Can Tics Occur During Sleep?
Yes, tics can and do persist during sleep in individuals with Tourette syndrome and chronic tic disorders, though they are significantly reduced in both frequency and intensity compared to wakefulness. 1, 2
Evidence for Tic Persistence During Sleep
Polysomnography studies have definitively confirmed that tics persist during both REM and NREM sleep stages in patients with Tourette syndrome. 1 This finding directly contradicts older literature that suggested tics completely disappear during sleep. 3
The key distinction is that tics are attenuated during sleep, not eliminated. 1, 4 Research demonstrates:
- Tics occur during sleep but with reduced frequency and intensity compared to wakefulness 4
- Movements consistent with tics are documented during both REM and NREM sleep phases 1
- Objective cough recording has shown that cough tics can occur during sleep in patients with presumed tic disorders 3
Neural Mechanism of Sleep-Related Tic Reduction
Animal model research reveals a sophisticated dissociation between tic generation and tic expression during the sleep-wake cycle. 4 The neural correlates of tic generation (LFP spikes) persist during sleep at similar rates as wakefulness, but the behavioral expression is suppressed because local striatal neural activity becomes less entrained to these signals during sleep. 4 This explains why tics are reduced but not eliminated during sleep.
Clinical Implications and Sleep Disturbances
Patients with Tourette syndrome experience multiple sleep-related problems beyond the persistence of tics:
- Decreased total sleep time and lower sleep efficiency are the most consistent polysomnographic findings 1
- Elevated arousal index indicating fragmented sleep 1
- Increased sleep onset latency (difficulty falling asleep) 2
- Sleep onset and sleep maintenance insomnia are common complaints 1
- Periodic limb movements during sleep (PLMS) occur frequently 2
- Excessive daytime sleepiness likely secondary to underlying sleep disruption 1, 2
Important Diagnostic Considerations
A critical pitfall: The outdated teaching that "psychogenic cough" or "habit cough" does not occur at night has been disproven. 3 This characteristic was never prospectively validated and should not be used to exclude tic disorders. 3 In fact, objective recordings have demonstrated that cough tics can occur during sleep. 3
When evaluating chronic cough in children, tic disorders and Tourette syndrome must be ruled out before diagnosing habit cough or psychogenic cough. 3 The presence or absence of nighttime symptoms is not diagnostically reliable. 3
Impact of Comorbidities
Sleep problems are significantly worse in patients with comorbid ADHD, which affects 50-75% of children with Tourette syndrome. 5, 2 The combination of Tourette syndrome and ADHD cumulatively worsens sleep findings. 1 Children with co-occurring anxiety are also at particularly high risk for sleep difficulties. 6
Treatment Considerations
Treating the underlying Tourette syndrome is essential for improving sleep-related manifestations. 1 However, clinicians must recognize that many medications used to treat tics and comorbid disorders can themselves contribute to sleep problems. 2 This creates a complex clinical scenario requiring careful medication selection and monitoring.
Sleep difficulties are reported in approximately 80% of Tourette syndrome patients, with estimates ranging from 9.7% to 80.4% depending on the study methodology. 6, 7 This high prevalence underscores the importance of routinely screening for and addressing sleep problems in this population.