Sheila J. Young appeals from the district court’s 2 order affirming the denial of her request for disability insurance benefits under Title II of the Social Security Act, 42 U.S.C. § 401 et seq. We affirm.
I.
Young was born on September 17, 1958. Her past relevant work is that of a general duty nurse. Young filed for disability insurance benefits in October of 1994, alleging'that she could not work because of multiple sclerosis.
3
After her request was denied initially and upon review, Young appealed to an administrative law judge (ALJ), who evaluated her claim aсcording to the five-step sequential analysis prescribed by the social security regulations.
See
20 C.F.R. §§ 404.1520(a)-(f);
Bowen v. Yuckert,
The Appeals Cоuncil denied Young’s request for further review, making the ALJ’s decision the final decision of the Commissioner. Young then sought review in the district court pursuant to 42 U.S.C. § 405(g). The district court granted the Commissioner’s motion for summary judgment, finding that substantial evidenсe supported the Commissioner’s decision to deny Young disability benefits. For reversal, Young challenges the ALJ’s credibility findings, RFC assessment, formulation of the hypothetical, and conclusions regarding the availability of jobs in the nаtional economy that Young could perform.
II.
Our role on review is to determine whether the Commissioner’s findings are supported by substantial evidence on the record as a whole.
See Prosch v. Apfel,
Young first argues that the ALJ failed to make credibility determinations regarding the testimony of Young and her husband and improperly discounted various statements by Young’s friends solely because they did not constitute medical evidence. We find, however, that although the ALJ did not expressly discredit Young’s testimony, he did so implicitly by evaluating her testimony in light of the factors set forth in
Polaski v. Heckler,
Second, Young contends that the Commissioner did not establish by medical evidence that Young possessed the RFC to work full-time in a competitive environment.
5
We disagree. The ALJ’s opinion thoroughly discussed Young’s medical treatment records from the relevant period before assessing her physical abilities. After desсribing Young’s limitations, the ALJ noted medical reports showing that her neurological status was essentially normal and that her May 1988 magnetic resonance imaging test demonstrated no evidence of multiple sclerosis. We find it signifiсant that no physician who examined Young submitted a medical conclusion that she is disabled and unable to perform any type of work.
See Brown v. Chater,
Young’s third argument is that the hypothetical posed to the vocational expert did not adequately describe her impairments during the relevant period. Our review of the record, however, leads us to conclude that the hypothetical was supported by substantial evidence. Young contends that the ALJ failed to include limitations related to her bladder control problems and fatigue, but a hypothetical need only include impairments that are supported by the record and which the ALJ acсepts as valid.
See Prosch,
We recognize that incontinence can in some circumstances be a serious disabling condition.
See Crowley v. Apfel,
Last, Young argues that the vocational expert (VE) contradicted himself by suggesting that Young was limited to sedentary work but then stating that she could perform several light nursing jobs. 6 The VE acknowledged that several of the jobs he recommended are classified in the Dictionary of Occupational Titles (DOT) as light jobs. However, he indicated that some of these positions as they exist in the national economy and locally сould be performed at a sedentary level depending on the equipment and office setup.
Although the DOT generally controls, “[t]he DOT classifications may be rebutted ... with VE testimony which shows that ‘particular jobs, whether classified as fight or sedentary, may be ones that a claimant can perform.’ ”
Montgomery v. Chater,
The judgment is affirmed.
Notes
. The Honorable Charles R. Wolle, Chief Judge, United States District Court for the Southern District of Iowa.
. Multiple sclerosis is an autoimmune disorder in which the insulating sheath surrounding nerve fibers is destroyed and replaced by scar tissue, causing nerve communication to be disrupted. Symptoms, which vary widely from person to person and from stage to stage of the disease, include muscle weakness, numbness, fatigue, loss of balance, pain, and loss of bowel and bladder cоntrol. Most often the disease remits and relapses, but it may progress without remissions or with periodic plateaus or minimal improvements. No single test confirms a diagnosis, but magnetic resonance imaging can reveаl the areas of scar tissue. See Sloane-Dorland Annotated Medical-Legal Dictionary 632-33 (1987), supp. at 470-71 (1992).
.For insured status (the Act’s "earnings requirement”), an individual must have 20 quarters of coverage in the 40-quarter period ending with the first quarter of disability. See 42 U.S.C. §§ 416(i)(3)(B), 423(c)(1)(B).
. The parties engage in a lengthy dispute over whether RFC is properly evaluated at step four or step five, and over who bears the burden of demonstrating RFC. We reiterate that RFC is determined at step four, where the burden of proof rests with the claimant.
See
20 C.F.R. §§ 404.1520(a),(e),(f); 404.1545-46; 404.1560-61;
Bowen,
. Light work requires the ability to lift up to 20 pounds at a time, whereas sedentary work requires the ability to lift only 10 pounds. See 20 C.F.R. § 404.1567(a) & (b).
