Developmental surface dyslexia and dysgraphia in a child with corpus callosum agenesis: an approach to diagnosis and treatment

Figures & data

Figure 1. Magnetic resonance imaging reveals a complete, isolated agenesis of the corpus callosum with colpocephaly; neurological convention.

Table 1. Cognitive background information.

Cognitive domain	Test	Age-corrected z-score
Standardized tests
Overall intelligence score	WISC-V	−0.92
Fluid reasoning	WISC-V Matrix reasoning, Figure weights	−1.18
Attention and processing
Processing speed	WISC-V Coding, Symbol search	−1.88
	TMT	−2.41
Alterness	KiTAP	−1.00
Flexibility	KiTAP	−2.41
Go/nogo	KiTAP	−1.75
Visuospatial abilities
Analysis and manipulation of spatial forms	WISC-V Block design, Visual puzzles	0.33
Copy of a complex figure	ROCFT	−1.23
Visual scanning	KiTAP	−2.41
Visual Memory
Immediate recall	ROCFT	−1.18
Delayed recall	ROCFT	−0.71
Verbal memory
Verbal short—and long-term memory
Verbal learning	VLMT	−1.65
Immediate recall	VLMT	1.65
Delayed recall	VLMT	1.65
Recognition	VLMT	−0.31
Verbal working memory	WISC-V Digit span	−0.41
Experimental tests	Statistics
Visuospatial abilities
Line bisection (n = 20)
Deviation to the left (in %)	Mean 8.5 (SD 0.04)
	Range 2–19
Line orientation^1	10/12

Note: WISC-V, Wechsler Intelligence Scale for Children WISC-V (Wechsler, 2017); TMT, Trail Making Test (Delis et al., 2001); VLMT, Verbaler Lern—und Merkfähigkeitstest (Helmstaedter et al., 2001); ROCFT, Rey Osterrieth Comlex Figure Test (Osterrieth, 1944); KiTAP (Zimmermann et al., 2002); ¹Stimuli from Benton Judgment of Line Orientation Test (Benton et al., 1978); z-scores below—2 are indicated in bold.

Table 2. Spoken language abilities.

Language domain	Test	Raw Score
Standardized language tests			Age-corrected z-score
Language comprehension
Spoken instructions	TTFC-2	41/50	0.52
Sentence comprehension	SET 5–10	11/12	0.15
Story comprehension	SET 5–10	10/10	2.41
Vocabulary
Expressive vocabulary	WWT	30/40	0.20
Naming	SET 5–10	38/40	0.84
Story telling	SET 5–10	8/8	2.41
Verbal fluency
Semantic fluency	RWT	23/2min	−0.47
Syntactic processing
Syntactic comprehension	TROG
Singular/plural formation	SET 5–10	18/18	2.41
Recognition of incorrect sentences	SET 5–10	12/12	2.41
Phonemic memory span
Memory span for vowels/syllables	PHOG	30/48	−0.25
Memory span for words/sentences	PHOG	15/24	−0.10

Note: AAT, Aachener Aphasie Test (Huber et al., 1983); TTFC-2, Token Test for Children (McGhee et al., 2007); SET 5-10, Sprachstandserhebungstest 5–10 (Petermann, 2018); WWT, Wortschatz—und Wortfindungstest (Glück, 2011); RWT, Regensburger Wortflüssigkeitstest (Aschenbrenner et al., 2001); TROG, Reception of Grammar Test (Bishop, 2003); PHOG, Phonematischer Gedächtnistest (Gruner et al., 2013)

Table 3. Orthographic processing

Language domainh	Test	Raw Score
Standardized language tests				Age-corrected z-score
Reading
Reading of words	SLRT II	5/min		−2.41
Reading of pseudowords	SLRT II	7/min		−2.41
Spelling to dictation	SLRT II	2/24		−2.41
Reading comprehension for words	AAT^1	30/30
Experimental language tests			Control group mean (range)	Group statistics (p-value)
Single letter processing
Identification		26/26	26.00 (26 - 26)	^2
Matching		26/26	26.00 (26 - 26)	^2
Naming		26/26	26.00 (26 - 26)	^2
Spelling to dictation		25/26	26.00 (26 - 26)	^2
Regular words
Reading accuracy		15/20	19.67 (19 −20)	0.013
Reading speed in seconds, mean (SD)		10.94 (2.35)	0.83 (0.80–0.90)	0.000
Comprehension of read words		20/20	20.00 (20 - 20)	^2
Spelling to dictation		35/40	37.00 (35 - 39)	0.399
Pseudowords
Reading accuracy		14/20	19.67 (19 - 20)	0.013
Reading speed in seconds, mean (SD)		10.01 (2.03)	1.20 (1.10 −1.30)	0.000
Spelling to dictation		18/20	19.00 (18 - 20)	0.402
Irregular words
Reading accuracy		5/20	17.67 (17 - 18)	0.002
Reading speed in seconds, mean (SD)		18.27 (5.79)	1.73 (1.50–1.90)	0.000
Comprehension of read words		19/20	20.00 (20 - 20)	^2
Spelling to dictation		4/40	36.33 (35 - 38)	0.002

Note: AAT, Aachener Aphasie Test (Huber et al., 1983); SLRT II, Salzburger Lese—und Rechtschreibtest (Moll & Landerl, 2010); ¹no norms for children; ²no statistics could be calculated since standard deviations of control group-results did not have a positive value; bold letters indicate z-scores below—2 or significant p-values

Table 4. Examples of spelling errors.

