Facilitory paratonia and frontal lobe functioning

To learn if paratonia predicts frontal cognitive impairments.

Paratonia, an alteration of tone to passive movement, can be divided into oppositional paratonia ("gegenhalten," "paratonic rigidity") and facilitory paratonia. Although paratonia has been thought to be induced by frontal lobe dysfunction, previous studies suggest that paratonia does not correlate with cognitive impairment. However, only oppositional paratonia has been studied in this manner, and in these studies only the presence or absence of paratonia was assessed instead of a quantitative scale. Facilitory paratonia has not been studied for its relation to cognitive function.

Twenty-five patients evaluated for degenerative dementia were assessed on semiquantitative 5-point scales for paratonia by two independent raters. A quantifiable test--the modified Kral procedure--which assesses continued movement by the patient after cessation of passive movement was also administered for comparison with facilitory paratonia. To assess frontal lobe function, subjects were tested for echopraxia, distractibility, and word fluency. To screen for other cognitive defects, subjects were given the Mini-Mental State Examination (MMSE).

The modified Kral procedure strongly correlated with subjective rating of facilitory paratonia. This correlation was significantly stronger than the correlation with oppositional paratonia. The modified Kral procedure was also highly predictive of echopraxia, but was less predictive of other frontal lobe tests. Facilitory paratonia, oppositional paratonia, and the modified Kral procedure each strongly predicted scores on the MMSE.

Both facilitory and oppositional paratonia strongly predict general cognitive performance. The modified Kral procedure is a reliable indicator of facilitory paratonia and a predictor of impaired performance on frontal lobe tests.