What our current study seeks to update / inform:

1. Voltage Gated Ion Channels and Sleep. The Journal of Membrane Biology (Volume 257, Issues 5–6, Pages 269–280) published December 2024, with online publication on October 1, 2024. A review of Ca²⁺, Na⁺, and K⁺ channel roles in sleep regulation across species; links dysfunction to sleep disorders and potential therapies. 10.1007/s00232-024-00325-0  Evidence shows Nav, K⁺, and especially Cav3.x channels regulate sleep-onset oscillations via thalamocortical circuits; disruption fragments NREM and alters transitions, supporting SOVM’s channelopathy-driven oscillation–vasomotor mismatch model. Serves as the primary citation for why voltage-gated ion channels are central to sleep onset stability. Supports the genetics link between your cohort’s variants and altered oscillatory gating. Provides a mechanistic bridge to the vasomotor dysregulation component —integrated from the other neurovascular literature.Handbook of Clinical Neurology, Vol. 99 (3rd series) Sleep Disorders, Part 2

   P. Montagna and S. Chokroverty, Editors

   2011 Elsevier B.V. Chapter 54

2. Isolated motor phenomena and symptoms of sleep”. R. VETRUGNO, F. PROVINI, AND P. MONTAGNA* Department of Neurological Sciences, University of Bologna Medical School, Bologna, Italy https://cdn2.hubspot.net/hubfs/4256583/Chapter-54Isolated-motor-phenomena-and-symptoms-of-sleep_2011_Handbook-of-Clinical-Neurology.pdf

Note on K-Complexes: in 2 of our study cohort members sleep studies, the jerks seen were time-locked to K-complexes. According to Montagna (2011), hypnic jerks are often associated with K-complexes and vertex sharp waves. In clinical sleep studies, these are often dismissed as 'normal arousals,' but in our cohort, they align with disruptive myoclonic jerks and support the interpretation that these are pathological rather than benign variants.

Article Summary: Isolated Motor Phenomena and Symptoms of Sleep

Physiological fragmentary hypnic myoclonus (PFHM): “The muscle discharges … appear as isolated or bursts of motor unit action potentials with or without visible movement.”

Excessive fragmentary hypnic myoclonus (EFHM): “Small myoclonic twitches and fasciculations are present throughout sleep … without gross displacements across a joint space.” EFHM twitches are absent during wakefulness and show no cortical potentials related to the twitches, meaning they can be real motor discharges but remain sub-threshold for large visible jerks.

Overview

Sleep is normally a state of sensory and motor inhibition, but many isolated motor events occur. Some are physiological variants, others are borderline or pathological, and many lack a clear classification in the ICSD-2.

1. Physiological & Excessive Fragmentary Hypnic Myoclonus (PFHM, EFHM)

PFHM: brief, arrhythmic, asynchronous twitches in face or limbs, mostly in stage 1 NREM and REM. Origin likely reticulospinal pathways bypassing REM inhibition. Considered benign. EFHM: pathological enhancement with small twitches throughout sleep, linked to insomnia, apnea, RLS, and other disorders. Often overlooked, but may fragment sleep.

2. Hypnic Jerks (Sleep Starts)

Classic abrupt jerks of limbs, neck, or trunk at sleep onset. Often linked with sensory phenomena (falling, electric shock, fear). EEG shows K-complexes and vertex sharp waves. Usually benign but can cause insomnia when frequent.

3. Propriospinal Myoclonus (PSM)

Jerks spreading up and down the spinal cord, especially at wake–sleep transition. No cortical EEG correlates. Can prevent sleep onset. Sometimes idiopathic or drug/trauma-related. Clonazepam may reduce severity.

4. Benign Sleep Myoclonus of Infancy

Jerks begin in the first month of life, resolve by 3–12 months. Normal EEG, stop on waking. No later epilepsy risk. Likely due to benign brainstem or serotonergic immaturity.

5. Nocturnal Leg Cramps

Painful involuntary calf contractions at night. Common in elderly, linked to electrolyte imbalance, vascular disease, or medications. Different from RLS. Quinine works but risky.

6. Rhythmic Movement Disorders (RMD)

Repetitive headbanging, body rocking, or foot tremor, especially in children. Often resolves but can persist. Variants: hypnagogic foot tremor, alternating leg muscle activation.

7. Other Isolated Sleep Phenomena

Includes sleeptalking, catathrenia (groaning), laryngospasm, choking/swallowing syndromes,

neurogenic tachypnea, night sweats, nocturnal panic attacks, sleep-related hallucinations, sleep paralysis, and status dissociatus. Most are benign but may mimic epilepsy or cause distre