Selective attentional deficit in essential tremor: Evidence from the attention network test

• ET patients displayed a global delay in RTs, unrelated to disease severity/duration.
• ET patients displayed a worse alerting and executive network efficiencies.
• The orienting network seemed to be preserved in ET patients.
• These selective attentional deficits point to a more complex clinical picture.

IntroductionThe traditional view of essential tremor (ET) as a monosymptomatic and benign disorder has been reconsidered after patients with ET have been shown to experience cognitive deficits that are also related to attention. The Attention Network Test (ANT) is a rapid, widely used test to measure the efficiency of three attentional networks, i.e. alerting, orienting and executive, by evaluating reaction times (RTs) in response to visual stimuli. The aim of this study was to investigate attentional functioning in ET patients by means of the ANT.Methods21 non-demented patients with ET and 21 age- and sex-matched healthy controls performed the ANT.ResultsRT was significantly longer in ET patients than in controls (p < 0.001). Moreover, a significant difference in alerting and executive efficiency (p = 0.003 and p = 0.01 respectively) was found between groups, while the difference in the orienting efficiency only bordered on significance.ConclusionOur results point to a difficulty in the alerting and executive domains of attention in ET patients, probably owing to a dysfunction in the cerebello-thalamo-cortical loop. These selective attentional deficits are not related to clinical motor symptoms, contributing to shed further light on the clinical picture of ET.