Two-point discrimination (i.e., is the ability to discern that two nearby objects touching the skin are truly two distinct points, not one), will be assessed with an Aesthesiometer. This tool has two pinches which can come closer or further from each other. With the vision of the child occluded and the change of the distance between the two pinches, this test can determine the minimum distance that the two impressions can be distinguished by the child

It is an assessment tool to measure the assisting hand performance in children with UCP. It can be used for children aged between 18 months and 18 years, with playful session made of semi-structured activities calibrated on the different ages (different board games). This tool has been identified as the primary outcome measure and will be used at all evaluation times. The assessment is videotaped and the scoring is based on the video. This test will be performed also to the sample of children with TD.

It is a valid and reliable criterion-referenced test for evaluating upper limb movement quality in children with a neurological impairment aged 2.5 to 15 years. It consists of 14 unimanually tested items including reach, pointing, manipulation, grasp, release, and pro-/supination. Only the affected hand will be tested and it lasts approximately 15 minutes.

Manual dexterity will be assessed using the BBT. The child will be seated on an adjusted chair in front of a two-compartment box placed on a table, one compartment containing a total of 150 blocks. The goal is to transport as many blocks as possible, one at a time, from one compartment to the other with the same hand. The two hands will be both tested starting from the dominant one.

NEPSY evaluates the child's neurocognitive development. In the study the investigators will assess four subtests:

• The Imitating Hand Positions subtest which assesses imitation and requires the child to imitate, separately with the dominant or non-dominant hand, various hand/finger positions performed by the examiner.
• The Manual Motor Sequences set assesses planning and coordination of sequences of hand movements and the child will be asked to imitate five times series of rhythmic unimanual or bimanual movements shown by the examiner.
• The Inhibition subtest and the Auditory Attention and Response Set subtest to assess the attention and executive functioning. The child will be asked to name different shapes according to examiner's instructions or point at the right time in a series of words said by the examiner.
• The Verbal Fluency Subtest, which evaluates cognitive flexibility in a word production task within a specific semantic or phonemic category.

This scale evaluates non-verbal intelligence and cognitive abilities. In this study, the investigators will use the Sustained Attention subtest, which assesses visual attention and consists of repetitive barrage tasks to be performed in a predefined time.

VMI is a paper-pencil test used to determine the level of integration between visual and motor systems. The child will be asked to copy different geometric forms shown on the paper within a certain time frame.

MOXO evaluates sustained attention and is provided via a computer. The test requires the child to sustain attention over a continuous stream of stimuli (visual or auditory) and to respond to a specific target stimulus.

The Corsi block-tapping test evaluates visuo-spatial, short-term and working memory. The child is asked to retrieve a sequence previously seen by the examiner by tapping blocks with the preferred finger following the same order for the forward condition or reversing the order for the backward condition.

BRIEF is a questionnaire filled in by the parents/legal guardians and dives into everyday behavior associated with specific domains of the executive functions (i.e., mental processes that enable us to plan, focus attention, remember instructions). Parents rate items (e.g., "does not think before doing") on a three-point scale ranging from 1 (never) to 3 (often).

CBCL is a checklist filled in by the parent/legal guardian and aims to identify potential difficulties in behavioural function. The items are rated in a three-point scale (not true, somewhat or sometimes true, and very true or often true).

This test evaluates cognitive function. It consists of 15 subtests which are being administered via words, matrices, figures, objects, numbers.

Similarly, with WPPSI, WISC evaluates also cognitive function. The objectives of the test are very much alike with WPPSI-III, but this test targets children of older age. The version of this test will be the latest one available in the language of the clinical partners.

This test will be applied to measure the visual-perceptual function. It is a motor-free and individually administered test to evaluate the comprehensive visual perceptual functions for individuals aged 5-21 years. The TVPS-4 comprises 7 tests: visual discrimination, visual memory, spatial relationship, form constancy, sequential memory, visual figure- ground, and visual closure. The TVPS-4 has excellent reliability and concurrent validity with other similar tests.

MACS classifies the child's ability from 4 to 18 years old to handle objects in daily activities on one of 5 levels (level I: greater ability, level V: less ability). It is expected that all selected children for this study will be classified in MACS levels I to III: MACS level I (able to handle objects easily and successfully), level II (able to handle most objects but with somewhat reduced quality and/or speed of achievement so that alternate ways of performance might be used) or level III (handles objects with difficulty; needs help to prepare and/or modify activities).

The HFCS assesses UpL function of the impaired hand (ranging from 'does not use', level 0 to 'spontaneous use, complete', level 8) in children with UCP. The level of the child is typically agreed with caregivers.

