Digital archive of theses discussed at the University of Pisa


Thesis etd-05192015-152841

Thesis type
Tesi di specializzazione (5 anni)
Thesis title
Typical development of action observation in infancy and implications for neuro-rehabilitation: two parallel randomised controlled trials.
Course of study
correlatore Dott. Guzzetta, Andrea
relatore Prof. Cioni, Giovanni
  • Early intervention
  • Early intervention
  • Early intervention
  • Asymmetric brain lesion
  • Asymmetric brain lesion
  • Asymmetric brain lesion
  • Action observation
  • Action observation
  • Action observation
Graduation session start date
Release date
Asymmetric brain lesions around birth occur with an incidence of 1–2 every 1000 newborns. Most children develop in the first months some degree of neurological impairment of the limbs contralateral to the damaged hemisphere (Unilateral Cerebral Palsy). Recent studies demonstrate that the observation of motor actions can help rehabilitation by activating the so called “mirror neuron system”, which matches observed and performed actions. New evidence suggests that this mechanism is already present in infants, but little is known about its role in motor system development and brain reorganization following damage.
The main aims of this work are: I) reviewing current knowledge on the presence, characterization and timing of the neural correlates of action observation in human infants as well as on the theoretical neural underpinnings for exploiting this approach in early intervention; II) testing the effects of a novel training protocol based on Action Observation on prompting development of manual skills in typically developing infants and in infants with unilateral brain injury.
The research program includes two parallel randomized controlled trials, sharing the same methodology in terms of intervention and outcome measures.
The first trial was carried out in a population of typical development infants (TDI); the second one in a population of infants with asymmetrical brain lesions (aBI). Infants within each cohort were randomized to receive either Action Observation training (AOT), consisting of performing a series of slow grasping of a toy by the caregivers, or Toy Observation training (TOT), where a simple toy was presented without any action upon it; every training lasted 4 weeks, starting at 9 weeks post-term.
A number of measurements were assessed to evaluate the outcome. In this thesis, we focused on the assessment of manual skills, measured by a new scale, the Hand Assessment for Infants (HAI), for evaluating manual ability after training at 14, 16 and 18 weeks post-term. To assess more long-term effects, HAI was performed also at 6 months post-term.
In TDI, no significant differences were found between those receiving AOT and TOT. However, when comparing the two groups with an age-matched cohort of infants with typical development, who did not receive any training, significant differences were found in favor of those who received a training (either TOT or AOT) at 16 weeks and 18 weeks post-term.
In the cohort of aBI infants, no significant differences emerged in Sum bimanual score, Sum potentially affected limb score and asymmetry index values in infants receiving AOT compared to those receiving TOT.
These first results outline how early intervention could prompt, in healthy infants, motor system development in early life, priming infants to reaching and grasping before they are fully established. Both AOT and TOT seem to have a comparable effect, probably related to the early and intensive stimulation of visual attention delivered in both trainings, which may improve subsequent visual-motor matching useful for development of manual skills.
Also in infants with asymmetric brain lesions, occurred in prenatal or perinatal period, early training based on action observation seems equivalent in supporting adaptive processes of brain plasticity compared to a training stimulating only visual attention. This might suggest that other factors, such as attention to moving object and visual engagement with the care-givers, may play an important role in enhancing the development of manual skills after early brain injury.