Attentional rather than sensory differences characterize auditory processing in Williams syndrome

Neurophysiological Correlates of Dynamic Beat Tracking in Individuals With Williams Syndrome

BACKGROUND

Williams syndrome (WS) is a neurodevelopmental disorder characterized by hypersociability, heightened auditory sensitivities, attention deficits, and strong musical interests despite differences in musical skills. Behavioral studies have reported that individuals with WS exhibit variable beat and rhythm perception skills.

METHODS

We sought to investigate the neural basis of beat tracking in individuals with WS using electroencephalography. Twenty-seven adults with WS and 16 age-matched, typically developing control subjects passively listened to musical rhythms with accents on either the first or second tone of the repeating pattern, leading to distinct beat percepts.

RESULTS

Consistent with the role of beta and gamma oscillations in rhythm processing, individuals with WS and typically developing control subjects showed strong evoked neural activity in both the beta (13-30 Hz) and gamma (31-55 Hz) frequency bands in response to beat onsets. This neural response was somewhat more distributed across the scalp for individuals with WS. Compared with typically developing control subjects, individuals with WS exhibited significantly greater amplitude of auditory evoked potentials (P1-N1-P2 complex) and modulations in evoked alpha (8-12 Hz) activity, reflective of sensory and attentional processes. Individuals with WS also exhibited markedly stable neural responses over the course of the experiment, and these responses were significantly more stable than those of control subjects.

CONCLUSIONS

These results provide neurophysiological evidence for dynamic beat tracking in WS and coincide with the atypical auditory phenotype and attentional difficulties seen in this population.

Abnormal auditory event-related potentials in Williams syndrome

Individuals with Williams Syndrome (WS) have specific auditory characteristics, including hypoacusis and hyperacusis, and music appreciation skills. Little is known about the functionality of the central auditory nervous system (CANS) for sound processing in WS. Thus, the objective of the present study was to evaluate the functionality of the CANS in individuals with WS, based on auditory event-related potentials, as far as cognitive and behavioral aspects are concerned. The study was carried out with 17 individuals, seven females and ten males, between seven and 17 years old, with WS, and 17 individuals with typical development matched by sex and chronological age to individuals with WS. None of these individuals had middle ear impairment or hearing loss. The subjects were evaluated for intelligence quotient, loudness discomfort level, and auditory event-related potentials with Tone Burst stimuli, on the oddball paradigm; the parents also answered the MTA-SNAP-IV questionnaire. Hyperacusis was found in six WS individuals and two individuals with typical development. In the present study, WS individuals present longer latency and reduced amplitude for P1, N1, N2 and P3 components. These results, suggesting a delay and hypoactive responses of the CANS in this syndrome, that cannot be related to the cognitive or behavioral aspects of these individuals, but it indicates a cortical immaturity to process acoustic stimuli.

Williams syndrome: recent advances in our understanding of cognitive, social and psychological functioning

PURPOSE OF REVIEW

Since the last review of Williams syndrome in Current Opinion (2001) there have been many advances in knowledge about the cognitive, social and psychological impairments that characterize the disorder. The present review focuses on current research in these areas.

RECENT FINDINGS

Williams syndrome is associated with a wide range of cognitive, linguistic, social and other difficulties. When young, these deficits may appear relatively mild - for example, many children are highly sociable and talkative - but with age the impact of these difficulties becomes more evident. Thus, inappropriate social behaviours can significantly increase the risk of social exclusion and vulnerability to abuse. Their superficially good speech can lead to educational and other services failing to understand the true extent of impairments or the need for specialist support. Mental health problems, especially related to anxiety, often become an increasing challenge from adolescence onwards.

SUMMARY

The core difficulties associated with Williams syndrome have a cascading effect on many areas of development over time. However, specialist provision is rare and intervention trials are almost nonexistent. Longitudinal research is needed to identify factors associated with cognitive, social and emotional problems and to develop more effective ways of minimizing and treating difficulties.