Speech-Language Pathology: Assessment and Diagnosis
This domain tests screening, case history, standardized and nonstandardized assessment, language sampling, and differential diagnosis in speech, language, fluency, voice, and motor speech disorders.
Core rules
- Begin with hearing screening, oral mechanism examination, and case history. Use culturally and linguistically appropriate norms.
- Standardized tests yield standard scores and percentiles; criterion-referenced measures and language samples describe functional communication. Dynamic assessment estimates learning potential.
- A communication difference is not a disorder. Bilingual children should be assessed in both languages when possible.
- Differential diagnosis uses pattern, consistency, stimulability, and associated features. Articulation errors are phonetic; phonological errors follow rule-based patterns. Fluency disorders include stuttering-like disfluencies; voice assessment includes perceptual and acoustic measures.
Worked example
A 5-year-old has /s/ and /z/ distortions, is stimulable for correct production, has language scores within normal limits, normal hearing, and an intact oral mechanism. The pattern is isolated to two phonemes with phonetic distortion, not a rule-based process affecting a class of sounds. Diagnosis: articulation disorder. Reasoning: normal language, stimulability, and lack of a phonological pattern support a phonetic rather than phonological diagnosis. Treatment would target placement and practice rather than broad phoneme contrast.
Traps
Do not diagnose language disorder from a single low subtest score. Do not overidentify bilingual children using monolingual norms. Do not ignore hearing loss or oral-motor findings. Do not confuse apraxia with dysarthria: apraxia is planning/programming; dysarthria is execution.