Tics are irregular, uncontrollable, unwanted, and repetitive movements of muscles that can occur in any part of the body. Movements of the limbs and other body parts are known as motor tics. Involuntary repetitive sounds, such as grunting, sniffing, or throat clearing, are called vocal tics. Tourette’s syndrome (TS) is a complex neurological disorder. It is characterized by multiple tics – both motor and vocal. It is the most severe and least common tic disorder. This disorder is related to multiple neuroanatomical and neurophysiological deviations, primarily reduced sensorimotor rhythm (SMR) and excessive fronto-central Theta activity. Recent research has proposed neurofeedback for Tourette Syndrome and Tic Disorders as a promising treatment option, particularly in terms of helping patients control their tics and treat the cognitive dysfunctions commonly associated with TS.
Tic disorders can usually be classified as motor, vocal, or Tourette’s syndrome, which is a combination of both. Motor and vocal tics can be short-lived (transient) or chronic. Tourette’s is considered to be a chronic tic disorder.
Children with transient tic disorder will present with one or more tics for at least 1 month, but for less than 12 consecutive months. The onset of the tics must have been before the individual turned 18 years of age. Motor tics are more commonly seen in cases of transient tic disorder than vocal tics. Tics may vary in type and severity over time. According to the American Academy of Child and Adolescent Psychiatry, a transient tic disorder, or provisional tic disorder affects up to 10% of children during their early school years.
Tics that appear before the age of 18 and last for 1 year or more may be classified as a chronic tic disorder. These tics can be either motor or vocal, but not both. A chronic tic disorder is less common than transient tic disorder, with less than 1% of children affected.
If the child is younger at the onset of a chronic motor or vocal tic disorder, they have a greater chance of recovery, with tics usually disappearing within 6 years. People who continue to experience symptoms beyond age 18 are less likely to see their symptoms resolved.
Some research suggests that tics are more common among children with learning disabilities and are seen more in special education classrooms. Children within the autism spectrum are also more likely to have tics.
Tourette’s syndrome (TS) is the most severe and least common tic disorder. The Centers for Disease Control and Prevention (CDC) report that the exact number of people with TS is unknown. CDC research suggests that half of all children with the condition are not diagnosed. Currently, 0.3% of children aged 6 to 17 in the US have been diagnosed with TS. Symptoms of TS vary in their severity over time. For many people, symptoms improve with age. TS is often accompanied by other conditions, such as attention deficit hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD).
Tourette Syndrome is a neurodevelopmental disorder characterized by persistent, chronic, and involuntary tics. These tics manifest as either motor or phonic (vocalizations) and can range from simple tics such as blinking, sniffing, and head twitching to more complex such as repetitive swearing, spinning around, and jumping. The cause of Tourette’s is unknown but it is likely that both hereditary and nongenetic factors contribute to its development.
The onset of Tourette syndrome is usually in childhood between the ages of 2 and 21 years. The disorder affects more males than females with a ratio of approximately 3 males to every 1 female diagnosed. Tourette’s is a highly individualistic disorder with differing levels of severity, frequency, and impairment.
Whilst the exact cause of Tourette Syndrome is unknown, it is believed that the presence of tics is associated with abnormalities in the brain. In particular, it is suggested there is a distribution in the circuits which link the basal ganglia (the site which controls voluntary motor movements, eye movements, and emotion) to the frontal cortex.
Individuals with Tourette Syndrome display impaired performance in cognitive tasks in terms of memory, attention, reading, and writing. These impairments are often more severe in individuals diagnosed with comorbid ADHD who also display less cognitive flexibility. It is estimated that 70% of patients with Tourette Syndrome exhibit ADHD type behaviors and as such, Tourette Syndrome can be a debilitating diagnosis for many people.
If someone has tics, it doesn’t mean that this person has Tourette’s syndrome. Tics have to be present for at least one year to be classified as Tourette’s syndrome and at least one of tics has to be vocal.
Symptoms of Tic Disorder
The defining symptom of tic disorders is the presence of one or more tics. These tics can be classified as:
- Motor tics: These include tics, such as head and shoulder movements, jerking of the head, twisting the neck, rolling the eyes, blinking, jerking, banging, clicking fingers, or touching things or other people. Motor tics tend to appear before vocal tics, although this is not always the case.
