Receptive vocabulary, expressive vocabulary, and speech production of boys with fragile X syndrome in comparison to boys with down syndrome.

Boys with fragile X syndrome with (n = 49) and without (n = 33) characteristics of autism spectrum disorder, boys with Down syndrome (39), and typically developing boys (n = 41) were compared on standardized measures of receptive vocabulary, expressive vocabulary, and speech administered annually over 4 years. Three major findings emerged. Boys with fragile X without autism spectrum disorder did not differ from the younger typically developing boys in receptive and expressive vocabulary and speech production when compared at similar levels of nonverbal cognitive skills. Boys with fragile X without autism spectrum disorder and typically developing boys had higher receptive vocabulary and speech production than did boys with Down syndrome. There were mixed patterns of results for the boys with fragile X and characteristics of autism spectrum disorder.

Articulation rate and vowel space characteristics of young males with fragile X syndrome: preliminary acoustic findings.

PURPOSE: Increased speaking rate is a commonly reported perceptual characteristic among males with fragile X syndrome (FXS). The objective of this preliminary study was to determine articulation rate-one component of perceived speaking rate-and vowel space characteristics of young males with FXS. METHOD: Young males with FXS (n = 38), developmental age (DA)-matched males (n = 21), and chronological age (CA)-matched males (n = 16) were audiotaped while engaged in spontaneous conversation and a picture-naming task. Articulation rate in syllables per second during intelligible utterances and vowel space area/dispersion measures were acoustically determined for each speaker. RESULTS: Males with FXS did not articulate significantly faster than CA-matched males. Area and dispersion of the acoustic vowel space also were similar between the 2 groups. Males with FXS, however, used significantly shorter utterances and had a tendency to pause less often than CA-matched males. In addition, males with FXS exhibited greater intraspeaker variability of formants associated with the vowel /a/. CONCLUSIONS: These preliminary findings suggest that articulation rate may not be a primary factor contributing to perceived speaking rate of males with FXS. Limitations of the study relative to speech production tasks and utterance intelligibility are discussed.

A comparison of oral structure and oral-motor function in young males with fragile X syndrome and Down syndrome.

This study compared the oral structure and oral-motor skills of 59 boys with fragile X syndrome (FXS), 34 boys with Down syndrome (DS), and 36 developmentally similar typically developing (TD) boys. An adaptation of the J. Robbins and T. Klee (1987) Oral Speech Motor Protocol was administered to participants and their scores on measures of oral structure and accuracy on speech motor and oral-motor tasks were analyzed. Boys with FXS scored lower than TD boys on oral structure, most oral function tasks, and all speech function tasks. Boys with DS scored lower than boys with FXS and TD boys on oral structure, and lower than TD boys on 1 oral function task and all speech function tasks. Boys with FXS and TD boys scored higher on speech function than oral function tasks, while boys with DS scored higher on oral function than speech function tasks. Boys with FXS and boys with DS repeated single syllable words with greater accuracy than multiple syllable words, while the TD boys produced both types of words with equal accuracy. These results suggest that boys with FXS and boys with DS exhibit atypical oral structure and motor function, yet differ in specific oral-motor patterns.

Auditory brainstem responses in young males with Fragile X syndrome.

Fragile X syndrome (FXS) is the most common inherited cause of mental retardation resulting in developmental delays in males. Atypical outer ear morphology is characteristic of FXS and may serve as a marker for abnormal auditory function. Despite this abnormality, studies of the hearing of young males with FXS are generally lacking. A few studies have suggested that a significant proportion of individuals with FXS demonstrate prolonged auditory brainstem response (ABR) latencies. The purpose of this study was to determine whether young males with FXS display atypical auditory brainstem function compared to typically developing males when conductive and sensorineural hearing loss are ruled out as possible contributors to atypical findings. Participants were 23 males with FXS, 21 typically developing males who were matched for developmental age, and 17 typically developing males who were matched for chronological age. A battery of tests to assess peripheral hearing, cochlear function, and auditory pathway integrity through the level of the brainstem was completed. Males with FXS were similar to typically developing males who were matched for developmental age level or chronological age level on all measures. They had normal hearing sensitivity and middle ear function and scored similar to the typically developing children on the measures of auditory brainstem pathway integrity. In summary, ABRs in young males with FXS were within normal limits.