa 1395, 1397, 214 N.W.

585, 586 (1927). In this case, the commissioner relied on the opinion of

Dr. Stutts who concluded Pease’s work injury aggravated her depression.

Dr. Stutts’ conclusions were supported by the opinions of two other

medical professionals who met with Pease several times following her
                                    19

accident.   Based on the record before us, we are satisfied that the

commissioner’s findings are supported by substantial evidence.

      The court of appeals, however, concluded that Dr. Stutts’ opinion

did not amount to substantial evidence because it was based in part on

the inaccurate and incomplete history of Pease’s depression. Specifically,

the court of appeals noted that Pease “downplayed the depression she

experienced prior to her right ankle injury” when providing her history to

Dr. Stutts. Also, the court stated that Dr. Stutts was “not told of the

depression and medications taken before the January fall, nor was he

aware of her reports to Dr. Eyanson on the day before the injury.”

      Before Dr. Stutts rendered his opinion, Pease met with Bradley for

an initial diagnostic evaluation.   Bradley’s impression was that Pease

suffered from Major Depressive Disorder, Recurrent.       The diagnostic

criteria for Major Depressive Disorder, Recurrent includes the presence

of two or more Major Depressive Episodes.          American Psychiatric

Association, DSM-IV-TR Mental Disorders: Diagnosis, Etiology, and

Treatment 738 (Michael B. First & Allan Tasman eds. 2004). According

to the Diagnostic and Statistical Manual of Mental Disorders-IV, “To be

considered separate episodes, there must be an interval of at least 2

consecutive months in which criteria are not met for a Major Depressive

Episode.”   Id.   Thus, although Bradley noted Pease’s past psychiatric

history was Pease “took Lexapro for a short time because she felt as

though she was having some hormonal imbalance,” Bradley’s initial

impression that Pease had Major Depressive Disorder, Recurrent,

suggests Bradley was aware that Pease suffered at least one previous

Major Depressive Episode.

      Even assuming Pease provided inaccurate and incomplete history

of her depression, Dr. Stutts was provided materials detailing Pease’s
                                         20

prior history with depression. Not insignificantly, Dr. Stutts received the

December 19, 2005 letter in which Dr. Crowe explained Pease had been

diagnosed with Major Depressive Disorder as early as April 12, 2004.

Dr. Stutts also received the records of Dr. Fortson from 2004, which

stated that Pease’s past medical history was “remarkable for anxiety with

depression.”     Dr. Fortson’s notes also show that Pease was diagnosed

with anxiety disorder with depression in 2004. Additionally, Dr. Stutts

was given the records of Dr. Brownell, stating that in April 2004 Pease

had “[s]ituational depression associated with anxiety.”                  Dr. Brownell’s

notes     also   list    medications   prescribed        by   him        that   included

antidepressants.        While Dr. Stutts may not have been apprised of the

reports made by Dr. Eyanson the day before the injury stating that Pease

experienced symptoms of depression, Dr. Stutts received materials to

apprise    him    of    Pease’s   preexisting    level   of   depression        and   the

medications Pease took before the January fall.                          Therefore, the

commissioner may have reasonably relied on the conclusions of

Dr. Stutts in finding Pease’s work injury aggravated her depression.

        In sum, the commissioner’s finding that Pease’s preexisting

depression was aggravated by her accident on January 26, 2005, is

supported by substantial evidence.              The commissioner relied on an

opinion of a psychiatrist who concluded that Pease’s work injury

aggravated her depression. In addition to the medical history provided

by Pease, the psychiatrist’s conclusions were made after receiving several

medical    records      showing    Pease’s    history    with    depression.          The

conclusions      were    consistent    with     the   opinions      of    two    medical

professionals who personally evaluated Pease several times following the

accident. Although another expert offered a contrary opinion, the weight

to be given conflicting expert opinions is within the province of the
                                      21

commissioner. The commissioner’s decision explained why he rejected

the conflicting opinion and was otherwise sufficiently detailed to show

the path the agency took through the conflicting evidence.               See

Terwilliger v. Snap-On Tools Corp., 529 N.W.2d 267, 274 (Iowa 1995);

Catalfo v. Firestone Tire & Rubber Co., 213 N.W.2d 506, 510 (Iowa 1973).

