Executive functions in children with dyslexia

A sample of 47 children (ages 8-13 years) participated in the study: 24 who were dyslexic and 23 controls with typical development. A battery of neuropsychological tests was used.

Results:

Results revealed executive function difficulties among the dyslexic children when compared with controls, encompassing selective attention modulation processes, shifting, and inhibitory control. These difficulties appeared to be affected by phonological working memory deficits, typically associated with dyslexia.

Conclusion:

Our findings support the consensus among scholars regarding the central involvement of phonological skill dysfunctions in dyslexia.

Keywords:
Dyslexia; executive function; child; cognition

Variable	Dyslexic group	Control group
Age (Average)	11 (± 1.7)	10.9 (± 1.8)
Sex	18 male	16 male
Sex	6 female	7 female
School Type	15 public school	15 public school
School Type	9 private school	8 private school

CCPT Measures	Dyslexic group	Control group	p-value
Gross omissions^* * Control group outperformed dyslexic group; ISI: Inter-Stimulus Interval; Hit RT: Hit Reaction Time; Hit RT SE: Hit Reaction Time Standard Error.	21.3 (± 14.4)	8.7 (± 9.8)	0.01
Percentage of omissions^* * Control group outperformed dyslexic group; ISI: Inter-Stimulus Interval; Hit RT: Hit Reaction Time; Hit RT SE: Hit Reaction Time Standard Error.	6.2 (± 4.7)	2.7 (± 3)	0.02
Gross commissions^* * Control group outperformed dyslexic group; ISI: Inter-Stimulus Interval; Hit RT: Hit Reaction Time; Hit RT SE: Hit Reaction Time Standard Error.	22 (± 8.1)	19.6 (± 8.5)	0.4
Percentage of commissions	61.1 (± 22.6)	54.7 (± 23.8)	0.4
Hit RT^* * Control group outperformed dyslexic group; ISI: Inter-Stimulus Interval; Hit RT: Hit Reaction Time; Hit RT SE: Hit Reaction Time Standard Error.	477.7 (± 88.1)	389.4 (± 70.8)	0.001
Hit RT SE	15.6 (± 6.6)	8.9 (± 4.1)	0.2
Variability	35 (± 21)	20 (± 16.7)	0.06
Detectability (d’)	0.4 (± 0.4)	0.5 (± 0.4)	0.5
Response Style (b)	1.5 (± 2)	1.4 (± 2.3)	0.9
Perseverations	12.7 (± 15.7)	3.2 (± 6.8)	0.06
Hit RT block change	0.03 (± 0.06)	0.01 (± 0.03)	0.2
Hit SE block change	0.13 (± 0.1)	0.08 (± 0.1)	0.2
Hit RT ISI change	0.1 (± 0.07)	0.07 (± 0.06)	0.3
Hit SE ISI change	0.2 (± 0.2)	0.1 (± 0.2)	0.2

Measures		Dyslexic group	Control group	p-value
Phonological working memory
BCPR	2 syllables	9.8 (± 0.4)	10 (± 0.2)	0.08
	3 syllables	9.3 (± 0.6)	9.7 (± 0.6)	0.06
	4 syllables	8.8 (± 1)	9.5 (± 0.5)	0.6
	5 syllables^* * Control group outperformed dyslexic group; BCPR: Brazilian Children's Test of Pseudoword Repetition.	6.8 (± 2.2)	9.5 (± 0.8)	0.0005
Visuospatial working memory
Digit span	Forward	4 (± 0.6)	5.1 (± 1.1)	0.1
Digit span	Backward^* * Control group outperformed dyslexic group; BCPR: Brazilian Children's Test of Pseudoword Repetition.	2.8 (± 0.7)	4.1 (± 1)	0.007
Corsi block-tapping test	Forward	4.8 (± 1.3)	5.5 (± 1)	0.6
Corsi block-tapping test	Backward	4.3 (± 1.1)	4.9 (± 1.1)	0.06

Measures	Dyslexic group	Control group	p-value
Total cards	116.1 (± 19.5)	102.8 (± 19.8)	0.3
Correct answers	71 (± 13)	73.2 (± 13)	0.6
Percentage of errors	36.4 (± 15.3)	26.4 (± 14.6)	0.06
Percentage of perseverative answers	24.3 (± 17.6)	11.9 (± 6.6)	0.6
Percentage of perseverative errors^* * Control group outperformed dyslexic group.	20.4 (± 13.3)	11.1 (± 6.2)	0.04
Percentage of non-perseverative errors	15.8 (± 9.8)	14.8 (± 9.1)	0.7
Number of categories completed	4.4 (± 1.6)	5.3 (± 1.5)	0.07
Failure to maintain setting	0.9 (± 1.1)	1 (± 1.2)	0.9

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[1] Correspondence: Thais Barbosa; Departamento de Psicobiologia – UNIFESP; Rua Embaú, 54 – Vila Clementino; 04039-060 São Paulo SP, Brasil; E-mail: barbosa_thais@hotmail.com