While periodic limb movements during sleep (PLMS) and restless leg syndrome (RLS) are well known in Parkinson’s disease, similar movements during wakefulness are not as well described.
A recent case report described, for the first time, episodes of “periodic limb movements during wakefulness” in patients with Parkinson’s disease (PD).
While periodic limb movements during sleep (PLMS) and restless leg syndrome (RLS) are well known in PD, similar movements during wakefulness are not as well described, creating a challenge for the diagnosis.
Write in the journal Movement disordersthe authors stated that periodic limb movements during wakefulness, or PLMA, is a wear-and-tear phenomenon in PD and could be classified as low-dose dyskinesia because all 4 patients described in the report responded to treatment dopaminergic.
The involuntary movements of PLMA share similar characteristics with the movements observed during sleep, although they most often occur in the transition phase from falling asleep at night or during daytime rest.
Criteria established by the International Restless Legs Syndrome Study Group (IRLSSG) include the presence of PLMA as a motor sign that supports the diagnosis of RLS.
Most people with PLMA have brief leg and foot movements lasting between 1.5 and 2.5 seconds, usually marked by extension of the big toe or triple flexion at the ankle, knee and hip.
For the patients described in the report, the movements included:
- Episodic non-rhythmic jerky movements of the feet
- Dorsiflexion and plantarflexion of the ankle, sometimes accompanied by more gentle flexion of the knee and hip
- Toe movements
- Movement intervals ranged from 20 to 35 seconds
The researchers said they considered other explanations before arriving at PLMA.
“All four individuals had a good response to dopaminergic medications, which suggested a possible manifestation of attrition,” they wrote. Patients did not move voluntarily to relieve the discomfort that comes from RLS or akathisia in the off state.
They also ruled out levodopa-induced dyskinesia. Patients did not exhibit sustained, painful postures or repetitive, wider leg movements.
Idiopathic RLS has been proposed to arise from reduced levels of striatal D2 receptors, lower iron levels in the central nervous system, or peripheral factors, such as abnormal vascular flow in affected limbs; the authors noted that 3 of the 4 patients had associated axonal neuropathy, which has previously been described in association with RLS.
All 4 patients had a history of PLMS, with similar nocturnal movements.
The study had some limitations. The diagnosis of PLMS was objectively confirmed in 1 patient through the use of polysomnography. The authors also did not perform an immobilization test, which has been proposed as a potential standard for grading and assessing the severity of PLMA. The diagnosis of PLMA was based on clinical observations and history, the authors said.
AlshimemerIS, DiLuca DG, Olszewska DA, et al. Periodic limb movements during wakefulness (PLMA) as a manifestation of exhaustion in Parkinson’s disease: a case series and review of the literature. Disorder Mov. Published online May 12, 2022. doi:10.1002/mdc3.13487