Spontaneous eyeblink rate in focal cerebrovascular lesions.

BACKGROUND: The involvement of different brain areas in spontaneous eyeblink rate control is largely unknown. METHODS: Spontaneous eyeblink rate was assessed in 211 consecutive acute stroke patients within two days after symptom onset and was correlated with infarction location as well as with other parameters such as the presence of hemineglect or significant small vessel disease in MRI or CT scans. Blink rates were measured in two conditions: (1) during a trivial conversation requiring no cognitive effort and (2) during mental arithmetic. RESULTS: Patients and healthy controls displayed similar average blink rates at rest (19.1 and 17.3 blinks/min, respectively) and during mental arithmetic (22.6 and 20.2 blinks/min, respectively). The latter condition reliably increased blinking frequency in both patients and control subjects. The subgroups of patients with frontal, frontoparietal and frontotemporal infarctions exhibited a significantly higher blink rate modulation, expressed as an increased relative difference of blinking at rest compared with blinking during mental arithmetic. CONCLUSION: As a whole, patients with acute cerebrovascular disease do not show changes in blink rate. Subjects with frontal infarcts, however, systematically increase their blink rates during cognitive effort, most probably due to a lack of frontal inhibitory control on blinking modulation.