Error type	Target word (English translation)	IPA^1 translation	Patient’s output	Original patient’s output
Phonologically plausible spelling
	Vieh (cattle)	[ˈfiː]	Fi
	Lied (song)	[ˈliːt]	Lit
	Fell (fur)	[ˈfεl]	Fel
	Besteck (cutlery)	[bəˈʃtεk]	Beschtek
	Fähre (ferry)	[ˈfεːrə]	Fere
	Donnerstag (thursday)	[ˈdɔnɐstaːg]	Donastag
	Batterie (battery)	[batəˈriː]	Bateri
Phonologically plausible spelling and omissions
	Großstadt (city)	[ˈɡroːsʃtat]	Groschtat
	Mädchen (girl)	[ˈmεːtçən]	Mächen
	Gefahr (threat)	[ɡəˈfaːɐ̯]	Gefa
Phonologically plausible spelling, (omissions), and letter twists
	Handy (mobile phone)	[ˈhεndiː]	Henbi
	Pudding (pudding)	[ˈpʊdɪŋ]	Pubing
	Zwiebel (onion)	[ˈtsviːbεl̩]	Ziedel

¹ IPA, International Phonetic Alphabet.

Figure 2. Treatment schedule.

Table 5. Effect of treatment on spelling and reading of irregular words.

	Pre-treatment	Post-treatment (4 weeks)	χ² or t-test p-value
Spelling
Training words	0/80	41/80	<0.001
Untrained words	0/80	12/80	0.051
χ² p-value	1.000	< 0.001
Reading
Accuracy
Training words	55/80	78/80	<0.001
Untrained words	47/80	48/80	1.000
χ² p-value	0.188	< 0.001
Speed in seconds, mean (SD)
Training words	13.00 (4.72)	9.55 (2.78)	<0.001
Untrained words	13.30 (4.42)	12.51 (3.98)	0.016
t-test p-value	0.744	< 0.001

Figure 3. (a and b) Pre- and post-treatment white matter connectivity; The colour bar represents the connectivity indices (streamlines per mm³ brain region volume) from blue (connectivity index 0) to yellow (connectivity index ≥3); (c) White matter connectivity changes after treatment. The colour bar represents the pre- to post-treatment changes of connectome indices from blue (connectivity index decreased by -2) to yellow (connectivity index increased by +1). Note: FL, frontal lobe; CC, cingulate cortex; OL, occipital lobe; TL, temporal lobe; PL, parietal lobe; IN, insula.

Table 6. Pre- to post-treatment differences of average structural connectivities of each region to all other regions.

	Pre-treatment		Post-treatment		Difference pre- to post-treatment
	Mean (SD)	Range	Mean (SD)	Range	T (p)	Cohen’s d
Left hemisphere
Frontal lobe	1.45 (1.43)	0.02–3.58	1.50 (1.25)	0.05–2.82	0.23 (0.414)	0.10
Temporal lobe	1.02 (0.83)	0.14–2.15	1.31 (1.09)	0.22–2.81	2.55 (0.032)	1.14
Insula	1.36 (1.34)	0.31–3.58	1.39 (0.87)	0.60–2.82	0.13 (0.452)	0.06
Parietal lobe	1.83 (0.61)	1.31–2.71	1.86 (0.48)	1.12–2.30	0.14 (0.447)	0.06
Occipital lobe	1.14 (1.20)	0.02–2.71	1.27 (1.19)	0.05–2.81	0.68 (0.268)	0.30
Cingulate cortex	1.00 (0.95)	0.14–2.22	1.15 (0.82)	0.22–2.07	1.09 (0.168)	0.49
Right hemisphere
Frontal lobe	1.15 (1.04)	0.03–2.45	1.18 (0.48)	0.05–2.01	0.13 (0.453)	0.12
Temporal lobe	1.17 (0.87)	0.20–2.53	1.24 (1.06)	0.20–2.70	0.46 (0.336)	0.09
Insula	1.32 (0.90)	0.31–2.45	1.26 (0.78)	0.23–2.01	−0.44 (0.343)	0.41
Parietal lobe	2.34 (1.49)	1.16–4.82	1.98 (0.62)	1.40–3.04	−0.91 (0.206)	0.21
Occipital lobe	1.93 (1.88)	0.03–4.82	1.44 (1.35)	0.05–3.04	−0.53 (0.126)	0.09
Cingulate cortex	1.42 (0.92)	0.31–2.60	0.95 (0.78)	0.20–1.83	−2.84 (0.023)	0.38

Figure 4. White matter connectivity of the left and right occipital lobes before and after treatment, overlaid on the individual structural T1, neurological convention. The occipital lobes showed connectivity to ipsilateral temporal and frontal brain regions. Interhemispheric connectivity was possible through the anterior and posterior commissure. The colour-coding of tractography pathways is based on a standard red-green-blue (RGB) code that was applied to the vector in each brain area to show the spatial locations of terminal regions of each pathway (red for right-left, blue for cranial-caudal, and green for anterior-posterior). As pre- and post-treatment T1 images were taken at two different measurement time points, the orientation of the head within the scanner was not identical, and slices differed to some degree.

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Data availability

Fully anonymized data from this study can be made available on request.