A chiari malformation (CM) is a defect in the structure of the brain or spinal cord. Because of the abnormal structure of the skull or spinal cord, the cerebellum and brain stem can be compressed, which results in a decreased flow of the fluid that protects the spine and the brain. Symptoms include dizziness, muscle weakness, numbness, vision problems, headaches, and difficulty with balance and coordination.
CM is divided in to four categories: Types I, II, III, and IV. Type IV CM is the most serious. Type II CM used to be referred to as Arnold-Chiari malformation (after the researchers who first described the condition).
Medication may lessen the symptoms of CM, but the only way to correct the physical structure of the brain is through surgery.
Although a diagnosis of CM alone will not automatically qualify you for disability, you could win your claim if your symptoms are severely limiting. At the initial stage of the disability determination, the Social Security Administration (SSA) must determine whether your CM match the requirements of a disability listing. One listing that addresses some cases of CM is listing 11.08, for spinal cord disorders. You could meet this listing if you have either:
If your limitations are more moderate than what the listing calls for, Social Security will look at how your limitations affect your ability to work. If the SSA feels you can no longer perform your most recent jobs, it will determine whether there are any other jobs you can do (or learn to do). To do this, the SSA will prepare a "residual functional capacity" assessment (RFC) that details your ability to perform certain job related tasks in light of your symptoms. An RFC is created based on the medical records you have provided to the SSA, and any examinations performed by an SSA doctor (called consultative examinations.)
For example, more severe forms of CM can result in significant impairments to a person’s balance and coordination. This deficit would eliminate any positions that required the use of heavy machinery or dangerous equipment such as construction work. CM can also affect the use of a person’s hands and fingers to the extent that fine motor skills are impaired. Fine motor skills are necessary for activities like typing, filing papers, or assembling, examining, and sorting objects on an assembly line, so the inability to perform these tasks would eliminate most secretarial and factory positions. CM may also cause significant numbness and tingling in the hands that limit the ability to lift, carry, push, or pull even light objects. This limitation alone could prevent most work.
CM sufferers may also experience difficulty with vision and speech, making it difficult to perform even day-to-day tasks or jobs that require good vision or hearing, depending on the severity of the vision or hearing loss.
You should also ask your treating physician to fill out an RFC form for you. Although the SSA will accept RFCs from any doctor, it gives more weight to reports that are prepared by a physician who specializes in the diagnosis and treatment of CM. You must also include objective medical evidence like CT scans, MRIs, and your doctor’s reports to support your doctor’s opinion.
Before the SSA will assess your claim, you must meet the basic requirements for disability: you may not earn more than about $1,200 a month from work, and your CM must prevent you from working for at least a year (or be expected to do so).
In addition, to qualify for SSDI, you must have a significant work history with employers that paid taxes to the SSA. For more information, see our section on SSDI eligibility.
SSI is available to people who don’t have a qualifying work history and who meet the SSA’s limit on income and assets. For more information, see our section on SSI eligibility.