Involuntary blinking rate is decreased in idiopathic Parkinson’s disease (and may be improved by dopaminergic therapy) and progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome). In contrast, blink rate is normal in multiple system atrophy and dopa-responsive dystonia, and increased in schizophrenia and postencephalitic parkinsonism. These disparate observations are not easily reconciled with the suggestion that blinking might be a marker of central dopaminergic activity.
Loss of spontaneous blinking has been reported in Balint’s syndrome. In patients with impaired consciousness, the presence of involuntary blinking implies an intact pontine reticular formation; absence suggests structural or metabolic dysfunction of the reticular formation. Blinking decreases in coma. Functional disorders may be accompanied by an increase in blinking.