        IV. Remaining Issues.

        On direct appeal, the District raised three additional issues. First,

the District argued the commissioner failed to perform a de novo review

of the deputy commissioner’s proposed decision.        Second, the District

asserted that the commissioner’s decision regarding disability was not

supported by substantial evidence. Third, the District argued that the

district court erred in awarding certain medical benefits following Pease’s

injury. The court of appeals held the commissioner performed a de novo

review as required.      Also, in light of its conclusion that substantial

evidence did not support the commissioner’s findings of medical

causation, the court of appeals did not address the disability argument

and reversed the award of medical expenses. We discuss each issue in

turn.

        A. De Novo Review. We agree with the court of appeals that the

commissioner performed a de novo review of the deputy commissioner’s

findings. The appeal decision states:

        Upon de novo review, it is apparent that the presiding deputy
        relied most heavily on the opinions of Ray Miller, M.D., and
        Raymond Stutts, D.O., Ph.D., to find that claimants pre-
        existing conditions were substantially and permanently
        aggravated as a result of her injury of January 26, 2005.
        Both Dr. Miller and Dr. Stutts provide in-depth and
        substantiated medical opinions that are consistent with
        claimant’s ability to maintain her employment position prior
        to her fall, but no longer able to maintain her employment
        position following her fall.
                                      22

The District argues this passage “reads like substantial evidence review.”

We disagree. The commissioner expressly stated that he was performing

a de novo review.     Also, the commissioner adopted in large part the

deputy commissioner’s proposed decision. Consequently, his discussion

focused on the reasons he adopted the deputy’s findings and offered

“additional analysis” explaining why he found the opinions of Dr. Miller

and Dr. Stutts credible. We therefore conclude the commissioner applied

the appropriate standard of review in its appeal decision.

      B. Extent of Disability. The commissioner, adopting the deputy

commissioner’s findings, concluded Pease suffered a permanent and total

industrial disability. Industrial disability is determined by an evaluation

of the employee’s earning capacity.        IBP, Inc. v. Al-Gharib, 604 N.W.2d

621, 632 (Iowa 2000).        The commissioner may consider a number of

factors   in   determining    industrial    disability,   including   functional

disability, “age, education, qualifications, experience, and [the claimant’s]

inability, because of the injury, to engage in employment for which [s]he

is fitted.” McSpadden v. Big Ben Coal Co., 288 N.W.2d 181, 192 (Iowa

1980) (internal quotation marks omitted).

      In finding permanent and total disability, the deputy commissioner

stated:

             On January 6, 2006 the claimant was discharged by
      the employer because the claimant’s permanent restrictions,
      from her work injury of January 26, 2005, were such that
      the school district determined that “these permanent
      restrictions make you unable to perform the essential
      functions of the position of ‘job coach,’ and unable to
      perform essential functions of any other job in the District in
      your pay range. . . .”

             Due to her physical restrictions, depression and pain
      the claimant is unable to return to any job she has
      previously held.      The Cedar Rapids Community School
      District is a large employer and as such its inability to return
                                      23
        the claimant to work in any position is highly significant and
        indicative of the claimant’s loss of ability to work in the
        competitive labor market. See Bacon v. Ft. Dodge Animal
        Health, File No. 5001168, (App. February 23, 2007)[.]
        Considering the claimant’s medical impairments, daily pain,
        current training, permanent restrictions, inability of the
        employer to find a[n] alternative position for the claimant, as
        well as all other factors of industrial disability, the claimant
        has suffered a 100 percent loss of earnings capacity.

        After a careful review of the evidence, we conclude substantial

evidence supports these findings.         Pease offered direct testimony and

several expert opinions supporting a finding of permanent total disability.

Although, as the District observes, some evidence in the record suggests

Pease    is   capable   of   performing    minimal   physical   activity,   the

commissioner gave more weight to the evidence in support of permanent

total disability and found Pease’s experts more credible. We, therefore,

will not disturb the commissioner’s finding that Pease suffers a

permanent total industrial disability. See Robbennolt v. Snap-On Tools

Corp., 555 N.W.2d 229, 234 (Iowa 1996) (“The court must not reassess

the weight of the evidence because the weight of the evidence remains

within the agency’s exclusive domain.”).

