Clues emerge from vowels of the brain.

The unusual spelling problems of two Italian-speaking men who suffered brain-damaging strokes in 1990 suggest that the brain uses separate mechanisms to identify vowels and consonants, according to a report in the Sept. 19 NATURE. The distinction between vowels and consonants may reflect "a psychological reality" rather than just a formal property of written languages, concludes psychologist Roberto Cubelli of Maggiore Hospital in Bologna, Italy.

Both men suffered damage on the left side of the brain and displayed marked difficulties with written vowels. In an examination who weeks after his stroke, one man omitted all vowels when writting his name, the town he lives in and the names of common objects, leaving blank spaces between correctly written consonants. For instance, instead of "Bologna," he wrote "B I gn." Although aware of his spelling errors, the man still could not come up with any vowels. This vowel-specific disturbance--never before identified in a brain-damaged patient, Cubelli says--largely improved in the week following testing.

The other man wrote vowels as well as consonants but made an overwhelming number of spelling errors involving vowels. Most of the time, he either replaced a vowel with an incorrect alternative vowel or transposed two vowels in the same word. For example, he wrote "dietro" (the Italian word for "behind") as "diatro," and "caro" (Italian for "dear") as "cora." The high proportion of vowel errors applied to both common and unusual words. Moreover, the error pattern appeared whether the man spelled the words aloud, wrote them by hand or used a typewriter. Yet when single vowels and syllables were read to him, he wrote them down without error.

Cubelli proposes that the representation of any word in the brain may include a breakdown of each letter's status as a consonant or vowel. Brain damage in the first man produced a total inability to pluck vowels from the cerebral vowel organizer, whereas in the second man it led to incorrect vowel choices, Cubelli maintains.

The contrast between vowels and consonants in the two men's writing problems remains unexplained, argues psychologist John C. Marshall of Radcliffe Infirmary in Oxford, England. A reversal of the first man's problem--an omission of all consonants from words--probably could not occur, he says.

In a commentary accompanying Cubelli's report, Marshall writes, "Once might reflect tht whn y wrt wtht vwls the message is still fairly clear, but e ou ie iou ooa...."