Behavioral Tests Useful in Assessing Memory and Motor Abilities in Angelman Children, Study Suggests

Behavioral tests based on how well a child performs specific tasks may be promising tools for evaluating memory and motor abilities in those with Angelman syndrome (AS) and be of particular use in clinical trials, a pilot study reports.

The study, “Using Behavioral Approaches to Assess Memory, Imitation and Motor Performance in Children with Angelman Syndrome: Results of a Pilot Study,” was published in the journal Developmental Neurorehabilitation.

Angelman syndrome is a rare, inherited disease that affects the nervous system and is characterized by severe intellectual, developmental, and physical disabilities.

Selecting ways of assessing Angelman children is specially challenging, given problems with cognition, tremors, uncoordinated movements (ataxia), short attention spans, seizures, and absent or minimal speech that can mark the disease.

The need exists for additional instruments to measure learning, motor and memory skills. And these measures need be developmentally appropriate, capable of yielding objective and quantifiable data, and sensitive to small changes in performance, the study noted.

Bearing this in mind, Jane Summers, PhD, a clinical psychologist at Hospital for Sick Children in Canada, developed a behavioral test that scores how well children perform on tasks specifically selected to assess memory, imitate motor actions, and motor performance.

According to the researcher, these functions and their outcomes are likely to be the focus of upcoming clinical trials into ways of treating these children.

Summers developed the assessments based on available literature on infant memory, studies of motor imitation in children with autism and severe intellectual disabilities, and previous applied behavior analysis (ABA) studies involving children with Angelman syndrome.

Three different tests — recall memory, imitation of motor actions, and motor performance — were performed on 12 children (ages ranging from 3 to 12) with Angelman syndrome at several time points over three months. Eleven of the children had the more severe disease form caused by a deletion in chromosome 15  (15q11-q13).

The study’s timeline included an initial period of pretesting (memory and imitation), followed by a period of training (for memory only) and assessments (memory, motor imitation and performance), where the child’s performance was scored.

Each session took place in children’s homes. Whenever possible, the child was seated at a table or otherwise in a chair or wheelchair.

For the memory tests, children were first taught two-step tasks (e.g., turning a cup over and flattening it with the hand) for several training runs, and then asked to repeat these tasks alone one hour, one day, one week, and one or two months later.

For the motor imitation assessment, target motor actions were first demonstrated to the child. After a brief pause, the child was given a chance to imitate the action. Actions included one- or two-handed, hands-to-face, or body-related actions (examples including holding hands out, tracing a line on a table with a finger, blowing a kiss).

Motor performance tests had a similar setup, but the tasks were timed (60 seconds) and intended to address fine motor coordination and manual dexterity. They included placing plastic pegs into holes, placing rubber eggs into separate compartments, dropping poker chips through a slot in a box, stacking plastic cups, and threading large wooden beads onto a dowel.

The results revealed that memory and motor performance tests rated moderate to excellent in terms of test-retest reliability — supporting the consistency of a given instrument. They also had excellent inter-rater reliability, referring to the degree to which different raters, or examiners, agree on estimates of the same behavior.

Unlike these two assessments, the motor imitation test showed poor test-retest reliability “indicating that children’s scores were not stable across time which limits the ability to detect real change,” the researcher wrote.

Motor performance scores were significantly correlated with a child’s age and raw scores for receptive language, expressive language, personal living, and fine motor of the Vineland-II scale, which  measures intellectual and developmental disabilities.

“The care needs of individuals with AS [Angelman syndrome] can place huge demands on their families and caregivers and for the individual with AS, lead to a lifetime of almost total dependency on others. The behavioral tests reported in this study require further development and evaluation but may show promise as outcome measures for clinical trials that have the goal of ameliorating, reversing or ideally preventing symptoms of AS,” the researcher concluded.