Direct Assessment of Aggressive Behavior in Low Functioning Autism: A Cohort Observational Study.

Background: Aggressive behavior (AB) refers to directed acts of aggression that can potentially harm, or already have harmed others, themselves or destroyed property. Parents frequently report that aggression in their child is more distressing than poor adaptive skills. Most studies on this topic rely on the use of specific scales like the Children’s Scale for Hostility and Aggression.

Objectives: The aim of the study is to quantify the expression of AB in a cohort of subjects with ASD admitted to a Rehabilitation Institute by means of direct careful observation of their behavior for 28 consecutive days. To our knowledge, this is the first study to explore directly observed AB and to correlate its intensity with autism severity.

Methods: Twenty consecutive children and adolescents (mean age 15.15 yrs; range: 5-19; 19 males) with autism, admitted to our Institute took part to this observational study. The ASD subjects were diagnosed according to the DSM V criteria, then confirmed through ADOS 2. Ten expert female educators continuously monitored the subjects for 28 consecutive days recording the occurrence of the following AB: aggression of peers or educators by punching, kicking, boosts, biting, spitting, scratching; or self-inflicted injury with bites, scratches, punches to body or to head. The total sum of aggression and self-inflicted injury acts during the four weeks were taken as biomarkers of AB in the specific subject. These values were correlated with the ADOS total score and with the number of stereotypies patterns, derived from a video catalogue developed for a parallel specific study.

Results:

Five out of 20 subjects (mean age 14.8 ) showed zero aggression acts during the study period. Their mean ADOS score was 21.2. Fifteen subjects showed from 2 to 31 acts of aggression (mean= 7.46 ) during the study period. Their mean ADOS score was 19.06. Eleven out of twenty subjects showed zero self-injury acts during the study period. Their mean ADOS score was 18.09. Nine subjects showed from 1 to 37 acts of self-injury (mean = 13.22) during the study period. Their mean ADOS score was 21.44.The Pearson correlation index between the four-week number of aggression acts and ADOS scores and between four-week number of self-injury acts and ADOS scores resulted in 0.06 (NS) and 0.80 ( p =0.009) respectively. In the same subgroups, the Pearson correlation index between the total number of aggression acts and the number of stereotypies patterns, and between the total number of self-injury acts and number of stereotypies patterns resulted in -0.24 ( NS ) and 0.74 ( P = 0.001) respectively.

Conclusions: Our pilot study suggest that while self-injury behavior is highly correlated to Autism severity and stereotypies intensity, aggression per se is not at all correlated to both autism severity and stereotypies intensity. Future studies with direct observation on larger samples are needed to explain the nature of this difference.