Your toddler isn't talking yet, and the pediatrician has referred you to early intervention. When the service coordinator calls, their first question isn't about words at all. They want to know when your child's hearing was last tested.

I've spent my career building learning plans for young children, and every one of those plans rests on the same assumption: the child can take in what we're showing and telling them. A toddler who hears speech as if through a closed door isn't ignoring you. A baby who can't make out a face across the room isn't withdrawn. Before anyone teaches a skill, someone has to confirm what's reaching the child in the first place. That's the job of sensory screening, and it's why vision and hearing sit at the front of the early intervention line.

Why Screening Comes Before Therapy

Speech and language grow from thousands of small listening moments: overheard conversations, sung lullabies, your voice narrating breakfast. A child with even a mild hearing loss misses a portion of every one of those moments, and the gap compounds month after month. Roughly one to three of every 1,000 newborns has a permanent hearing loss, which is why every state screens hearing before babies leave the hospital. The national benchmark is called 1-3-6: screening by one month of age, a full diagnostic evaluation by three months, and enrollment in early intervention by six months.

Vision works the same way. Babies reach because they see something worth reaching for. They learn faces, cause and effect, and shared attention by looking. When a young child's motor or social development stalls, an undetected vision difference is one of the first possibilities a thorough team rules out, because months of therapy aimed at the wrong target is time a developing brain doesn't get back.

If your child didn't pass a newborn hearing screening and you were told to wait and see, don't. Follow-up diagnostic testing is the step families most often lose in the shuffle, and the 1-3-6 timeline exists because the earlier a hearing difference is identified, the closer a child's language development tracks with hearing peers.

Vision and Hearing Under Part C Eligibility

Part C of IDEA, the federal law behind birth-to-three early intervention, covers children in two ways: through a measured developmental delay, or through a diagnosed condition that carries a high probability of delay. In most states, permanent hearing loss and visual impairment sit on that second list as established conditions. A diagnosis alone qualifies your child. You don't have to wait for a delay to show up on a test, and you don't need a doctor's referral to start; any parent can request an early intervention evaluation by calling their state program directly, and the evaluation is free in every state.

If you're unsure whether what you're noticing rises to the level of a call, the early warning signs families most often see are a reasonable starting checklist. Once your child is found eligible, the team writes an Individualized Family Service Plan, the IFSP, which names each service your child will receive, how often, and who provides it. For a child with a hearing or vision difference, who provides it is the part to watch.

What Makes Sensory Services Different from Speech, OT, and PT

Most families know early intervention through its big three: speech, occupational, and physical therapy, the disciplines that build skills. Sensory services solve a different problem: access. A teacher of the deaf and hard of hearing, often called a TOD, works on how language reaches your child, whether through hearing aids or cochlear implants, through visual language like ASL, or through a combination. If your family is weighing those paths, a TOD walks you through the communication options without pushing you toward one. A teacher of students with visual impairments, a TVI, adapts materials, lighting, and routines so a child with low vision can use the sight they have. An orientation and mobility specialist teaches a child with a visual impairment to move through the world safely and on purpose.

The distinction matters at the IFSP table. A speech therapist can work on words; a TOD makes sure words are reaching your child in the first place. Both may belong on the team, and for a child with a diagnosed sensory difference, the specialist isn't an optional extra. Vision services, audiology, and orientation and mobility appear by name in the federal regulations that define early intervention services.

At this age, sensory services usually happen in your home and run on a coaching model. A TVI won't drill your baby with flashcards; they'll show you how to position a bottle, a toy, or your own face where your child can find it, then build those adjustments into feeding, play, and bedtime. The goal is a daily environment your child can read, not a weekly session your child attends.

When Your Program Says It Has No Specialist

Early intervention programs are staffed unevenly, and in some regions a TOD or TVI is genuinely scarce. Scarce isn't the same as unavailable, and this is where your persistence changes the outcome.

• Ask your service coordinator directly who on the team is qualified to work with a child with hearing loss or low vision. If the answer is no one, ask how the program contracts for that expertise. Part C requires services to be delivered by qualified personnel, so "we don't have anyone" is the start of a conversation, not the end of one.
• Get the service written into the IFSP anyway. Services are listed based on your child's needs, not the program's current staffing. A service on the IFSP creates an obligation; a service left off creates nothing.
• Call your state school for the deaf or the blind. Most run outreach programs that consult with local early intervention teams at no cost to families, and some provide direct home visits.
• Find the parent networks. Hands & Voices, a parent-driven organization for families of deaf and hard of hearing children, keeps chapter lists by state, and the American Printing House's FamilyConnect community does similar work for families of children with visual impairments.

If your child has a diagnosed hearing or vision difference, or a screening result no one followed up on, your next step is specific: ask your service coordinator, in writing, whether a sensory specialist has evaluated your child and when one will. Every learning plan I've ever helped a family build started with the same confirmation: that the world is reaching their child. Once you know it is, everything else you teach has somewhere to land.