Classifies the bimanual fine motor function in children with CP from 3 to 18 years old. It is a classification of the hand function in children with CP on a five-level scale, whereby level I describes the best and level V the most limited function. The BFMF also offers the possibility to classify the capacity of the two hands separately (figure 19), in contrast to MACS (classifying the performance of both hands together). The classification levels could be determined from short video recordings (< 5 minutes) of three fine motor tasks regardless of bimanual fine motor ability, making the BFMF 2 a feasible classification of fine motor capacity.

This questionnaire measures the manual abilities of children with CP (6-15 years old), with a particular reference to the independence in achieving some goals of everyday life, exploring if some activities are easily performed, if they present some difficulties or if they are impossible. It can be answered by parents or children and it requires 10 minutes.

The performance of the affected hand-use experience will be assessed with CHEQ. It is designed to measure children's own experiences when using the affected hand in common daily life activities requiring use of both hands. CHEQ is a computer-adaptive online questionnaire consisting of 27 items for children from 6 to 18 years old, and 21 items for the new version for children from 3 to 8 years old, available free of charge via the website (www.cheq.se). Three scales are used to measure the grasp efficacy when both hands are involved, time utilization when performing the activity compared with peers, and experience of feeling bothered while performing the activities independently.

It is a newly developed, parent-report measure for children aged 5 to 17 years that will evaluate the participation and environment of the child across three settings: home, school, and community (Coster et al., 2012). The PEM-CY examines the extent to which young people participate in important activity areas within home, school and community environments, and the extent to which features of these environments are perceived to support or challenge the young person's participation.

Quality of life will be measured using a condition specific measure, the CPQOL-Child parent report, or for children 9 years or age or older, the CPQOL-Teen (Davis et al., 2009). The CPQOL measures 7 broad domains of quality of life: social wellbeing and acceptance, functioning, participation, physical health, emotional wellbeing, access to services, pain, impact of disability and family health. The answers of the parent and/or of the teenager is on a 9 points Likert scale, expressing the feeling (as the degree of happyness) related to each question.

The Edinburgh Handedness Inventory (Oldfield et al, 1971) is a measurement scale used to assess the dominance of a person's right or left hand in everyday activities, sometimes referred to as laterality. The inventory can be used by an observer assessing the person, or by a person self-reporting hand use. The EHI is a simple quantitative method of assessing handedness, composed of 10 items (e.g. writing,drawing, throwing, using scissors). Handedness is calculated based on activities mainly done with right or left hand: it is the ratio between the difference of the two values divided by their sum, expressed as a percentage. It can range from - 100 (left-handed) to + 100 (right-handed). Only participants of TD group will be tested with EHI.

The DCDQ is a brief parent questionnaire designed to screen for coordination disorders in children, aged 5 to 15 years. Parents are asked to compare their child's motor performance to that of his/her peers using a 5 point Likert scale. It provides a standard method to measure a child's coordination in everyday, functional activities. The internal consistency of the DCDQ is high and the results from discriminant function analyses were appropriately strong for a screening tool (Wilson et al, 2000). Only participants of TD group will be tested with DCDQ

Personalized surveys will be administered and will be addressed at all children (both with UCP and with typical development), their parents and healthcare professionals. The survey will be administered in a different moment from other surveys and questionnaires, in that way the intestigators will allow respondents to not be overloaded with other batteries of questions to improve the quality of answers.

Independently to each other, if possible, both parents should answer their personalized questionnaire.

The already available brain images of children with UCP, commonly acquired for clinical diagnosis, will be collected. The images will be scored by expert raters by means of semi-quantitative validated scales called MRI Fiori scale, specifically developed for children with CP. This valid and reliable scale enables the quantification of severity of the brain lesion based on its structural MRI appearance (Fiori et al, 2013; Scheck et al, 2014). Moreover, the images will be de-identified and transferred to CSIRO/UQ in Australia and then will be analysed using automated software, producing quantitative measures of volume and cortical shape, and analysed using statistical regression.

On each wrist, a wristband with a tracker (ARYS™ pro trackers) will be worn during the AHA assessment and then for 14 days. These trackers record arm activity, and they provide the activity sum for each day. All the children enrolled (both children with UCP and TD) will be asked to wear the trackers every day for the whole day, except for night-time. During the night, the tracker shall be placed on the charger for recharging. At the end of the period of recording parents will have to place the sensors inside a box (previously received during the assessment) and they will be contacted by a member of the research staff to organize the collection of the material.