The study was conducted in two preschools in the United States and New Zealand. This WWC
review includes only children attending the US site. The authors do not describe the location
or setting of the US preschool site.
The children participating in the study were between 3.1 and 5.2 years of age and all displayed
co-occurring speech and language impairments, including:
(a) a speech sound disorder (SSD) confirmed by a score of at least one standard deviation
below the mean on the Goldman-Fristoe Test of Articulation–Second Edition (GFTA-2);
(b) documentation of an expressive language score of at least one standard deviation
below the mean on the Structured Photographic Expressive Language Test–Preschool
2 (SPELT-P2) and/or one and one-half standard deviations below the mean MLU for the
child’s age based on Miller and Chapman’s (2000) normative data;
(c) age-appropriate receptive vocabulary, as confirmed by a score within one and one-half
standard deviations of the mean on the Peabody Picture Vocabulary Test–Third Edition
(d) normal functioning on oral motor assessment; and
(e) neurological, behavioral, hearing, and motor skills reported within normal limits.
Children in each geographic location were matched in pairs based on age and severity of
speech disorder (receptive vocabulary and gender also were considered). One child in each
pair was assigned to the intervention group, and the other was assigned to the comparison
group. One pair that spanned two cohorts was excluded from this review because the children
in this pair were not randomly assigned to conditions.
Children assigned to a phonemic awareness intervention participated in two six-week blocks of instruction, separated by a six- to seven-week break from the intervention. The intervention
included twice-weekly 60-minute instructional sessions in small-group settings, for a total
of 24 hours of instruction. The intervention involved phoneme awareness and letter/sound
knowledge, integrated with speech sound production. The intervention embedded phoneme
awareness and letter knowledge activities into clinician-directed play activities. Intervention
materials included an instructional manual, scripted lessons, material lists and patterns, stimulus
pictures, and activity books.
Children in the comparison group received a morphosyntactic intervention and a speech sound intervention provided in alternate weeks. The morphosyntactic intervention included
auditory awareness activities, focused stimulation activities, and elicited production activities.
The speech sound intervention included auditory awareness activities and production practice
in drill play and naturalistic activities. It did not target phoneme awareness or letter/sound
production directly. The time frame, time of instruction, and instructional setting were identical
to those in the intervention group. Intervention materials included an instructional manual,
scripted lessons, material lists and patterns, stimulus pictures, and activity books.
There were six outcomes used in the study: (a) finite morpheme composite (FMC), (b) letter name (LN), (c) mean length of utterance in morphemes (MLUm), (d) percent consonant correct (PCC), (e) phoneme identity (PID), and (f) /s/-cluster accuracy. Baseline data were collected two weeks prior to the start of the interventions, and outcome data were collected within two weeks following the conclusion of the second instructional block. Data also were collected during the break period between the two instructional blocks, but these intermediate outcomes are not considered in this review, since the full intervention had not been implemented. For a more detailed description of these outcome measures, see Appendix B.
Support for implementation
The instructional sessions for both intervention and comparison students were taught by
undergraduate senior or master’s-level speech-language pathology students. They were
supervised by certified doctoral students or professional speech-language pathologists. The
study authors trained staff to implement and supervise the interventions through reviews of
instructional manuals and videotaped examples of instructional sessions.