What describes Periodic Limb Movements?

The correct choice explains that periodic limb movements are indeed associated with daytime sleepiness, and individuals often remain unaware of these movements taking place during sleep. This phenomenon is typically observed in conditions such as Restless Legs Syndrome or sleep-related movement disorders. The movements can disrupt sleep, leading to feelings of tiredness and sleepiness during the day, although the person is often oblivious to the fact that these movements occurred while they slept.

The other options do not accurately characterize periodic limb movements. For instance, an inability to recall movements upon waking is more related to certain sleep disorders or parasomnias, but it does not define periodic limb movements specifically. Muscle contractions can occur in both upper and lower limbs, so restricting the description to upper limbs is misleading. Additionally, while periodic limb movements may happen in various sleep stages, they do not primarily occur during the early stages of sleep; instead, they are often associated with lighter sleep as well as transitioning between sleep stages.