Voluntary, spontaneous and reflex blinking in PSP

As we’ve heard, blink rate is “profoundly sparse in PSP.” This recently-published Italian research looks at 11 patients with probable PSP and records eyelid movements during three types of blinking — voluntary, spontaneous and reflex blinking. Blinking was found to be abnormal in all three types.

Brain. 2008 Nov 29. [Epub ahead of print]

Voluntary, spontaneous and reflex blinking in patients with clinically probable progressive supranuclear palsy.

Bologna M, Agostino R, Gregori B, Belvisi D, Ottaviani D, Colosimo C, Fabbrini G, Berardelli A.
Department of Neurological Sciences and Neuromed Institute, Sapienza, University of Rome, Italy.

Patients with progressive supranuclear palsy (PSP) often have blinking abnormalities.

In this study we examined the kinematic features of voluntary, spontaneous and reflex blinking in 11 patients with PSP and healthy control subjects. Patients were asked to blink voluntarily as fast as possible; spontaneous blinking was recorded during two 60 s rest periods; reflex blinking was evoked by electrical stimulation of the supraorbital nerve. Eyelid movements were recorded with the SMART analyzer motion system.

During voluntary blinking the closing and opening phases lasted longer in patients than in healthy subjects. Furthermore, the peak velocity of the closing phase of voluntary blinking was lower in patients than healthy subjects.

During spontaneous blinking the blink rate was markedly lower in patients than in control subjects. Patient’s recordings also showed kinematic abnormalities of spontaneous (reduced peak velocity of both closing and opening phases) and reflex (reduced peak velocity and increased duration of the opening phase) blinking.

Recordings during reflex blinking disclosed an enhanced excitability of the interneuronal pool mediating the closing and opening blink phases.

Finally, the pause, a neurophysiological marker of the switching processes between the closing and opening phases, was prolonged in all the three types of blinking.

The abnormal kinematic variables correlated with patients’ clinical and kinematic features. Abnormal voluntary, spontaneous and reflex blinking in patients with PSP reflects the widespread cortical, subcortical and brainstem degeneration related to this disease.

PubMed ID#: 19043083 (see pubmed.gov for abstract only)

From TheFreeDictionary:
kinematics – dealing with the study of the motion of a body