The Social Security Act defines disability in all Title II claims and in adult Title XVI claims as the inability to engage in any substantial gainful activity by reason of any medically determinable physical or mental impairment(s) which can be expected to result in death, or which has lasted or can be expected to last for a continuous period of not less than 12 months. “Inability to engage in any substantial gainful activity” means that a claimant’s impairment(s) must not only prevent him or her from performing previous work but from making an adjustment to any other kind of substantial gainful work that exists in significant numbers in the national economy, considering his or her age, education, and previous work experience. The Social Security Administration’s (SSA) regulations provide a series of general and specific narrative guidelines for considering the effects of age, education, and work experience in determining whether an individual can make an adjustment to other work