- Vocal tics: These are sounds, such as coughing, blowing, throat clearing or grunting, or repeating words or phrases.
Tics can also be divided into the following categories:
- Simple tics: These are sudden and fleeting tics using few muscle groups. Examples include nose twitching, eye darting, or throat clearing.
- Complex tics: These involve coordinated movements using several muscle groups. Examples include hopping or stepping in a certain way, gesturing, or repeating words or phrases.
Tics are usually preceded by an uncomfortable urge, such as an itch or tingle. While it is possible to hold back from carrying out the tic, this requires a great deal of effort and often causes tension and stress. Relief from these sensations is experienced upon carrying out the tic.
The symptoms of tic disorders may:
• worsen with emotions, such as anxiety, excitement, anger, and fatigue,
• worsen during periods of illness,
• worsen with extreme temperatures,
• occur during sleep,
• vary over time,
• vary in type and severity,
• improve over time.
Causes and risk factors for Tourette's syndrome and Tic Disorders
The exact cause of tic disorders is unknown. Within Tourette’s research, recent studies have identified some specific gene mutations that may have a role. Brain chemistry also seems to be important, especially the brain chemicals glutamate, serotonin, and dopamine.
Tics that have a direct cause fit into a different category of diagnosis. These include tics due to:
• head injuries,
• other injuries.
In addition, tics can be associated with more serious medical disorders, such as Huntington’s disease or Creutzfeldt-Jakob disease.
Risk factors for tic disorders include:
• Genetics: Tics tend to run in families, so there may be a genetic basis to these disorders.
• Sex: Men are more likely to be affected by tic disorders than women.
Conditions associated with tic disorders
Conditions associated with tic disorders, especially in children with TS, include:
• autic spectrum disorder
• learning difficulties
• speech and language difficulties
• sleep difficulties
Other conditions associated with tic disorders are related to the effect of the tics on self-esteem and self-image. Some research has found that children with TS or any chronic tic disorder experience a lower quality of life and lower self-esteem than those without one of these conditions.
In addition, the Tourette Association of America says that people with TS often experience difficulties with social functioning due to their tics and associated conditions, such as ADHD or anxiety.
Brain changes in Tourette's Syndrome and Tic Disorders
The frequent comorbidity of TS and ADHD may reflect a common underlying neurobiological substrate, and studies confirm the hypothesized involvement of fronto-striatal circuits in both TS and ADHD. However, poor inhibitory control and volumetric reductions in fronto-striatal circuits appear to be core features of ADHD, whereas reduced volumes of the caudate nucleus, together with activation and hypertrophy of prefrontal regions that likely help to suppress tics, seem to be core features of TS. (Neuroimaging of tic disorders with co-existing attention-deficit/hyperactivity disorder – Kerstin J. Plessen, M.D., Jason M. Royal, D.M.A., and Bradley S. Peterson, M.D.)
Activity in a region of the brain called the supplementary motor area (SMA) has been associated with tics. The investigators put tic patients into the MRI scanner and had a real-time functional magnetic resonance imaging neurofeedback session. The patients could see the SMA light up and they could try to control that area by focusing their thoughts on it. The patients who received the real neurofeedback had a greater reduction of tics on the Yale Global Tic Severity Scale as compared with the sham control.
Researchers at Washington University School of Medicine in St. Louis have identified areas in the brains of children with Tourette’s syndrome that appear markedly different from the same areas in brains of children who don’t have the disorder.
In kids with Tourette’s, the researchers also found less white matter around the orbital prefrontal cortex, just above the eyes, and in the medial prefrontal cortex, also near the front, than in kids without the condition.
White matter acts like the brain’s wiring. It consists of axons that — unlike the axons in gray matter — are coated with myelin and transmit signals to the gray matter. Less white matter could mean less efficient transmission of sensations, whereas extra gray matter could mean nerve cells are sending extra signals.
In a scan of a child with Tourette’s, yellow indicates an area with less white matter than in the same brain region in kids who don’t have the disorder. The scans also revealed areas in the brains of kids with Tourette’s that have more gray matter (posterior thalamus, hypothalamus, and midbrain) than in children without the condition.
Deficits in executive functioning which contribute to ADHD symptoms also appear in TS, with the same losses of structural integrity in the cortico-striatal and cortico-thalamic pathways common to both disorders. Neurophysiological processes governing these deficits in executive functioning have proven modifiable by neurofeedback.
