Listing 11.09 in 2026: How Social Security Decides Multiple Sclerosis Disability Claims Under 11.09A and 11.09B, Why the Two Paths Demand Completely Different Evidence, and the Documentation That Wins at Step 3

By Anthony Albert, Benefits Research Director · Published June 17, 2026 · 13 min read

Multiple sclerosis is one of the most denied disability claims at Social Security. People file with a confirmed MS diagnosis, an MRI showing demyelinating lesions, and a neurology note describing fatigue. That file usually gets denied because Listing 11.09 is not about the diagnosis. It is about specific functional impairment in either the motor system or in the combination of physical and cognitive function.

If you want to win at Step 3 on multiple sclerosis, you have to know which of the two subparts your case fits, what evidence each one demands, and how the neurology record has to be phrased so SSA can match it to the listing. This is the 2026 walkthrough.

What Listing 11.09 actually says

Listing 11.09 sits inside section 11.00 of the Blue Book, the neurological system. The current version reads:

11.09 Multiple sclerosis, characterized by A or B:

1. A. Disorganization of motor function in two extremities (see 11.00D1), resulting in an extreme limitation (see 11.00D2) in the ability to stand up from a seated position, balance while standing or walking, or use the upper extremities; or
2. B. Marked limitation (see 11.00G2) in physical functioning (see 11.00G3a), and in one of the following:
   • Understanding, remembering, or applying information (see 11.00G3b(i)); or
   • Interacting with others (see 11.00G3b(ii)); or
   • Concentrating, persisting, or maintaining pace (see 11.00G3b(iii)); or
   • Adapting or managing oneself (see 11.00G3b(iv)).

Two paths. Completely different evidence requirements. Most files try to argue both and end up arguing neither well. Pick the path that fits your case, then build the evidence for that path.

The diagnostic foundation

Before you touch the listing criteria, you need a confirmed MS diagnosis in the file. SSA expects diagnosis under current neurology standards, which means the McDonald criteria, most recently updated in 2024. The McDonald criteria require evidence of:

• Two or more clinical attacks with objective clinical evidence of two or more lesions, or
• Two or more clinical attacks with objective clinical evidence of one lesion and clear-cut historical evidence of a previous attack involving a different anatomical site, or
• One clinical attack with objective evidence of two or more lesions plus dissemination in time demonstrated by MRI or by detection of CSF-specific oligoclonal bands, or
• One clinical attack with objective evidence of one lesion and dissemination in both space and time demonstrated by additional MRI lesions or CSF findings, or
• Primary progressive MS: one year of disability progression independent of clinical relapses plus two of the following: one or more T2-hyperintense lesions characteristic of MS in periventricular, juxtacortical or cortical, or infratentorial regions; two or more T2-hyperintense lesions in the spinal cord; presence of CSF-specific oligoclonal bands.

The file should contain MRI brain reports, MRI cervical and thoracic spine reports as appropriate, the neurology consult note diagnosing MS under the McDonald criteria, and if available, the lumbar puncture report showing oligoclonal bands. If your file is missing any of those, your neurologist may need to write a summary letter making the diagnostic case explicit.

11.09A: extreme limitation in motor function

11.09A is the cleaner path on paper because it does not require any cognitive evidence. It requires disorganization of motor function in two extremities resulting in an extreme limitation in one of three areas:

• Ability to stand up from a seated position
• Ability to balance while standing or walking
• Ability to use the upper extremities

"Disorganization of motor function" is defined in 11.00D1 as interference with movement of two extremities by paresis or paralysis, tremor, abnormal involuntary movements, ataxia, or sensory disturbance. Two extremities means either two arms, two legs, or one arm and one leg.

"Extreme limitation" under 11.00D2 means the inability to stand up from a seated position, maintain balance in a standing position and while walking, or use the upper extremities to independently initiate, sustain, and complete work-related activities involving fine and gross movements. The Blue Book is specific that extreme limitation is more severe than marked. It does not mean total inability in every case, but it means functioning that is far below what an unimpaired person could do.

