. 2014 Jun 7;1(3):215–227. doi: 10.1007/s40474-014-0019-1

Table 1.

Neuroimaging studies on SD

Article	Sample characteristics (study group)	Sample size (males)	Mean age (range)	Methods	Brain behaviour correlations	Decreases in study group (effect size)	Increases in study group (effect size)
Preston et al., 2014	Speech sound errors (SSE) Persistent errors Phonetic analysis <70 % PPC on ≥1 sound [79] No difference on CTOPP [80] between TD and SSE groups	SSE (n = 23, 18 M) TD (n = 54, 30 M)	SSE: 9y 9 m TD: 9y 11 m Total: 8y 6 m to 11y 11 m	VBM (whole brain)	No significant correlations between speech sound accuracy and gray and white matter in the SSE group alone	Reduced grey matter: R lingual gyrus ( d = 0.86) Reduced white matter: R lateral occipital gyrus (d = 0.95)	Increased grey matter: L Heschl's gyrus, L planum temporale, inferior L SMG LSTG (d = 1.05), R planum polare, R Heschl's Gyrus, R planum temporale (d = 0.95). Increased white matter : Splenium and anterior CC extending to cingulate (d = 0.83)
Kadis et al, 2013*	Childhood apraxia of speech (CAS) Moderate to severe , no dysarthria* Phonetic (GFTA)^a[81] and phonemic (HCAPP) analysis^a[82] VMPAC (focal oromotor; [83] Sequencing)^a	CAS (n = 11, 8 M) TD (n = 11, 5 M)	CAS: 4.7y TD: 4.8y	Cortical thickness ROIs in both hemispheres: IFG-PO; posterior SMG; posterior STG; inferior pre- and post-central gyri	No correlation between L SMG & any speech performance measures	None	Increased cortical thickness: L SMG
Liegeois et al, 2011	Affected members of KE family (FOXP2 mutation) CAS with mixed dysarthria	KE: (n = 4, 2 M) TD: (n = 4, 2 M)	Adults (not specified)	FMRI Overt nonword repetition VS. Listening to white noise ROIs: putamen		Reduced brain activity:L cerebellum (lob IX), R anterior cingulate, L + R MOG, R SFG, R SMA, L lingual gyrus, L rolandic operculum (extending into precentral gyrus), L + R putamen (small volume correction);	Increased brain activity Not reported
Tkach et al., 2011	Speech sound disorder (SSD) – History moderate to severe SSD (GFTA & KLPA). [81, 84] 5/6 typical adult level production by school age and time of scan Phonetic & phonemic analysis	SSD: (n = 6, 5 M) TD: N = 7**	Adolescents: SSD: 17y TD: 18y	fMRI Overt nonword repetition VS. Rest		Reduced brain activity: R IFG (BA45 + BA46); R MTG	Increased brain activity: L postcentral gyrus; L SFG; L + R MFG; Lmedial frontal gyrus; L IFG (BA47); L sub-gyral frontal lobe; L STG; L AG; L IPL; L SMG; L CG; L + R IOG; R cuneus; R lingual G; L + R MOG; L putamen; L hypthothalamus L + R declive R culmen.
Preston et al., 2012	Speech sound errors (SSE) Persistent errors Phonetic analysis <70 % PPC on ≥1 sound [79] Large effect sizes for group comparison (TD vs SSE) on some WJ, [85] CTOPP [80] subtests	SSE: (n = 17, 14 M) TD: (n = 17, 14 M)	SSE: 9y 7 m TD: 9y 10 m Total Range: 8y 6 m to 10y 10 m	fMRI Auditory and visual presentation, word and nonwords. Tasks: Covert naming, matching using button press		Reduced brain activity: Auditory presentation: L + R orbital gyrus; L temporal pole; R ITG; L MTG Visual presentation: L SOG, L cerebellum	Increased brain activity: Auditory presentation: L + R inferior SPL; precuneus; R SMG and Postcentral gyrus; L fusiform; L + R STG; posterior & anterior cingulate; R MFG; cuneus; L gobus pallidus; R lingual G; L cerebellum; R temporal pole; L MFG; R SFG; L middle occipital gyrus; L insula; R precentral gyrus Visual presentation: precuneus, R STG/STS, anterior cingulate, L + R fusiform, posterior cingulate, L MFG/SFG, L STS/MTG, L SPL, R MTG, L globus pallidus, R anterior IPS, R lingual gyrus, L postcentral gyrus, L IFG, R precentral gyrus, L + R MFG, R parahippocampal gyrus

Article

Sample characteristics (study group)

Sample size (males)

Mean age (range)

Methods

Brain behaviour correlations

Decreases in study group (effect size)

Increases in study group (effect size)

Preston et al., 2014

Speech sound errors (SSE)

Persistent errors

Phonetic analysis

<70 % PPC on ≥1 sound [79]

No difference on CTOPP [80] between TD and SSE groups

SSE (n = 23, 18 M)

TD (n = 54, 30 M)

SSE: 9y 9 m

TD: 9y 11 m

Total: 8y 6 m to 11y 11 m

VBM (whole brain)

No significant correlations between speech sound accuracy and gray and white matter in the SSE group alone

Reduced grey matter:

R lingual gyrus ( d = 0.86)

Reduced white matter:

R lateral occipital gyrus (d = 0.95)

Increased grey matter:

L Heschl's gyrus, L planum temporale, inferior L SMG LSTG (d = 1.05),

R planum polare, R Heschl's Gyrus, R planum temporale

(d = 0.95).

