Brainwave Study of Nonverbal Patients Finds No Change Between Known, Unknown Names

Nonverbal patients with Angelman syndrome do not necessarily differentiate between known names — their own or those of others close to them — and unfamiliar names, as assessed through measurements of brain responses, a study suggests.

The study, “Social–emotional processing in nonverbal individuals with Angelman syndrome: evidence from brain responses to known and novel names,” was published in the Journal of Intellectual Disability Research.

The combination of intellectual, communication, and motor deficits in patients with Angelman syndrome reduces the feasibility of standardized behavioral measures.

Assessing electrical brain activity is an alternative approach to evaluate social information processing in these patients, although the link between electroencephalography parameters and behavioral or cognitive characteristics of Angelman syndrome is unknown.

More detailed information may be obtained with cortical event-related potentials (ERPs) — the measured brain response that can be directly induced with specific sensory, cognitive, or motor events.

In this study, researchers evaluated the extent of social-emotional processing in Angelman syndrome using auditory ERPs during passive exposure to spoken stimuli. This approach does not require active attention and avoids issues related to impaired comprehension of the task.

Specifically, the researchers used patients’ responses to their own names, which develops early in life and elicits a specific neural response in adults. However, individuals with developmental disabilities and social difficulties, as well as nonverbal children with Rett syndrome, have shown a lack of consistent response to their own names. As a result, researchers believe spoken names are an optimal stimulus to examine social-emotional processing in Angelman patients.

The study included 13 nonverbal patients with the Angelman deletion subtype, which is the most common and severe type. The researchers examined the patients’ responses to their own names as well as those unfamiliar to them. Testing both their own (and those of a close relative or friend) and unfamiliar names enabled the assessment of “spontaneous auditory attention to and processing of complex, socially relevant information,” they wrote.

Each name was presented 32 times in between 96 unique names of strangers. The task included 192 trials and lasted approximately 12 minutes. A parent or guardian and a researcher were present in the testing room to monitor the patients’ behavior. A TV show presented without sound was used as visual distractor.

Data of two participants were later excluded due to an insufficient number of good quality trials. The final group of 11 patients included seven males with a mean age of 15.1 years (range 4-45 years).

Caregivers completed the Parent/Caregiver Rating Form of the Vineland Adaptive Behavior Scales-3 (VABS-3), focusing on communication and socialization domains. Families of two participants did not return the VABS3 questionnaires. The nine patients with available data showed higher scores in the socialization domain than in communication.

The results revealed that, unlike typical children and adults, overall analysis did not show different neural responses between known and unknown names in Angelman patients.

According to the researchers, this result is in line with the higher incidence of autism symptoms in Angelman, although they cautioned that the task may have been too complex and that the number of participants was small.

However, better discrimination of a repeated stranger name from unknown names correlated with better functioning in communication and socialization. Also, more pronounced discrimination between known and unknown names was linked with better interpersonal relationships and the ability to receive and understand a message.

“Consequently, future interventions aimed at improving communication abilities in persons with AS may want to consider responses to own name as one of the early treatment targets,” the researchers wrote.