The clinical findings that build an 11.09A file include:

• Documented spasticity, weakness, or sensory loss on neurology exam
• Pyramidal tract signs (hyperreflexia, Babinski sign, clonus)
• Cerebellar signs (dysmetria, intention tremor, ataxia, gait instability)
• Sensory ataxia with Romberg positive
• Spinal cord syndromes documented on cord MRI with corresponding clinical deficit
• EDSS (Expanded Disability Status Scale) score, typically 6.0 or higher
• Physical therapy or occupational therapy evaluations
• Assistive device prescriptions (walker, bilateral canes, wheelchair)

The EDSS score is the most important single piece of evidence in many MS cases. An EDSS of 6.0 means the patient requires intermittent or unilateral constant assistance (cane, crutch, brace) to walk about 100 meters with or without resting. EDSS 6.5 means bilateral assistance to walk about 20 meters without resting. EDSS 7.0 means essentially restricted to wheelchair, transferring alone, but able to be up in wheelchair about 12 hours per day. EDSS 7.5 means unable to take more than a few steps, requires wheelchair, may need aid in transferring.

An EDSS of 6.0 or higher generally maps to 11.09A territory, though the listing does not require a specific score. The neurology record has to describe the actual motor deficits and the actual functional limits.

11.09B: marked limitation in physical functioning plus mental functioning

11.09B is the path most MS claimants actually fit. It requires marked limitation in physical functioning AND marked limitation in one of four mental functioning areas. Both prongs have to be present.

"Marked limitation" under 11.00G2 means the impairment seriously interferes with the ability to independently initiate, sustain, and complete activities. The level is more than moderate but less than extreme. It is the second-highest rating SSA uses.

"Physical functioning" under 11.00G3a covers persistent or intermittent symptoms that affect the ability to independently initiate, sustain, and complete work-related activities, including:

• Standing up from a seated position
• Balancing while standing or walking
• Using upper extremities
• Independently initiating, sustaining, and completing work-related activities including fine and gross movements

This is a broader test than 11.09A. You do not need extreme limitation. You need marked limitation, which is a notch below.

The four mental functioning areas under 11.00G3b are pulled from the paragraph B mental criteria. SSA uses the same terminology and the same definitions across listings 11.00, 12.00, and the related listings.

MS-related cognitive impairment is well documented in the neurology literature. The Symbol Digit Modalities Test (SDMT) is the most sensitive screening tool. A drop of 4 points or more from baseline, or a score 1.5 standard deviations below the normative mean, is considered clinically significant cognitive impairment in MS.

The Brief International Cognitive Assessment for MS (BICAMS) is the standard cognitive battery in MS care. If your neurologist has not done a BICAMS or referred for neuropsych testing, that is often the missing piece in an 11.09B file. Push for it.

How fatigue fits in

MS fatigue is the most common symptom in the disease, with most patients reporting it as among the worst. SSA does not list fatigue as a separate criterion under 11.09, but fatigue feeds into both 11.09A and 11.09B through its functional consequences.

Under 11.09A, MS fatigue can produce gait instability and weakness that look like motor disorganization. Documented worsening of motor function after activity is consistent with the section 11.00D2 description of impairment that varies in severity.

Under 11.09B, MS fatigue feeds the physical functioning prong (cannot sustain physical activity through a workday) and the mental functioning prong (cannot sustain concentration, makes more errors as the day goes on). The Fatigue Severity Scale (FSS) and the Modified Fatigue Impact Scale (MFIS) are validated MS fatigue tools. Scores above the impairment threshold (FSS above 36, MFIS above 38) support listing-level severity.

If your file is silent on fatigue measurement, that is a fixable gap. Ask the neurologist to score the FSS or MFIS at your next visit and document the result.

How exacerbations are evaluated

The current listing eliminates the old language about exacerbations and remissions. The new approach: SSA evaluates your functional status during a representative period, which can include both relapse and remission. If your disease has frequent relapses with incomplete recovery, the file should document each relapse, the residual deficit, and the gradual accumulation of disability.

Section 11.00C of the Blue Book is the durational guidance for neurological disorders. SSA needs to evaluate function over a period long enough to assess what your "usual" status is. For MS, that period generally requires three months of evidence after a major exacerbation or treatment change to show whether the deficit is durable.

Disease-modifying therapies (DMTs) like ocrelizumab, ofatumumab, natalizumab, fingolimod, dimethyl fumarate, teriflunomide, and the interferons all reduce relapse rate. A claimant on aggressive DMT who still has progression has a stronger Step 3 case than a claimant on first-line interferon with stable disease.

The disease courses and how SSA reads them

MS has four recognized clinical courses. SSA evaluates each one under 11.09 but the natural history matters.

