Dyslexia is a frustrating disorder that gives otherwise smart people trouble with reading. Nobody knows exactly what causes it, but one popular hypothesis is that the root of the problem is a deficit in the brain's ability to process sounds, especially during childhood. Kids who have a hard time parsing all those talky sounds that grownups make also struggle to learn the connections between speech sounds and words on a page. And that's what causes the reading difficulties, or so the thinking goes.

But if parsing sounds is really the whole problem, how do you explain dyslexic musicians? After all, musicians are supposed to excel at making sense of sound. But a small number of them, it turns out, have dyslexia. Now, a team of researchers at Hebrew University in Israel has tried to sort this problem out–by rounding up, for the first time, a cohort of dyslexic musicians and testing their language abilities.

The researchers, led by psychologist Merav Ahissar, tested 52 musicians on basic auditory perception (such as their ability to tell similar tones or similar time intervals apart) as well as auditory perception related specifically to music (distinguishing different rhythms or melody) or language (like the ability to discriminate words from similar-sounding non-words they heard). They also gave the musicians memory tests and tested their reading speed and accuracy.

It took years, in part because dyslexic musicians are rare, Ahissar says. (No one knows exactly how rare though – Ahissar says she couldn't find any studies on whether the disorder is any more or less common in musicians than in the general population, where estimates range from one to ten percent). Eventually, Ahissar's student Atalia Weiss, a graduate of Hebrew University's music academy, was able to recruit 24.

What did they find? On most tests of auditory perception, the dyslexic musicians scored as well as their non-dyslexic counterparts, and better than the general population. Where they performed much worse was on tests of auditory working memory, the ability to keep a sound in mind for a short time (typically seconds). In fact, the dyslexic musicians with the poorest working memory tended to have the lowest reading accuracy. Those with better working memory tended to be more accurate.

Writing in the February issue of the journal Neuropsychologia, Ahissar and her team suggest that auditory working memory might be a bottleneck for the performance of people with dyslexia. If so, that might shift more of researchers' attention to memory-related brain regions in addition to the auditory areas that have gotten most of the attention in dyslexia research.

The results make a lot of sense. Learning a language requires making connections between sounds, what they mean, and how writing represents them, and memory is a crucial part of that process, says Nina Kraus, a neuroscientist who studies music and language at Northwestern University. "If you can't remember a sound, you can't make the connection."

In other words, to become a linguisitic virtuoso, memory is just as important as perception.