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Neurology. 1999 Oct 12;53(6):1201-5.

Changes in excitability of motor cortical circuitry in primary restless legs syndrome.

Author information

1
Department of Neurology, University of Utah, Salt Lake City 84132, USA.

Abstract

OBJECTIVE:

To investigate the excitability of segmental and suprasegmental systems in patients with primary restless legs syndrome (pRLS) by measuring the cortical silent period (C-SP) and the peripheral silent period (P-SP).

BACKGROUND:

There is some evidence that RLS may be the motor manifestation of normal CNS periodicity that becomes disinhibited under certain conditions. The mechanism of this disinhibition is unclear.

DESIGN/METHODS:

Ten patients with pRLS and 10 normal age-matched subjects were studied. The mixed nerve P-SP produced by electrical stimulation of the median and common peroneal nerves was recorded during maximal contraction of the abductor pollicis brevis (APB) and tibialis anterior (TA) muscles. The C-SP produced by a single magnetic shock to motor cortex at 150% of resting threshold was also measured during maximal contraction of the APB and TA muscles. The average of 5 to 10 trials at each site was obtained and compared using Student's t-test.

RESULTS:

Resting central motor threshold was not significantly different between pRLS patients and the control group. The average duration of the C-SP was shorter in the APB (74.5+/-37.7 versus 129.56+/-35.95 msec, p<0.05) and TA (66.81+/-25.63 versus 136.1+/-40.35 msec, p<0.05) in patients with pRLS. The P-SP duration, however, was not significantly different between two groups in either limb.

CONCLUSION:

The supraspinal inhibitory system is impaired in pRLS.

PMID:
10522873
[Indexed for MEDLINE]

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