Quantitative Sensory Testing to Study Pain Perception in Autism

Pain Perception in Autism. Study Through Quantitative Sensory Testing and Psychophysiological Correlates

This study aims at assess sensory perception, and pain perception, in neurodivergent children and adolescent in the autism spectrum. To achieve this goal, the quantitive sensory testing (QST), a controlled and replicable protocol, will be used, to assess perception in different sensory modalities: heat sensations, mechanical detection threshold and pain threshold. As secondary aim, the cortical processing of thermal painful stimuli will be collected through electroencephalography (EEG) in order to investigate if there are differences in the cortical processing of painful stimuli between clinical sample and control sample, and if it could be associated with differences in the subjective experience between the two groups. Finally, it will be explored the association between such differences, and indexes of psychopathology and dispositional measures.

Study procedure imply the following steps: 1. Eligibility assessment according to inclusion and exclusion criteria. 2. Administration of questionnaires and scales for the characterization of clinical aspects of autism: Short sensory profile; The Autism Spectrum Quotient: Children's Version; Vineland Adaptive Behaviour Scales-Second Edition. The Vineland Adaptive Behaviour Scales-Second Edition; The Child Behavior Checklist (CBCL). 3. Administration of Quantitative Sensory Testing to study sensory thresholds and perception. 4. EEG recording at rest as well as while receiving heat stimuli to study cortical processing of salient thermal stimuli.

The QST protocol, implies the administration of 7 short sensory test in order to measure up to 13 parameters, which can be grouped as follows: thermal detection thresholds for the perception of cold, warm and paradoxical heat sensations, thermal pain thresholds for cold and hot stimuli, mechanical detection thresholds for touch and vibration, mechanical pain thresholds and sensitivity for pinprick and blunt pressure, vibration detection threshold and pressure pain threshold. Previous research with QST in neurodevelopmental disorders used modified version of the whole protocol, to make it suitable and tolerable for different clinical condition such as developmental delay including motor, communicative, and cognitive impairments. Thus, we will also administer the most suitable and tolerable version of the QST according to each patient condition and needs, for example we plan to reduce the number of stimuli for each stimulation side when needed, in order to reduce stimulus trial duration as well. The whole procedure will be implemented in a kids friendly environment, colourful and comfortable, and sensory stimuli will be adapted in order to avoid fearfulness of the stimuli, thus each stimulation will be presented as a game to be played with a specific animal, and each device and instrument will be covered with animals pictures according to the game it represents. Overall QST last about 1h 30 minutes, it will be divided in at least two sessions according to patients' needs.

The EEG recording consist in the cap montage at first, then a short accommodation with the sensory stimuli in order to find an intensity value for a moderate painful stimulus, to be used for the stimulation. After the preparation/accommodation, the eeg recording will start while a series, up to 30 thermal stimuli, will be delivered to the patients' hand dorsum. The whole eeg recording last about 30 minutes and it will be implemented in one session only.

Inclusion Criteria for the clinical sample:

• Children and adolescent
• age between 5 and 17 years old
• Autism diagnosis according to DSM-V criteria

Inclusion Criteria for the control sample:

• healthy children and adolescent (without neurological, and psychiatric, diagnoses)
• age between 5 and 17 years old

Exclusion Criteria:

Comorbidities with (for the clinical sample) or diagnosis of (for the control sample):

• peripheral neuropaties;
• psychiatric diagnosis as psychosis,
• Tourette Syndrome,
• neurological diagnoses as epilepsy,
• sensory deficit or loss;
• genetic diseases