Cervical Spondylosis Triggered Rare Spinal Myoclonus and Involuntary Vocalizations; Endoscopic Surgery Resolved Symptoms Within 24 Hours

A 55-year-old man from southern China endured three years of ordinary neck pain before a sudden escalation over one month. Twice daily, 5- to 15-minute episodes brought hand tremors, involuntary muscle jerks, and spontaneous crying out.

A case report published March 31, 2026, in Frontiers in Surgery identified the cause as cervical spondylosis—age-related wear of the neck spine—rather than a brain disorder. Head imaging was normal. Surgeons determined that relieving pressure on the spinal cord eliminated both the jerks and vocal outbursts within 24 hours.

A team from two hospitals in Yulin, Guangxi, China, diagnosed propriospinal myoclonus, a rare movement disorder they described as an exceedingly uncommon complication of cervical spondylosis with limited reports involving vocalizations.

A Familiar Neck Problem With an Unfamiliar Twist

Cervical spondylosis is among the most common spinal conditions. The American Academy of Orthopaedic Surgeons reports that more than 85% of people over 60 have it, though many never notice symptoms while others mainly experience neck pain and stiffness.

When worn discs and bone spurs narrow the space around the spinal cord, the picture can worsen. Typical warning signs include arm, hand, and finger numbness or weakness, trouble walking, and loss of balance.

This patient showed multiple signs of cord involvement: dizziness, leg weakness, occasional abdominal discomfort, overactive reflexes in the limbs, upper-limb stiffness, clonus at the knees and ankles, and a positive Hoffmann’s sign indicating spinal cord compression. Muscle strength remained normal.

MRI and CT scans revealed bulging discs from C3/4 through C5/6, instability at C5, and severe cord compression sufficient to block normal spinal fluid flow.

When the Spinal Cord Starts Firing on Its Own

Myoclonus refers to sudden, brief, involuntary muscle jerks. Most people recognize the harmless hypnic jerk that occurs while drifting off to sleep. According to the National Institute of Neurological Disorders and Stroke, some forms originate not in the brain but in the spinal cord itself.

Propriospinal myoclonus is one such spinal variant. Jerks are thought to start at one cord level and travel through pathways linking spinal segments. It typically involves the trunk and often appears when lying down.

That pattern fit this man: episodes were worse before sleep, movements were mostly flexion, and he occasionally had hand clenching spasms and abdominal muscle jerking.

The authors proposed that long-term mechanical squeezing of the cervical cord damages small inhibitory nerve cells that normally keep a local “spinal segmental generator” in check. Without that brake, the circuit can fire autonomously.

As for the cries, the team offered a hypothesis rather than proof. Sudden contractions of abdominal and rib muscles may have forced air through the vocal cords, possibly alongside irritation of cord levels C3 to C5 where diaphragm-controlling neurons reside.

Endoscopic Surgery and a Fast Turnaround

After multiple rounds of conservative treatment elsewhere failed, surgeons performed an endoscopic anterior cervical discectomy and fusion spanning C3 to C6. Working through the front of the neck with a narrow scope, they removed protruding discs, cut through a posterior ligament, freed the spinal cord and nerve roots, and placed fusion cages between vertebrae.

Blood loss was about 50 milliliters. The patient was up and walking with a brace the day after surgery, and both the myoclonus and vocalizations stopped within 24 hours.

His mJOA spinal cord score rose from 12 before surgery to 16 at one month and 18, the top of the scale, at six months. Neck pain fell from 6 to 1 on a 10-point scale. At 12 months, walking was normal, symptoms had not returned, and he had resumed manual labor.

The rapid recovery supports compression as the driver. The authors noted that previous surgically treated cases used open surgery, describing theirs as the first reported endoscopic technique for the condition.

A Case Easily Mistaken for Something Else

The broader lesson is diagnostic. Sudden jerks combined with involuntary noises can resemble epilepsy or a psychological condition, and this disorder is often misdiagnosed as exactly that.

The opposite mistake is also common. A 2010 study in the Journal of Neurology examined 35 consecutive patients referred for possible propriospinal myoclonus and concluded that 34 had features pointing to a functional, or psychogenic, origin, with only one confirmed organic cause linked to ciprofloxacin.

That history makes this report’s main weakness important. The authors acknowledged that EEG and EMG testing, which can help separate spinal myoclonus from functional movements, were unavailable. The diagnosis rested on clinical observation and established criteria, with outcomes relying partly on patient reports.

It is also a single case and does not show that people with neck arthritis face a meaningful risk of these symptoms.

Still, the report carries a practical message for clinicians: when cervical spondylosis appears with unusual symptoms such as vocalizations, spinal myoclonus belongs on the differential. Anyone with new, unexplained jerking movements, hand weakness, or trouble walking should seek evaluation from a qualified clinician.

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