Managing Stimulus-Induced Drop Episodes (SIDEs)

One of the most unique and challenging aspects of Coffin-Lowry Syndrome (CLS) is the occurrence of Stimulus-Induced Drop Episodes (SIDEs). For a parent, watching these episodes can be frightening, but understanding their nature is the first step toward creating a safer environment for your child ^[1][2]. Return to the Home Page.

What are SIDEs?

SIDEs are sudden, brief episodes where a person loses muscle tone and falls to the ground ^[3]. Unlike a typical fall, these are triggered by a sudden “startle” response ^[1].

• Triggers: The most common triggers are unexpected auditory stimuli (like a balloon popping or a door slamming) or tactile stimuli (like a sudden tap on the shoulder) ^[2][3].
• The Experience: During a SIDE, the person typically remains fully conscious. There is no “post-ictal” period (the confusion or sleepiness that follows a seizure), and the person can usually get back up almost immediately ^[3].
• Age of Onset: It is important to note that SIDEs usually do not present in infancy. They typically emerge in mid-childhood, most commonly between the ages of 5 to 10 years ^[4][3].

SIDEs vs. Epilepsy

It is critical to distinguish SIDEs from epilepsy (seizures). While both involve sudden movements or drops, they are biologically different ^[3].

• Brain Activity: Epileptic seizures are caused by abnormal electrical activity in the brain. In contrast, SIDEs are generally considered a non-epileptic movement disorder ^[3][4].
• EEG Findings: If a child has an EEG (electroencephalogram) during a SIDE, it typically does not show the “spikes” or “waves” associated with a seizure ^[3].
• Important Note: True epilepsy (including a subtle form called nonconvulsive status epilepticus) can occur in some individuals with CLS. Any change in the “flavor” or frequency of drops should be evaluated by a neurologist ^[3][5].

Management and Safety

Currently, there are no standardized, evidence-based pharmacological guidelines for treating SIDEs in CLS ^[6]. Management is highly individualized and focuses on two areas: medication and environment.

Medication Options

While not universal, some doctors may trial certain medications to reduce the severity of the startle response:

• Clonazepam or SSRIs: Sometimes used to help regulate anxiety and the startle reflex.
• Valproate: It is crucial to understand that anti-epileptic medications like Valproate are typically only effective if there is a suspicion of co-occurring true seizures. They do not generally cure the startle-reflex drops (SIDEs) themselves ^[7].

Practical Safety Strategies

Because medication is not always effective, environmental “startle-proofing” is the most empowering tool for caregivers:

1. Water Safety (CRITICAL): Because a drop attack causes a sudden, complete loss of muscle tone, experiencing a SIDE in a bathtub or swimming pool poses an extreme, immediate drowning hazard. Constant, ‘touch-distance’ supervision is absolutely mandatory during all water activities.
2. Minimize Triggers: Work with schools and caregivers to reduce sudden loud noises. For example, using “silent” bells or giving the child a 10-second warning before a scheduled loud event ^[3].
3. Protective Gear: For children with frequent drops, specialized protective headgear (helmets) can prevent head injuries during falls ^[8].
4. Strategic Seating: Use chairs with armrests or wheelchairs with straps during activities where a fall could be dangerous.
5. Educate Others: Ensure that teachers and peers understand that the drops are a physical reflex, not a “behavioral” choice or a medical emergency like a seizure.

By focusing on safety and trigger management, you can help your child navigate their daily life with more confidence and fewer injuries.