• Relapsing-remitting MS (RRMS): The most common form, with discrete attacks followed by partial or full recovery. SSA looks at the cumulative disability between attacks and the residual deficits.
• Secondary progressive MS (SPMS): Initially RRMS that has converted to a steadily worsening course. SPMS files generally meet 11.09 more easily because the disability is steadily increasing.
• Primary progressive MS (PPMS): Steady accumulation of disability from the onset without distinct relapses. PPMS often produces 11.09A motor impairment more rapidly than RRMS.
• Progressive-relapsing MS (PRMS): Steadily worsening course with occasional acute exacerbations. The most severe natural history.

Your neurologist should state which course you have in the consult note. If the file just says "MS" without specifying the course, SSA may underweight the severity.

Common reasons 11.09 claims fail

1. File has the diagnosis but not the functional documentation. Neurology notes describe lesions on MRI and confirm McDonald criteria but do not address motor or cognitive function in detail.
2. No EDSS score in the chart. SSA wants to see how impaired the patient is on a recognized MS scale. Without one, the adjudicator is guessing.
3. 11.09B claim with no neuropsych testing. The file argues marked cognitive limitation but has no objective testing to support it.
4. Confusing 11.09A with 11.09B. Filing under 11.09A when the case is really 11.09B (or vice versa) leads to denial because the wrong evidence is in the file.
5. Treatment compliance gaps. SSA expects you to be on appropriate DMT unless there is a documented reason not to be (allergy, JCV positivity for natalizumab, financial cost shelter under POMS DI 24515.012).

Worked Step 3 example

The RFC fight when 11.09 does not fit

Some MS claims do not meet 11.09. They win at Steps 4 or 5 on residual functional capacity. The RFC factors that decide MS cases:

• Standing and walking tolerance (often limited to 2 to 4 hours in an 8-hour day, less in heat)
• Sitting tolerance (some MS patients tolerate sitting well, others develop spasticity and pain)
• Lifting and carrying (often limited to 10 to 20 pounds occasionally)
• Reaching, handling, and fingering (upper extremity weakness, intention tremor, sensory loss)
• Environmental limitations (avoid heat exposure, which provokes Uhthoff's phenomenon)
• Off-task time and absences (fatigue, cognitive fog, frequent neurology appointments, infusion days for natalizumab or ocrelizumab)
• Mental limitations (sustained concentration, complex task tolerance, stress tolerance)

The combination of sedentary exertional limits with environmental restrictions on heat and frequent absences for infusion therapy creates a strong RFC argument. SSR 96-9p describes how multiple non-exertional limitations erode the unskilled sedentary base. Documented heat sensitivity plus a four-week infusion cycle plus cognitive limits often erode the base completely.

How to apply this listing to your case

1. Confirm the diagnosis. The file needs MRI reports, the neurology note diagnosing MS under McDonald 2024 criteria, and the CSF report if available.
2. Get an EDSS score in the chart. Ask your neurologist to score it at every visit so the trend is documented.
3. Identify the subpart. Extreme motor limitation in two extremities goes to 11.09A. Marked physical plus marked mental goes to 11.09B.
4. For 11.09A, document the specific motor deficits, the assistive device prescription, and the physical therapy evaluation.
5. For 11.09B, get neuropsych testing or at least a SDMT and BICAMS in the neurology record. Without cognitive testing, the mental functioning prong is hard to prove.
6. Document fatigue with FSS or MFIS scores. MS fatigue is often the difference between marked and moderate.
7. Build the treatment record. List every DMT tried, the duration, the response, and any reason for discontinuation. Document compliance and the source of any treatment gaps.
8. Get a treating neurologist medical source statement that uses the SSA "marked" and "extreme" terminology explicitly for the relevant functional areas.

Bottom line

Listing 11.09 is winnable but only on a complete file. The two subparts are not redundant. 11.09A is for the patient with severe motor impairment. 11.09B is for the patient with combined physical and cognitive impairment. Your medical evidence has to match one of them. Files that try to argue both, or that have the diagnosis without the functional documentation, lose at Step 3 even when the disease is real and severe.

If you have multiple sclerosis and you are filing or appealing, See If You Qualify and we will audit your file against the 11.09 criteria before SSA does.

Related reading

• Medical equivalence under 20 CFR 404.1526
• SSR 16-3p subjective symptom evaluation
• SSR 96-8p RFC assessment
• Listing 1.20 amputation criteria
• Disability resources in Florida
• Disability resources in New York

Frequently asked questions