Abnormal blink reflex (BR) results mainly from the dysfunction of reticular brainstem pathways and is one of the features of degenerative brain disorders. We aimed to investigate whether patients with Wilson's disease (WD) have abnormal BR. This was a prospective, observational, single-center study. BR was assessed in accordance with generally accepted standards in 44 newly diagnosed treatment-naïve and 66 treated patients with WD. Any abnormal parameters in BR were observed in 45.5% treatment-naïve patients and 37.9% treated patients (p = 0.429). We also did not observe significant differences in BR parameters and frequency of abnormal findings between treated and treatment naïve patients. Abnormal findings in any of the BR parameters were more frequent in patients with neurological vs. non-neurological presentation (57.5 vs. 28.6%, p = 0.002), present vs. absent Kayser-Fleischer ring (73 vs. 21.5%, p < 0.001), and typical vs. no typical WD abnormalities in brain MRI (50% vs. 24.4%, p = 0.009). In addition, longer median R1 and R2 latencies, both ipsilateral and contralateral, were significantly more frequent in neurological than non-neurological WD patients, those with Kayser-Fleischer rings, and those with abnormal MRI findings typical of WD. Our results confirm frequent BR abnormalities in WD, which may be explained by the pathological influence of copper deposits in the circuit linking the basal ganglia, cerebellum and brainstem.

Spontaneous eye blink rate is modulated by task demands and internal state, and is demonstrated to reflect central dopamine activity. Also, spontaneous eye blinks are strategically timed around salient stimuli. This study investigates whether children with attention deficit hyperactivity disorder (ADHD) show reduced blink rates, blink modulation and blink timing, and whether this is influenced by stimulant medication. The electrooculogram was measured in 18 typically developing children, 16 children with ADHD off methylphenidate (Mph), and 16 children with ADHD on Mph during a rest period and during performance of a 60-min visual selective attention task. Blink rate and timing was extracted from the electrooculogram. No evidence was found for aberrant blink rate or blink modulation in children with ADHD off Mph. All groups increased blink rates from rest to task, and no group differences were found in blink rate during rest and task, or in the modulation of blink rate from rest to task. Time-on task resulted in a similar increase in blink rates in all three groups. Stimulant medication appeared not to influence blink rate and blink modulation, except that in the ADHD off Mph group the blink rate was enhanced only under conditions with performance feedback. All groups inhibited blinks before stimulus presentation and strategically timed their blinks after the stimulus. Children with ADHD off Mph showed reduced blink inhibition before the stimulus; however, given the low incidence (<1 % of the trials) and long latency this is not likely to impair their visual intake.