Evaluation and Management of the Child with Speech Delay

American Family Physician,  June, 1999  by Alexander K. C. Leung,  C. Pion Kao

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A delay in speech development may be a symptom of many disorders, including mental retardation, hearing loss, an expressive language disorder, psychosocial deprivation, autism, elective mutism, receptive aphasia and cerebral palsy. Speech delay may be secondary to maturation delay or bilingualism. Being familiar with the factors to look for when taking the history and performing the physical examination allows physicians to make a prompt diagnosis. Timely detection and early intervention may mitigate the emotional, social and cognitive deficits of this disability and improve the outcome.

Speech is the motor act of communicating by articulating verbal expression, whereas language is the knowledge of a symbol system used for interpersonal communication.1 In general, a child is considered to have speech delay if the child's speech development is significantly below the norm for children of the same age. A child with speech delay has speech development that is typical of a normally developing child of a younger chronologic age; the speech-delayed child's skills are acquired in a normal sequence, but at a slower-than-normal rate.2

Speech delay has long been a concern of physicians who care for children. The concern is well founded, because a number of developmental problems accompany delayed onset of speech. In addition, speech delay may have a significant impact on personal, social, academic and, later on, vocational life. Early identification and appropriate intervention may mitigate the emotional, social and cognitive deficits of this disability and may improve the outcome.

Normal Speech Development

To determine whether a child has speech delay, the physician must have a basic knowledge of speech milestones. Normal speech progresses through stages of cooing, babbling, echolalia, jargon, words and word combinations, and sentence formation. The normal pattern of speech development is shown in Table 1.3

Epidemiology

Exact figures that would document the prevalence of speech delay in children are difficult to obtain because of confused terminology, differences in diagnostic criteria, unreliability of unconfirmed parental observations, lack of reliable diagnostic procedures and methodologic problems in sampling and data retrieval. It can be said, however, that speech delay is a common childhood problem that affects 3 to 10 percent of children.4-6 The disorder is three to four times more common in boys than in girls.5,7

Etiology

Speech delay may be a manifestation of numerous disorders. Causes of the problem are listed in Table 2.

Mental retardation

Mental retardation is the most common cause of speech delay, accounting for more than 50 percent of cases.8 A mentally retarded child demonstrates global language delay and also has delayed auditory comprehension and delayed use of gestures. In general, the more severe the mental retardation, the slower the acquisition of communicative speech. Speech development is relatively more delayed in mentally retarded children than are other fields of development.

In approximately 30 to 40 percent of children with mental retardation, the cause of the retardation cannot be determined, even after extensive investigation.9 Known causes of mental retardation include genetic defects, intrauterine infection, placental insufficiency, maternal medication, trauma to the central nervous system, hypoxia, kernicterus, hypothyroidism, poisoning, meningitis or encephalitis, and metabolic disorders.9

Hearing loss

Intact hearing in the first few years of life is vital to language and speech development. Hearing loss at an early stage of development may lead to profound speech delay.

Hearing loss may be conductive or sensorineural. Conductive loss is commonly caused by otitis media with effusion.10 Such hearing loss is intermittent and averages from 15 to 20 dB.11 Some studies have shown that children with conductive hearing loss associated with middle ear fluid during the first few years of life are at risk for speech delay.4,11 However, not all studies find this association.12 Conductive hearing loss may also be caused by malformations of the middle ear structures and atresia of the external auditory canal.

Sensorineural hearing loss may result from intrauterine infection, kernicterus, ototoxic drugs, bacterial meningitis, hypoxia, intracranial hemorrhage, certain syndromes (e.g., Pendred syndrome, Waardenburg syndrome, Usher syndrome) and chromosomal abnormalities (e.g., trisomy syndromes). Sensorineural hearing loss is typically most severe in the higher frequencies.

Maturation delay

Maturation delay (developmental language delay) accounts for a considerable percentage of late talkers. In this condition, a delay occurs in the maturation of the central neurologic process required to produce speech. The condition is more common in boys, and a family history of "late bloomers" is often present.13 The prognosis for these children is excellent, however; they usually have normal speech development by the age of school entry.14