United States Court of Appeals
                           FOR THE EIGHTH CIRCUIT
                                   ___________

                                   No. 04-1085
                                   ___________

Rebecca A. Lopez,                       *
                                        *
             Appellant,                 *
                                        * Appeal from the United States
      v.                                * District Court for the
                                        * Southern District of Iowa.
Jo Anne B. Barnhart, Commissioner       *
of Social Security Administration,      *      [UNPUBLISHED]
                                        *
             Appellee.                  *
                                   ___________

                             Submitted: June 17, 2004
                                Filed: August 31, 2004
                                 ___________

Before BYE, BOWMAN, and MELLOY, Circuit Judges.
                          ___________

PER CURIAM.

       Rebecca Lopez appeals the decision of the District Court1 affirming the denial
of social security disability benefits. She sought disability insurance benefits based
on degenerative-disc disease, fibromyalgia, narcolepsy, and sleep apnea. We review
a district court's decision upholding the denial of social security benefits de novo,
Lauer v. Apfel, 

, 702 (8th Cir. 2001), but our review of the Social
Security Commissioner's final decision is deferential; we review that decision only

      1
       The Honorable Charles R. Wolle, United States District Judge for the Southern
District of Iowa.
to ensure that it is supported by "substantial evidence in the record as a whole," Estes
v. Barnhart, 

, 724 (8th Cir. 2002). In the District Court and on appeal,
Lopez urges that the ALJ erred by not crediting the opinion of her treating physician,
Dr. Mahadevia, who considered her to be disabled. We agree that the decision of the
ALJ is supported by substantial evidence and affirm.

       In this case, Lopez points to a letter from Dr. Mahadevia attesting to the
substantial limitations her conditions imposed on her and to the doctor's assessment
of her residual functional capacity as supporting her disability claim. Although the
opinion of a treating physician is normally entitled to deference, an ALJ need not
defer to such an opinion when it is not internally consistent or is not supported by
acceptable clinical or diagnostic data. Anderson v. Barnhart, 

, 813 (8th
Cir. 2003) (quoting Cantrell v. Apfel, 

, 1107 (8th Cir. 2000)). The ALJ
determined, and we agree, that Dr. Mahadevia's letter and residual functional capacity
assessment are not internally consistent. The objective medical evidence in the record
strongly suggests that Lopez's condition improved significantly with treatment and
suggests that her daytime sleepiness was well controlled with Ritalin. In short, the
record supports the ALJ's assessment that Lopez could return to her previous
employment. See Patient Notes of Dr. Mahadevia (Sept. 1, 2000) ("She is doing
remarkably well. She is sleeping well, and she feels well rested . . . she is markedly
improved."); Patient Notes of Dr. Mahadevia (Feb. 13, 2001) ("She is doing
remarkably well. She is much more energetic. Her hypersomnolence is markedly
improved except later in the day when she feels much better."); Patient Notes of Dr.
Mahadevia (Mar. 20, 2001) ("She seems to be doing reasonably well. . . . does often
have excessive daytime sleepiness, but with Ritalin she is well controlled."); Patient
Notes of Dr. Mahadevia (Oct. 23, 2001) ("She seems to be progressively
improving . . ."); Patient Notes of Dr. Madaveia (Mar. 22 2002) ("With nasal CPAP
therapy and Ritalin, she is doing remarkably well . . . . her daytime sleepiness is under
control."). Other medical evidence also reinforces the ALJ's conclusion. Dr. Dvorak,
who performed surgery on Lopez to alleviate her sleep apnea reported that Lopez was

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"very pleased she had the surgery. She reports she's breathing much better through
her nose and sleeping much better. She is starting to have dreams again and is
actually losing weight since she's felt so much better." Dr. Dvorak Letter (Feb. 3,
2000). Moreover, even the letter that Lopez points to tends to undermine her
position. In that letter, Dr. Mahadevia notes that "she has been doing reasonably
well" and, with regards to her excessive daytime sleepiness, "she has done clinically
reasonably well with Ritalin." Letter of Dr. Mahadevia (Dec. 10, 2002). While Dr.
Mahadevia noted that Lopez "will continue to have off and on episodes of fatigue,
excessive daytime sleepiness, and cataplexy," 

does not entirely
square with his own patient notes and with the other objective medical evidence.
Accordingly, the District Court did not err when it determined that the ALJ's decision
was supported by substantial evidence.

      The judgment of the District Court is affirmed. See 8th Cir. R. 47B.
                     ______________________________




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