Lizzie climbed up the playground stairs on all fours, walked across the small suspension bridge and slid down the big red slide at our neighborhood park. I followed just inches behind my 4-year-old daughter ready to catch her.

I had become her shadow by necessity. Her actions were often unpredictable and sometimes dangerous so my arms became her safety net. Her big brown eyes and unruly curly brown hair encapsulated her carefree spirit, and I adored her with a love I never thought myself capable of.

She walked over to the swings and stood there, stiff, her eyes glazed over. She didn’t look to me for help. She didn’t point, raise her arms up or ask me to place her in the swing. But I knew what she wanted—I sensed it.

“Do you want to swing, Lizzie?” I asked in a gentle voice. She remained silent.

I didn’t expect an answer, but I always asked in hopes today was the day she would choose to use her voice to form a word for the sake of communicating with me. I placed her in the swing anyway and pushed her to the exact height I knew she preferred.

A look of contentment came across her face and a giant smile curled her lips. She was in her happy place. This place was a place I wasn’t allowed in—not yet anyway. She lived in an alternative universe inside her head, and after the park, we would spend the rest of the day inside using therapy techniques to pull her from this place into the real world. I missed my daughter and the connection we once had.

There were so many quirks I thought were hers alone, when in fact they were symptoms of autism spectrum disorder.

Here are five possible signs of autism parents should know about. If you notice something that concerns you, please reach out to your pediatrician.

1. Change in language

As a baby, Lizzie’s language gradually changed from babbling to gibberish. “With typically developing language skills, infants will babble often as early as two to three months indicating first instances of intentional and social communication,” says licensed clinical speech language pathologist Julie Liberman. “An early sign of autism may be seen in infants creating nonsense syllables without added social-communicative behaviors.”

Lizzie lost her social-communicative sounds and began to mimic noises from her environment such as screeching sounds or sirens. She also developed a few sounds such as “diddle diddle” that she would repeat all day long. The transition was subtle and slow—enough that at first I didn’t recognize that it was happening. .

2. Sensory processing issues

“Sensory processing is how our brain and body organize and respond to sensory information. Issues develop when we are over or under-responsive to sensory information which impacts the body’s ability to organize it, or modulate it and so responses range outside of typical parameters and dysregulation is observed,” writes licensed occupational therapist Rachel Wolverton.

Lizzie walked on her tiptoes, flapped her arms when she was excited and ran full speed into the couch cushions over and over again. Many toddlers do similar behaviors, and we thought she was just being quirky and adorable. As part of her diagnosis, though, we came to understand that these repeated behaviors were signals that her processing was under-stimulated. She needed these movements to help her body and brain function. This also works the opposite way, too. Many kids are over-sensitive to lights, sounds and/or touch, so they become easily overstimulated. They might cover their ears, melt down when clothes are put on their bodies or withdraw from crowds.

3. Lack of response to name

Lizzie displayed what I call “selective hearing.” I would stand in front of her, saying her name with a raised voice and she wouldn’t respond or look up. She appeared to be deaf, but as soon as the theme song from her favorite Dora the Explorer TV show came on, she would run from the other room to watch.

As autistic teen advocate Matteo Musso explains, “Because we hear your voice so much, we don’t usually respond to our name. It’s that you say our name the same way all the time. A TV is more auditorily complex. One-word, same voice, can get lost in our thoughts and in our brain.”

4. Repetitive behavior

My daughter began lining up her toys by color and her green peas at the dinner table. We thought she was brilliant! She is brilliant, but as it turns out, not because of her repetitive behavior.

While many children love repetition—as any parent who’s got their child’s favorite bedtime story memorized knows—what I learned is that the kind of repetitive behavior we saw in Lizzie is one of the core symptoms of autism.

“Individuals with autism typically find much comfort in repetitive behaviors, giving them a sense of control over their environment in a quite unruly world,” says Dr. Caroline W. Ford, clinical psychologist and director of the Fairhill School and Diagnostic Assessment Center in Dallas. As she explains, autistic children experience real difficulty when their repetitive behaviors are interrupted: “When asked to change or alter the repetitive behavior, many autistic children become overly anxious.”

5. Loss of connection

One of the most beautiful moments between mother and child is the first time her baby looks into her mom’s eyes. It was in that moment with Lizzie, the connection formed was so strong I knew I would be willing to do anything for her.

Slowly over the course of months, she became more and more distant. She wandered around the house aimlessly and didn’t seem to need me at all. As long as there was food and drink available, she was content to be all alone. It was hard to measure because it was a feeling, a distancing, a loss of connection. I second-guessed my feelings regularly. Mothers have a built-in intuition with their children, which should never be underestimated.

After my daughter’s diagnosis with autism at the age of two, we researched and implemented a 30-hours-a-week home therapy program (although it’s important to know that early intervention supports can also be found through community organizations and school systems—you don’t have to do this alone). Now, I’m happy to say, Lizzie has made good progress, and I’ve found (and offered) support in the generous community of parents of autistic children like mine. I even started a non-profit, United in Autism, which partners with local charities to bring community-building, emotional-support events to special needs moms all over the country.

My daughter continues to be a source of joy and amazement. Most importantly, I know now that my daughter and I are not alone—and we never were.