Childhood Apraxia of Speech: Experience Dependent Changes Induced by Treatment

Childhood Apraxia of Speech (CAS) is a severe speech-language disorder whose aetiological, neuroanatomical correlates are largely unknown. Furthermore, little is known about the neuroplastic effects induced by different treatment approaches and their relationships with the potential changes in the speech behavioural features that express the core deficit of CAS.

Twenty four children with idiopathic CAS will be enrolled in a multidisciplinary study aimed at analysing the behavioural and neuroanatomical effects of a specific rehabilitative approach, PROMPT (PROMPTs for Restructuring Oral Muscular Phonetic Targets), that employs tactile-kinesthetic-proprioceptive cues vs a traditional speech-language treatment. The children will be allocated in two arms, one receiving a seven month cycle of individual PROMPT treatment, the other a traditional speech and language treatment for the same amount of time.The pre- and post-treatment speech and language performances and DTI and volumetric MR data will be compared in the two groups.

Background: Childhood Apraxia of Speech (CAS) is a severe speech-language disorder whose etiological, neuroanatomical and genetic correlates are largely unknown. In this trial the effects of an innovative rehabilitative approach, PROMPT (PROMPTS for Restructuring Oral Muscular Phonetic Targets) will be evaluated from a behavioral and neuroanatomical point of view.

Objective: the current study is aimed to assess speech-language and white matter microstructure and volumetric changes induced by the PROMPT treatment.

Participants: Twenty-two Children with CAS aged 4 -12 years are enrolled and assigned to a PROMPT treatment (PROMPT-t ) or a Language and Non-Speech Oral Motor-treatment group (LNSOM-t).

Methods: All children with CAS will undergo a comprehensive clinical, neurological and speech-language assessment. The following procedures will be applied: a) anamnestic interview b) oral non verbal and verbal movements eveluation c) phonetic inventory, accuracy and consistency of speech d) DDK (Diadochokinetic rate, receptive and expressive vocabulary and grammar tests; f) spontaneous language analysis. These multiple measurements were aggregated and converted into a speech and language composite score.

MRI data will be acquired using a 1.5 T MR scanner. Structural images obtained with a 3D isotropic T1 weighted sequence will be analysed to evaluate volumetric alterations, to investigate cortical thickness and automatically delineate various Regions of Interest (ROIs). HARDI images will be acquired using 32 gradient directions and will be processed using tools available in FSL and MRtrix. Tract-based spatial statistics (TBSS) will be used to statistically analyse images of FA and mean diffusivity. Fiber tracts will be calculated using constrained spherical deconvolution and probabilistic tractography. Connectomes will be calculated by combining ROIs obtained from the structural images with tractography. Network-based analysis will be used to statistically analyse connectomes.

Speech and language assessment and brain MRI VBM and DTI analysis will be performed at baseline and at the end of the treatment.

Statistical analysis: Paired t-test on pre and post treatment behavioural and MRI/DTI measures will be performed to assess the changes within each of the two groups. Moreover, comparisons between the two groups at T0 and T1 will be performed by means of non parametric tests.

Evaluation of potentially training-induced changes of brain structural connectivity may provide further support to the hypothesis that CAS is due to a disruption of networks subserving the speech production system.

Eligibility Criteria:
Inclusion Criteria:

* Diagnosis of idiopathic CAS based on the presence of specific diagnostic features of apraxia of speech (see ASHA and Strand et al's criteria) and on a comprehensive clinical and neurological assessment.
* Non-verbal IQ within the normal range at standardized tests of intelligence.
* Normal structural brain MRI.
* Acquisition of parents' informed consent to the execution of behavoiural and neuroradiological assessment at baseline and to perform speech/language treatment.

Exclusion Criteria:

* Orofacial structural abnormalities.
* Known pathologies of neurological, neurometabolical and genetic etiologies.
* Audiological deficits.
* Epilepsy.
* Intellectual disability.
* Autism spectrum disorder.