• Tim Walz has shared details about his son Gus, 17, who has been diagnosed with ADHD, anxiety and nonverbal learning disorder
• The disorder impacts the way nonverbal communication — like tone and body language — is processed; it doesn’t mean that those with nonverbal learning disorder can’t speak
• The disorder can be a challenge to diagnose because the symptoms are often similar to other childhood disorders

Democratic vice presidential nominee Tim Walz has shared that his son Gus, 17, has ADHD, anxiety, and nonverbal learning disorder — a diagnosis that Walz calls his son’s “secret power.”

Because the term is nonverbal learning disorder, “people think it means that you’re not speaking,” says Dr. Vera Feuer, a child and adolescent psychiatrist and associate vice president of school mental health at Northwell Health.

“That couldn’t be further away from the truth,” Feuer tells PEOPLE.

According to Feuer, there are two main groups of learning disabilities: verbal and nonverbal.

“These terms refer to the kind of skills that are expected. Verbal skills are reading, writing — and verbal learning disabilities affect how people are able to read, write, and interpret information,” she says, citing dyslexia as an example.

These disabilities, she tells PEOPLE, are “more quickly recognized” because there are more obvious symptoms.

Nonverbal learning disabilities, however, “really impact some of those non-verbal skills” such as “reading body language, reading social cues, all of the non-language areas, non-linguistic aspects of communication — like facial expression, tone and voice, things like that.”

Specifically, “they might have issues with the emotional tone or the social interpretation of other people’s tone or cues — interpreting sarcasm and humor and metaphors.”

It’s the “pragmatics of language that might be impacted, but they are obviously fully verbal and able to speak — and that’s not what nonverbal means.”

Feuer also notes that nonverbal learning disability is “not a subtype of autism,” although she says they “do share features.”

“A lot of kids with autism do have nonverbal learning disabilities because, in autism, some of those skills around communication — again, social cues and interpretation and expressing emotion and interpreting emotion, those can be impacted as well.”

“But autism has a myriad of other symptoms and features to make the diagnosis.”

With nonverbal learning disabilities, Feuer tells PEOPLE, there isn’t “one specific thing that’s the big red flag. It’s difficult to diagnose because it’s also ruling out other things.”

“It’s more difficult to catch and subtle,” she adds. “Kids may have difficulty with some mathematical concepts, understanding space and time. And they may have difficulty interpreting social cues, nuances of language and humor — and then not have some of the other features kids with autism also have like, for example, persistent interests.”

Kids with nonverbal learning disabilities may struggle with “directions or finding their way because their brain doesn’t really understand spatial orientation and how far things are.”

They also might not understand jokes — and may tend to “take things very literally because they’re just hearing the words, and not really adding whatever facial expression or body language or other social context cues that we use to interpret what people say.”

She goes on to say that there are longstanding misconceptions around all learning disorders.

“In general, the misconception about learning disabilities is that these people are not intelligent, or if you have a learning disorder, you can’t be intelligent — and that’s not true. Or if you have ADHD, you can’t be intelligent and, of course, that’s not true,” she says.

As Walz and his wife Gwen told PEOPLE exclusively in August, Gus “is brilliant, hyper-aware of details that many of us pass by, and above all else, he’s an excellent son and brother to his sibling.”

“We love our Gus,” Tim and Gwen, who also share daughter Hope, 23, told PEOPLE. “We are proud of the man he’s growing into, and we are so excited to have him with us on this journey.”