Table 2.

Charting of CAS studies in speech symptoms category.

Study	Participants			Method/task	Dependent measures	Main results	Sensitivity/specificity?
	Group	n	Age range (years;months)
Thoonen et al. (1997)	CAS	11	6;2–7;9	Phonetic transcription; real-word and nonword repetition	- Consonant accuracy and error type	- Higher rate of errors in the CAS group	N
	TD	11	6;0–7;11			- Rate of substitution errors correlated with severity
						- The TD group showed larger benefit of real words vs. nonwords compared to CAS group
Shriberg et al. (1997a, 1997b)	sCAS	19	4;7–14;11	Phonetic transcription, prosodic coding; conversational speech samples	- Segmental accuracy, intelligibility index, prosody-voice profile	- Inappropriate stress may be a diagnostic marker for CAS	Y
	SD	73	Age-matched
Velleman & Shriberg (1999)	sCAS a	15	4;9–14;11	Phonetic transcription, lexical stress coding; conversational speech	- Lexical metrical patterns, syllable omissions, vowel augmentation	- Lexical stress errors were similar between groups	N
	SD	15	3;3–12;10			- Syllable omissions persisted to later ages in the sCAS group
Bahr (2005)	CAS	5	4;0–7;0	Clinical rating, acoustic analysis; CVC sequences from the Gesture Articulation Test	- Accuracy of gesture use	- The CAS and SD groups had similar number and type of speech gesture errors	N
	TD	5	4;0–7;0		- F2 slope, word duration
	SD	5	4;0–7;0			- The CAS group had longer word durations than the SD and TD groups
Highman et al. (2008)	sCAS	20	M = 4;0	Parent report (retrospective)	- Parent report on early vocalizations, babbling, and feeding behavior	- The sCAS and SLI groups had fewer infant vocalizations than the TD group	N
	LI	20	M = 5;0
	TD	20	M = 5;1			- The sCAS group had less babbling than the LI/TD groups
Aziz et al. (2010)	sCAS	10	4;0–6;0	Parent report, clinical rating, phonetic transcription; standardized testing, oral motor exam, spontaneous speech, nursery rhyme	- Segmental accuracy	- The sCAS group had lower segmental accuracy, increased difficulty with polysyllabic words and consonant clusters, and deficits in prosody compared to SD and TD groups	N
	SD	10	4;0–6;0		- Syllable shape accuracy
	TD	10	4;0–6;0		- Maximum repetition rate
					- Prosodic accuracy
Lewis et al. (2011)	SD	74	4;0–7;0	Clinical rating; standardized testing (phonological awareness, vocabulary, speeded naming), oral motor assessment	- DDK rate	- All 3 groups had deficits in phonological memory	N
	SD + LI	94	4;0–7;0		- Standardized test scores	- DDK rate did not differentiate groups
	CAS	41	4;0–7;0			- The SSD + LI and CAS groups had lower vocabulary and phonological awareness scores than the SSD-only group
Strand et al. (2013)	CAS	20	3;0–6;7	Clinical rating; standardized testing (DEMSS)	- Clusters based on DEMSS subscores	- DEMSS largely differentiated children with CAS, mild CAS, and other speech disorders (compared to expert diagnosis)	Y
	SD	61	3;0–6;3
Murray et al. (2015)	CAS	28	4;0–12;0	Phonetic transcription, lexical stress judgment; standardized testing, spontaneous speech sample, oral motor assessment	- 24 quantitative measures of segmental accuracy, rate, and presence of clinical features	- Model containing syllable segregation, lexical stress matches, PPC of polysyllables, and DDK accuracy had 91% diagnostic accuracy against expert diagnosis	Y
	CAS+	4
	Non-CAS b	15
Overby & Caspari (2015)	TD	2	4;5–6;4	Phonetic transcription; home videos from birth to age of 2 years: retrospective analysis	- Number of vocalizations	- The CAS group had fewer resonant and nonresonant productions, reduced phonetic inventories and limited syllable shapes at young ages compared to the TD group	N
	CAS	4	3;0–4;5		- Syllable shapes
					- Consonant inventories
					- Volubility
Iuzzini-Seigel et al. (2017)	CAS	10	4;7–17;8	Phonetic transcription; word and sentence repetition	- Token-to-token inconsistency, phonemic inconsistency	- Token-to-token inconsistency was sensitive and specific in differentiating between the CAS group from the SD and LI groups, especially in simpler stimuli	Y
	CAS + LI	10	4;7–17;8
	SD	10	4;7–17;8
	LI	9	4;7–17;8
	TD	9	4;7–17;8
Keske-Soares et al. (2018)	CAS	6	4;6–5;8	Standardized testing (DEMSS–Brazilian Portuguese version)	- DEMSS–Brazilian Portuguese subscores	- The CAS group had lower scores in accuracy and consistency than the SD and TD groups	N
	SD	6	4;6–5;8
	TD	6	4;6–5;8
Overby, Caspari, & Schreiber (2019)	CAS	7	3;5–8;8	Phonetic transcription; home videos from birth to age of 2 years: retrospective analysis	- Volubility; age of resonant consonant emergence, consonant diversity and frequency, syllable structure diversity and frequency	- Children later diagnosed with CAS were less voluble, used fewer resonant consonants, and had less diverse phonetic repertoires at young ages, and acquired resonant consonants later than children with SD and TD	N
	SD	5	3;5–8;8
	TD	5	3;5–8;8
Overby, Belardi, & Schreiber (2019)	CAS	10	3;0–8;11	Coding of home videos in three age brackets (7–12, 13–18, and 19–24 months): retrospective analysis	- Number of canonical babbles, number of noncanonical babbles, volubility, canonical babbling ratio	- Children later diagnosed with CAS used fewer canonical babbles, had lower volubility, and had later onset of canonical babbling compared to the SD and TD groups	N
	SD	4	3;0–8;11
	TD	6	3;0–8;11

Note. CAS = childhood apraxia of speech, developmental apraxia of speech, speech disorder–developmental apraxia of speech; Y/N = yes/no; TD = typically developing; sCAS = suspected childhood apraxia of speech; SD = speech sound disorder, phonological disorder, articulation disorder, multiple phonological disorder; CVC = consonant–vowel–consonant; F2 = second formant; SLI = specific language impairment; LI = language impairment; DDK = diadochokinetic; DEMSS = Dynamic Evaluation of Motor Speech Skill; PPC = percentage phonemes correct.

^asCAS for this study was called SD-DAS and split into two groups: SD-DASi (with inappropriate prosody) and SD-DASa (with appropriate prosody).

^b Non-CAS included dysarthria, phonological disorder, and submucosal cleft.