Key Lessons from Mattison v. Astrue
- Nov 17, 2025
- 4 min read
When it comes to children applying for SSI (Supplemental Security Income) benefits, the Social Security Administration’s (SSA) Listing of Impairments (20 C.F.R. Pt. 404, Subpt. P, Appx. 1) is often the first and most critical checkpoint. But what happens when a child’s condition doesn’t neatly meet those listing criteria? The 2013 Ninth Circuit case Mattison ex rel. K.A. v. Astrue offers important lessons on how SSA evaluates childhood disability — and how attorneys should approach such claims.
Case Background: K.A.’s Childhood SSI Claim
Who was involved: K.A., a minor with severe asthma, applied for SSI benefits.
What the ALJ decided: The Administrative Law Judge found that K.A.’s asthma did not meet Listing 103.03 (the SSA’s asthma listing), despite reports of frequent exacerbations and dependence on medication.
Alternative test used: Because K.A. did not meet the listing, the ALJ turned to the functional equivalence test under 20 C.F.R. § 416.926a. This test evaluates how impairments affect a child’s daily functioning across six domains.
Understanding the SSA’s Functional Domains
Under 20 C.F.R. § 416.926a, SSA examines how a child’s condition impacts six key areas of functioning:
Acquiring and using information
Attending and completing tasks
Interacting and relating with others
Moving about and manipulating objects
Caring for oneself
Health and physical well-being
For a child to be considered disabled under the functional equivalence standard, they must show either:
A marked limitation in two of these domains, or
An extreme limitation in one domain.
In K.A.’s case, the ALJ found a marked limitation only in the health and physical well-being domain — but not in any of the others.
Key Legal Insights from the Court’s Decision
Here are some of the most important take-aways and legal lessons from Mattison ex rel. K.A. v. Astrue:
Medication control matters
K.A.’s FEV₁ values (a critical lung function measure for asthma) were above the required listing threshold when she was on medication.
The court emphasized that impairments “effectively controlled by medication are not disabling.” This principle echoes prior case law (e.g., Warre v. Commissioner of Social Security).
Record-gathering must be thorough — but there are limits
The claimant argued that the ALJ should have obtained more medical evidence.
The court disagreed, saying that even the additional records would not have shown a disabling impairment lasting a continuous 12-month period, which is required under SSA’s rules. (See 20 C.F.R. §§ 404.1509, 416.909.)
Interpreting functional domains correctly
The ALJ acknowledged K.A.’s difficulty with physical exertion, but there was no evidence of problems with gross or fine motor skills.
The court reasoned that limitations from a respiratory condition like asthma primarily fall within the “health and physical well-being” domain — not in multiple domains.
Weight of third-party statements
A school health aide described K.A.’s asthma as debilitating.
Still, because school records indicated that K.A. was functioning well in most situations, the court found that even if the ALJ should have given more weight to the aide’s statements, any error was “harmless” — it would not have changed the outcome. (See Molina v. Astrue for a similar principle.)
Why This Case Matters for Disability Law Practice
Beyond Diagnosis: Focus on Functional Limitations
As attorneys, we can’t rely solely on a medical diagnosis or lab values. We must build a strong functional case: how the child’s impairment affects daily life across SSA’s six domains.
Medication & Management Are Key
Demonstrating that a condition is not disabling when controlled by treatment can be fatal to a claim under SSA’s rules. But that doesn’t mean we ignore these cases — rather, we need to show residual functional impact despite treatment, or argue how “controlled” isn’t fully effective in real life.
Thorough Record Development
It’s crucial to gather school records, doctors’ notes, third-party observations, and more. But we should also evaluate whether additional evidence is likely to change the outcome, especially in light of SSA’s 12-month durational requirement.
Strategic Use of Third-Party Testimony
Statements from teachers, school health aides, or family members can be powerful — but they must tie into functional deficits in relevant domains. We need to frame these statements in the language of SSA’s regulations.
Appeal Planning
As with many SSA denials, the ALJ’s decision may be legally defensible but still appealable. We should assess for possible legal errors (e.g., misinterpretation of functional domains, failure to develop the record, or misweighing of testimony) to lay groundwork for reconsideration or court review.
Conclusion & Take-Home Message
The Mattison ex rel. K.A. case is a powerful reminder: SSA’s listing criteria are strict, but meeting them is not the only path to a successful children’s disability claim. Functional equivalence — how an impairment actually limits a child’s daily life — can make or break a case.
For attorneys working on childhood SSI claims:
Build a holistic case that goes beyond medical tests.
Draw out functional limitations in all relevant domains.
Use third-party statements strategically and in regulatory terms.
Be prepared to challenge decisions that hinge solely on “controlled” conditions.
If you’re navigating a child disability case, especially where the listing doesn’t neatly apply, it’s essential to partner with counsel who understands both the medical and legal landscape. At Tower Law Group, we specialize in Social Security Disability cases — including those involving children — and can help you assemble the right evidence, frame your arguments, and advocate effectively.
Got any questions? Schedule a consultation with us. I’m here to help. It’s a lot to take in, but we’ll get through it together. After all, navigating these waters is always easier when you’ve got someone to chat with.