Increased white matter :

Splenium and anterior CC extending to cingulate (d = 0.83)

Kadis et al, 2013*

Childhood apraxia of speech (CAS)

Moderate to severe , no dysarthria*

Phonetic (GFTA)^a[81] and phonemic (HCAPP) analysis^a[82]

VMPAC (focal oromotor; [83] Sequencing)^a

CAS (n = 11, 8 M)

TD (n = 11, 5 M)

CAS: 4.7y

TD: 4.8y

Cortical thickness

ROIs in both hemispheres: IFG-PO; posterior SMG; posterior STG; inferior pre- and post-central gyri

No correlation between L SMG & any speech performance measures

None

Increased cortical thickness:

L SMG

Liegeois et al, 2011

Affected members of KE family (FOXP2 mutation)

CAS with mixed dysarthria

KE: (n = 4, 2 M)

TD: (n = 4, 2 M)

Adults (not specified)

FMRI

Overt nonword repetition VS. Listening to white noise

ROIs: putamen

Reduced brain activity:L cerebellum (lob IX), R anterior cingulate, L + R MOG, R SFG, R SMA, L lingual gyrus, L rolandic operculum (extending into precentral gyrus), L + R putamen (small volume correction);

Increased brain activity

Not reported

Tkach et al., 2011

Speech sound disorder (SSD) –

History moderate to severe SSD (GFTA & KLPA). [81, 84]

5/6 typical adult level production by school age and time of scan

Phonetic & phonemic analysis

SSD: (n = 6, 5 M)

TD: N = 7**

Adolescents:

SSD: 17y

TD: 18y

fMRI

Overt nonword repetition VS. Rest

Reduced brain activity:

R IFG (BA45 + BA46); R MTG

Increased brain activity:

L postcentral gyrus; L SFG; L + R MFG; Lmedial frontal gyrus; L IFG (BA47); L sub-gyral frontal lobe; L STG; L AG; L IPL; L SMG; L CG; L + R IOG; R cuneus; R lingual G; L + R MOG; L putamen; L hypthothalamus L + R declive R culmen.

Preston et al., 2012

Speech sound errors (SSE)

Persistent errors

Phonetic analysis

<70 % PPC on ≥1 sound [79]

Large effect sizes for group comparison (TD vs SSE) on some WJ, [85] CTOPP [80] subtests

SSE: (n = 17, 14 M)

TD: (n = 17, 14 M)

SSE: 9y 7 m TD: 9y 10 m Total Range: 8y 6 m to 10y 10 m

fMRI

Auditory and visual presentation, word and nonwords.

Tasks: Covert naming, matching using button press

Reduced brain activity:

Auditory presentation: L + R orbital gyrus; L temporal pole; R ITG; L MTG

Visual presentation:

L SOG, L cerebellum

Increased brain activity:

Auditory presentation:

L + R inferior SPL; precuneus; R SMG and Postcentral gyrus; L fusiform; L + R STG; posterior & anterior cingulate; R MFG; cuneus; L gobus pallidus; R lingual G; L cerebellum; R temporal pole; L MFG; R SFG; L middle occipital gyrus; L insula; R precentral gyrus

Visual presentation: precuneus, R STG/STS, anterior cingulate, L + R fusiform, posterior cingulate, L MFG/SFG, L STS/MTG, L SPL, R MTG, L globus pallidus, R anterior IPS, R lingual gyrus, L postcentral gyrus, L IFG, R precentral gyrus, L + R MFG, R parahippocampal gyrus

Study Group refers to SSD, SSE or CAS here. Note that diagnoses were made by the authors

Abbreviations: AG angular gyrus, ASD Autistic Spectrum Disorder, CAS childhood apraxia of speech, CC corpus callosum, CG cingulate gyrus, CTOPP Comprehensive Test of Phonological Processing, GFTA Goldman Fristoe Test of Articulation, CAPP Hodson Computerised Analysis of Phonological Processes, IFG inferior frontal gyrus, IOG inferior occipital gyrus, ITG inferior temporal gyrus, KLPA Khan-Lewis Phonological Analysis, L left hemisphere, LI language impairment, MFG middle frontal gyrus, MOG middle occipital gyrus, MTG middle temporal gyrus, PPC percentage of consonants correct, r right hemisphere, ROI region of interest, SFG superior frontal gyrus, SMA supplementary motor area, SMG supramarginal gyrus, SOG superior occipital gyrus, SPL superior parietal lobule, SSD speech sound disorder, SSE speech sound errors, STG superior temporal gryus, STS superior temporal sulcus, TD typical development, VBM voxel based morphometry, WJ Woodcock-Johnson

* Note that this is an intervention study and we will here only review neuroimaging findings reported before intervention—where the SSE and control groups are of equal size.

** Gender not reported

^aOnly report magnitude of difference after therapy