Clinical researchers Chuanjun Zhuo & Li Li (2014) found that neurofeedback training improved motor and vocal tic symptoms (e.g. a reduction in the frequency and intensity of tics) in adolescents with refractory Tourette syndrome.
Simone Messerotti Benvenuti et al. (2011) SMR up-training/Theta down-training schedule was utilized for sixteen sessions, followed by a further six purely using SMR up-training. SMR increase was better obtained when SMR up-training was administered alone, Whereas Theta decrease was observed after both types of trainings.
After 40 sessions of SMR training, 75% of patients demonstrated an increase in the production of SMR and a positive change in theta/beta ratio.
It was therefore hypothesized that this training of the sensorimotor cortex results in increased voluntary muscle control and elimination of tics.
Neurofeedback for Tourette syndrome and Tic Disorders
Neurofeedback training is a self-regulation strategy. The brain is trained at the point where the tics are to reduce or eliminate them. In a brain with TS there is over-arousal. There is a high degree of excitability of the motor system. The overarching need is for this brain to experience calming, both in general and specifically in regard to motor circuits. When such calming is achieved tics (motor and vocal) may be reduced.
With the right approach, Neurofeedback practitioners have seen significant improvement in symptoms in the vast majority of cases. Nonetheless every case is different and sometimes you may not experience the reduction of tics but overall you should feel more relaxed and you should notice a better quality of sleep. This is a condition that appears to benefit from long-term training.
Presently, medications used to treat tics can cause unforeseen side effects, whereas neurofeedback therapy can be tailored to more accurately target the area of the brain that needs changing.
Neurofeedback for Tourette Syndrome - Protocols
1. Sensor Placement:
Neurofeedback for Tourette syndrome typically involves the application of electrodes to specific sites on the scalp according to the 10-20 system, a standardized method for locating and measuring EEG electrode placements.
Common electrode sites include Cz (vertex), Fz (midline frontal), C3/C4 (left and right central), and Pz (midline parietal).
2. Frequency Bands:
Neurofeedback protocols often target specific frequency bands associated with neurological functioning. For TS, protocols may focus on training specific frequencies like the sensorimotor rhythm (SMR) and beta waves. SMR is associated with motor control and inhibition and is often implicated in TS symptomatology.
3. Operant Conditioning:
The neurofeedback for Tourette Syndrome involves operant conditioning, where individuals learn to regulate their brain activity in response to visual or auditory feedback. In the case of TS, patients might receive positive feedback when their brain activity corresponds to a desired state (e.g., reduced hyperactivity in certain brain regions).
Electrode Application Sites According to 10-20 System
1. Cz (Vertex): Often associated with overall brain regulation.
2. Fz (Midline Frontal): May target prefrontal areas associated with impulse control.
3. C3/C4 (Left and Right Central): Relevant for sensorimotor rhythm and motor control.
4. Pz (Midline Parietal): Associated with sensory processing and integration.
Effectiveness of Neurofeedback for Tourette Syndrome
Research on neurofeedback for Tourette syndrome is still in its early stages, and findings vary. Some studies suggest positive outcomes, such as reduced tic severity and improved impulse control, while others report mixed or inconclusive results.
Studies Supporting Effectiveness:
1. A study by Sokhadze et al. (2010) found that neurofeedback training led to a significant reduction in tic frequency and improved behavioral measures in TS patients.
2. Gevensleben et al. (2014) reported positive effects of neurofeedback on tic reduction and attentional control in children with TS.
Studies with Mixed Results:
1. Dehghani-Arani et al. (2013) found improvements in tic severity and cognitive performance but reported variability in individual responses.
2. Holtmann et al. (2011) observed improvement in tic severity but did not find significant effects on comorbid symptoms.
Challenges and Considerations:
• The heterogeneity of Tourette syndrome poses a challenge, as individuals may respond differently to neurofeedback.
• Lack of standardized protocols across studies makes it difficult to draw consistent conclusions.
• Larger, well-controlled studies with long-term follow-up are needed to establish the efficacy and generalizability of neurofeedback for TS.
In conclusion, while there is some promising evidence supporting the effectiveness of neurofeedback for Tourette syndrome, further research is necessary to establish standardized protocols, determine optimal electrode placements, and address the variability in treatment outcomes. Neurofeedback for Tourette syndrome holds potential as a complementary