Speech, Language, and Communication Disorders and Differences: Differential Features
Domain 4 is the largest content area: differentiating speech, language, cognitive-communication, fluency, voice, and hearing disorders from one another and from normal variation. Items typically list distinguishing features and ask for the most likely diagnosis or the feature separating two candidates.
Speech sound disorders
- Articulation errors are motoric and consistent (one sound, one substitution). Phonological disorders reflect rule-based patterns - fronting, cluster reduction, final consonant deletion, stopping - quantified by percent consonants correct and process analysis.
- Childhood apraxia of speech: inconsistent errors across repeated productions, groping, disrupted transitions and prosody, better automatic than volitional speech, no weakness. Treat with high-trial, multimodal approaches such as dynamic temporal and tactile cueing.
- Dysarthria: consistent distortion across all subsystems with weakness, slowness, or incoordination; management emphasizes intelligibility and support strategies, not phoneme drilling alone.
Language and cognition
- Developmental language disorder: persistent deficits with normal hearing and nonverbal cognition; comprehension is often under-assessed.
- Aphasia: fluent (Wernicke, conduction, anomic) versus nonfluent (Broca, global, transcortical motor). Repetition separates conduction (impaired) from transcortical sensory (spared).
- Right hemisphere damage: aprosodia, tangential verbose discourse, poor inference and humor, left neglect.
- Alzheimer's disease shows early anomia with relatively preserved syntax; TBI drives executive, attentional, and social communication breakdown.
Fluency, voice, hearing, AAC
- Developmental stuttering: part-word repetitions and blocks with secondary behaviors; cluttering is rapid, disorganized, and poorly self-monitored.
- Evaluate resonance (hypernasality, velopharyngeal dysfunction) separately from phonation.
- Hearing loss: reduced audibility drives language delay. AAC does not require prerequisite cognitive or linguistic skills.
Worked example
A 4;6 child shows 55% consonants correct, inconsistent errors on the same word, groping, intact oral mechanism, and worse intelligibility in connected speech; he is inconsistently stimulable. Reasoning: inconsistency plus groping without weakness points to apraxia, not phonological disorder. Plan high-dose multimodal practice and avoid non-speech oral-motor exercises.
Traps that cost marks
- Scoring dialect features (final cluster reduction, copula absence, habitual "be") as errors.
- Diagnosing apraxia from a single inconsistent response.
- Using non-speech oral-motor exercises for speech sound disorders.
- Treating bilingual code-switching or a silent period as disorder.