        The District also argues substantial evidence is lacking in the

commissioner’s industrial disability determination because Pease’s work

injury did not prevent her from returning to full-time employment;

rather, Pease’s preexisting, nonwork related disabilities prevented her

from doing so. This argument, however, is an attempt to resurrect the

District’s apportionment claim. In Second Injury Fund of Iowa v. Nelson,

544 N.W.2d 258, 264 (Iowa 1995), we summarized our approach to

apportionment, stating:

        When a prior injury, condition or illness, unrelated to
        employment, independently produces an ascertainable
        portion of an injured employee’s cumulative industrial
                                      24
      disability, the employer is liable only for that portion of the
      industrial disability attributable to the current injury. In
      other words, the industrial disability is apportioned between
      that caused by the work-related injury and that caused by
      the nonwork-related condition or injury. Varied Enterprises,
      Inc. v. Sumner, 353 N.W.2d 407, 411 (Iowa 1984). The
      employer is liable only for the work-related portion.

      The commissioner and the district court both concluded that the

District failed to preserve its apportionment claim. During the hearing

before the deputy commissioner, the deputy discussed with the parties

the issues in dispute. The deputy made no mention of apportionment.

Before proceeding, the deputy asked the District’s attorney whether there

were any issues in dispute that he did not discuss.             The District’s

attorney stated, “I do not believe so.         I do not believe that there are

additional issues that you have not covered.” Further, in his proposed

decision, the deputy did not address the apportionment claim.             The

District failed to file a motion for rehearing or a motion to enlarge the

deputy’s findings.     Under these circumstances, the District failed to

preserve err on its apportionment claim. See Iowa Admin. Code r. 876—

4.28(7) (“An issue will not be considered on appeal if the issue could have

been, but was not, presented to the deputy.”); cf. Freedom Fin. Bank v.

Estate of Boesen, 805 N.W.2d 802, 809 (Iowa 2011) (holding err is not

preserved when the district court does not address an issue and a party

fails to file a motion to enlarge findings).

      C. Medical Expenses. Finally, the District argues Pease failed to

show certain medical bills from Cardiologists PC, East Central Iowa

Acute Care, Famous Footwear, and Dr. Brownell were related to her work

injury. Specifically, the District asserts Pease failed to establish a causal

connection between her work injury and medical expenses she incurred

in July 2006 to address her heart complaints.
                                     25

      We   agree   with   the   district   court   that   the   commissioner’s

determination on the issue is supported by substantial evidence. Pease

testified that she went to the emergency room in 2006 because her “heart

was beating real fast.” She explained that she met with Dr. Brownell and

Dr. Brownell advised her to go to the emergency room. Pease testified

that her heart symptoms were associated with her work injury because

they related to the anxiety she experienced following the accident.

      Pease’s testimony is supported by medical records submitted at the

hearing.   Medical records from July 2006 establish that Pease’s

physicians believed her heart-related symptoms were associated with

Dr. Stutts’ treatment of her depression. A physician who met with Pease

on July 12, 2006, “strongly” recommended she follow up with Dr. Stutts

because he “felt that some of [Pease’s] orthostatic changes may [have

been] due to her multiple medications.”        Similarly, on July 16, 2006,

Pease was evaluated for difficulty breathing and chest discomfort. The

physician’s assessment of Pease stated that Pease suffered “[p]ersistent

waking tachycardia, likely anxiety reaction.” Pease was again advised to

make an appointment with Dr. Stutts, who was treating Pease for what

the commissioner determined were work-related problems.              On these

facts, we decline to disturb the commissioner’s findings.

      The district court did not address the commissioner’s award of

medical bills unrelated to Pease’s heart symptoms. The District did not

file a motion to enlarge or otherwise request the court to address the

issue. Thus, the District did not preserve err on its argument related to

the remaining medical bills.        See Stammeyer v. Div. of Narcotics

Enforcement, 721 N.W.2d 541, 548 (Iowa 2006).
                                   26

      V. Conclusion.

      For the reasons discussed above, we conclude the commissioner’s

findings of fact are supported by substantial evidence. We also conclude

the commissioner performed the appropriate standard of review of the

deputy commissioner’s proposed decision and did not err in assessing

Pease’s heart-related medical bills against the District.   We, therefore,

vacate the decision of the court of appeals and affirm the judgment of the

district court.

      DECISION OF COURT OF APPEALS VACATED; DISTRICT

COURT JUDGMENT AFFIRMED.

      All justices concur except Mansfield, J., who takes no part.
