SIMPLE DEVELOPMENTAL SPEECH DELAY: A FOLLOW-UP STUDY Kenneth M . McRae Eric Vickar
2 m m W m m m
m
2
s5
s
2 2 s: 0
2 P,
.s
s c
*
5
5>
2
4
868
The child of two to three years of age who is not talking is seen frequently in paediatricians’ offices. The concern of the parents is well-founded, since a number of developmental problems present clinically with delayed onset of speech. These include mental retardation, deafness, autism, various forms of brain damage and specific language disorders. However, there remains a group of children who, in the absence of such diagnoses, appear to have a simple developmental speech delay: that is, they appear to hear adequately, comprehend, relate appropriately and have no oral pathology interfering with sound and speech production. They also live in an environment in which stimulation is adequate, yet speech is absent or minimal. Experience in the Child Development Clinic, Winnipeg Children’s Hospital, with such children exhibiting ‘simple developmental speech delay’ (SDSD)has suggested a favourable prognosis for speech within a few years, certainly by the age of school entry. However, there has been no well-organized follow-up study to confirm this. Therefore, we followed the progress of a group of children with SDSD in order to study their subsequent speech and language development. There have been many studies investigating the progress of children with delayed speech and language development
(Ingram 1969, Morley 1972, Hall and Tomblin 1978, Klackenburg 1980, Bishop and Edmundson 1987, Coplan and Gleason 1988). However, many of these studies did not discriminate the purely speech-delayed children. The earlier reports of Ingram and Morley identified children similar to ours, but there are insufficient data for conclusions to be made. For example Ingram implied a prognosis in stating that ‘the majority of these children with normal subsequent language development will have no easily identifiable speech disorder by the age of seven or eight years’. Morley described similar children to ours among a larger group of patients with various problems in language development. She used the term ‘developmental expressive aphasia’ to describe these children and followed the progress of 74 so identified. She offered an optimistic prognosis for 50 of the children, whom she regarded as the ‘terminal gradient on a slope of normal development’. Unfortunately we could not ascertain the ages at which the children had been first assessed, nor the diagnostic instruments and procedures used. Other longitudinal studies combined children with delayed or absent speech with those whose early speech was characteristically unintelligible (Coplan and Gleason 1988). Klackenburg (1980) in his
follow-up study, did not separate out those affected by adverse socio-economic factors. Hall and Tomblin (1978) differentiated articulation from language disorders, in favour of the former for subsequent performance. We were particularly impressed by Bishop and Edmundson’s (1987) study, which attempted to distinguish transient from persistent language impairment. In their careful scrutiny they reported high predictability on the basis of test measures at four years. Fischel et al. (1989) reported on children with expressive language delay in a study similar to our own, but followed them for only a five-month period. In that period, however, one-third of the children showed improvement.
Method Population The charts of all children two to three years of age seen in the Child Development Clinic over one calendar year (1982) and who had been referred because of speech delay were reviewed. They had been referred by a physician, publichealth nurse, day-care centre or parents themselves because of the absence or paucity of speech. Speech was considered to be delayed if children had no speech or a vocabulary of less than 10 words. The average two- to three-year-old child can use at least threeword sentences and has a vocabulary of 350 words (Brown 1973). From approximately 100 children identified, a smaller group was selected whose delayed speech could be described as SDSD, using the following criteria: (1) The size of the child’s working vocabulary was assessed from parental report and the clinical examination. No child had speech appropriate for chronological age; at best, expressive vocabulary was less than 10 words, with no evidence of word-coupling. (2) All the children were assessed with the Yale Developmental Examination (Gesell and Amatruda 1947) and those with developmental quotients (DQS)
2 m m W m m m
m
2
s5
s
2 2 s: 0
2 P,
.s
s c
*
5
5>
2
4
868
The child of two to three years of age who is not talking is seen frequently in paediatricians’ offices. The concern of the parents is well-founded, since a number of developmental problems present clinically with delayed onset of speech. These include mental retardation, deafness, autism, various forms of brain damage and specific language disorders. However, there remains a group of children who, in the absence of such diagnoses, appear to have a simple developmental speech delay: that is, they appear to hear adequately, comprehend, relate appropriately and have no oral pathology interfering with sound and speech production. They also live in an environment in which stimulation is adequate, yet speech is absent or minimal. Experience in the Child Development Clinic, Winnipeg Children’s Hospital, with such children exhibiting ‘simple developmental speech delay’ (SDSD)has suggested a favourable prognosis for speech within a few years, certainly by the age of school entry. However, there has been no well-organized follow-up study to confirm this. Therefore, we followed the progress of a group of children with SDSD in order to study their subsequent speech and language development. There have been many studies investigating the progress of children with delayed speech and language development
(Ingram 1969, Morley 1972, Hall and Tomblin 1978, Klackenburg 1980, Bishop and Edmundson 1987, Coplan and Gleason 1988). However, many of these studies did not discriminate the purely speech-delayed children. The earlier reports of Ingram and Morley identified children similar to ours, but there are insufficient data for conclusions to be made. For example Ingram implied a prognosis in stating that ‘the majority of these children with normal subsequent language development will have no easily identifiable speech disorder by the age of seven or eight years’. Morley described similar children to ours among a larger group of patients with various problems in language development. She used the term ‘developmental expressive aphasia’ to describe these children and followed the progress of 74 so identified. She offered an optimistic prognosis for 50 of the children, whom she regarded as the ‘terminal gradient on a slope of normal development’. Unfortunately we could not ascertain the ages at which the children had been first assessed, nor the diagnostic instruments and procedures used. Other longitudinal studies combined children with delayed or absent speech with those whose early speech was characteristically unintelligible (Coplan and Gleason 1988). Klackenburg (1980) in his
follow-up study, did not separate out those affected by adverse socio-economic factors. Hall and Tomblin (1978) differentiated articulation from language disorders, in favour of the former for subsequent performance. We were particularly impressed by Bishop and Edmundson’s (1987) study, which attempted to distinguish transient from persistent language impairment. In their careful scrutiny they reported high predictability on the basis of test measures at four years. Fischel et al. (1989) reported on children with expressive language delay in a study similar to our own, but followed them for only a five-month period. In that period, however, one-third of the children showed improvement.
Method Population The charts of all children two to three years of age seen in the Child Development Clinic over one calendar year (1982) and who had been referred because of speech delay were reviewed. They had been referred by a physician, publichealth nurse, day-care centre or parents themselves because of the absence or paucity of speech. Speech was considered to be delayed if children had no speech or a vocabulary of less than 10 words. The average two- to three-year-old child can use at least threeword sentences and has a vocabulary of 350 words (Brown 1973). From approximately 100 children identified, a smaller group was selected whose delayed speech could be described as SDSD, using the following criteria: (1) The size of the child’s working vocabulary was assessed from parental report and the clinical examination. No child had speech appropriate for chronological age; at best, expressive vocabulary was less than 10 words, with no evidence of word-coupling. (2) All the children were assessed with the Yale Developmental Examination (Gesell and Amatruda 1947) and those with developmental quotients (DQS)
