A Naming Test Told Them Apart

What the research found

This is a small, careful study of 60 children in Brazil. Thirty had a clinical diagnosis of developmental dyslexia. Thirty were typically developing readers of the same age. All were monolingual Portuguese speakers between seven and twelve years old, and nearly all attended private schools. The researchers set out to compare two things thought to underlie reading difficulty: rapid automatized naming, and explicit phonological awareness.

Rapid automatized naming, usually shortened to RAN, is a simple exercise. A child is shown a page filled with familiar items, such as letters, digits, colours, or common objects, and asked to name them aloud, one after another, as fast as they can. It measures not whether a child knows the items but how quickly and smoothly they can retrieve their names. Phonological awareness, by contrast, is the ability to notice and manipulate the sounds inside words, such as breaking a word into its syllables or spotting which words rhyme. It has long been treated as the central deficit in dyslexia.

On the naming tasks, the two groups came apart clearly. Children with dyslexia were slower on every RAN task, and the differences were moderate to large. In the language researchers use to describe effect size, the gaps ranged from a Cohen’s d of 0.66 for colours to 0.91 for letters, with digits at 0.82. A d of around 0.8 is conventionally called a large effect. Naming letters and digits, the tasks closest to reading itself, produced the biggest gaps.

The authors then asked a sharper question. Could naming speed alone sort children into the two groups? Using a statistical procedure that finds the single most useful cut-off, they found that the total time to name a page of letters did most of the work. Children who took roughly 34 seconds or longer tended to be the dyslexic readers. This one measure classified the children with 88.3 per cent overall accuracy. It correctly flagged 93.3 per cent of the children who had dyslexia, and correctly cleared 83.3 per cent of those who did not.

The phonological awareness test told a different story. On the standardised measure the researchers used, the two groups scored almost the same. The difference was a d of 0.20, small enough that the test could not reliably tell a dyslexic child from a typical reader. In this particular sample, the sound-based test that theory predicts should be central simply did not distinguish the groups, while the naming test did.

What it means for you and your child

The plain message is that how quickly a child names familiar letters can be a meaningful signal. If your child reads slowly and haltingly, and struggles to name a row of letters or numbers at speed, that is worth paying attention to. It is a low-effort thing to notice at home, though noticing is not the same as diagnosing.

Be careful with the 88 per cent figure. That is an accuracy rate the researchers obtained in the very same 60 children they used to find their cut-off. The authors are honest about this. When they tested their rule more rigorously, it showed signs of overfitting, meaning it was partly tuned to the quirks of this specific group and would likely perform less well on new children it had never seen. The 34-second threshold is not a diagnostic line to apply to your own child. It is a finding from one small study that needs replication in a fresh, independent sample before anyone should lean on it.

The sample matters too. These were 60 children, mostly boys, almost all from middle- and higher-income families attending private schools, learning to read in Portuguese. Portuguese has a more consistent relationship between letters and sounds than English does. Findings from a transparent language do not automatically transfer to English readers, and a group drawn from private schools may not resemble the wider population. This is a reason for interest, not a reason to generalise.

The quieter finding deserves equal weight. Phonological awareness has been treated for decades as the core of dyslexia, so it is striking that here it did not separate the groups. The authors do not claim it is unimportant. They flag that the particular test they used may have been part of the problem, and that measuring phonological processing well is genuinely difficult. One study finding no difference does not overturn a large body of evidence. It is a useful reminder that no single measure captures dyslexia, and that a child can have real reading difficulty without failing every test built to detect it.

If you are a parent weighing this, the sensible reading is modest. Naming speed is a promising, easy-to-observe marker, and slow letter naming alongside slow reading is a reasonable prompt to seek a proper assessment. But a diagnosis of dyslexia rests on a trained professional looking at reading, spelling, language history, and more, not on a stopwatch and a page of letters. This study sharpens what to watch for. It does not replace the assessment itself.