Preparation lecture 7
Cohen (2013). Clinical assessment of Tourette syndrome and tic disorders.
Tourette syndrome (TS) has many characteristics including involuntary movements and sound,
markedly enhanced startle reactions, a tendency to repeat both vocalizations (echolalia) and
movements (echopraxia) and uncontrollable verbal obscenities (coprolalia). Co-occurring diseases are
ADHD and OCD.
Definition of tics
Tics appear as sudden, rapid, purposeless motor movements or sounds that involve discrete muscle
groups. Tics can be suppressed for a short duration, but this often causes discomfort. It can have
physical and neuropsychiatric consequences and diminish the patient’s quality of life. Often, the tics
themselves have less adverse effects than the co-occurring disorders.
Tourette syndrome and other tic disorders
An international prevalence of 0.6–1% has been reported for mainstream schoolchildren, with the
disorder being 3–4 times more common in males than in females. TS prevalence may differ in
prevalence worldwide due to either genetic or environmental differences. TS is defined by the pediatric
onset of both motor and vocal tics, lasting for at least one year. Tics exhibit several characteristics that
distinguish them from other common childhood movement disorder such as stereotypies, chorea’s and
dystonia’s. The distinguishing characteristics of tics include:
1. They wax-and-wane in severity.
2. The character of the movements changes over time.
3. They are temporality suppressible.
4. They are typically associated with sensory phenomena.
Natural history
Tics usually begin around 6–8 years of age, and 90–95% of TS cases have an onset of tics between the
ages of 4 and 13.
- Simple motor tics involving the eyes or face are usually the first to appear in children with TS.
Motor tics will typically progress in a rostral-caudal fashion and over time they tend to become
more complex, involving contractions of groups of muscles in a stereotyped, repetitive way.
1
, - Phonic tics usually appear after the onset of motor tics and can also progress from simple
vocalizations to more complex ones. Simple phonic tics are brief, meaningless vocalizations that
often consist of a single sound, such as grunting, squeaking, or sniffing, while complex phonic tics
can include uttering different words or phrases. Complex phonic tics are echolalia, palilalia
(repeating oneself), and coprolalia (saying obscene words or phrases).
Course -> the vast majority of children with tics improve. The severity of tics usually peaks at about
10–12 years of age, and in one half to two thirds of cases, symptoms will drastically reduce during
adolescence. In the rare cases in which tic severity persists into adulthood, tic symptoms are most
severe, characterized by self-injurious motor tics or coprolalic utterances.
Sensory phenomena surrounding tics
Sensory phenomena -> all-encompassing term to describe such subjective experiences as premonitory
urges, “just-right” perceptions, or somatic hypersensitivity.
Premonitory urges
These are uncomfortable sensory phenomena that typically precede and are subjectively experienced
as being the initiators of tics. It can be experienced by individuals with tics and are likened to the need
to sneeze or itch or an inner feeling of restlessness, pressure or mounting tension. The anatomical
regions with the greatest density of urges were the palms, shoulders, midline abdomen, and throat.
Thus, premonitory urges are focal in character and limited to specific anatomical locations. Typically,
the discomfort associated with the premonitory urge builds up until the tic is performed.
Awareness -> patients have reported an awareness of the premonitory urge helps them suppress
imminent tics because they are fore-warned of their arrival and can take measures to suppress them.
Awareness typically increases as children with TS become older. The delayed onset of awareness of
urges most likely represents the normal development self-awareness and the fact that younger children
are less able to recognize and describe bodily urges.
Somatic hypersensitivity
Sensorimotor gating -> the neurological processes of filtering out redundant or unnecessary sensory
stimuli. Prepulse inhibition (PPI) of startle to a high-intensity stimulus is an experimentally
measurable indication of sensorimotor gating. This is defined as the inhibitory effect of a low-intensity
stimulus or “prepulse”, on the startle response to the subsequent same, but high-intensity stimulus.
The prepulse is believed to activate brain mechanisms which suppress or “gate” the processing of that
stimulus for a brief window of time.
Hypersensitivity -> by many individuals described as being an important phenomenon intertwined
with other aspects of the disorder. In a study, examples of bothersome stimuli include: rough fabrics,
the constant pressure exerted by a shirt collar or a waistband, the pressure of a chair or another person’s
arm. Patients also described a preference for strong tactile stimuli such as having their skin scratched
or receiving a massage. The investigators did not observe in TS patients any greater ability to detect
different intensities of olfactory and tactile stimuli as compared to healthy volunteers. This led them to
suggest that the perceived sensitivities were the result of altered or impaired central processing.
2
Cohen (2013). Clinical assessment of Tourette syndrome and tic disorders.
Tourette syndrome (TS) has many characteristics including involuntary movements and sound,
markedly enhanced startle reactions, a tendency to repeat both vocalizations (echolalia) and
movements (echopraxia) and uncontrollable verbal obscenities (coprolalia). Co-occurring diseases are
ADHD and OCD.
Definition of tics
Tics appear as sudden, rapid, purposeless motor movements or sounds that involve discrete muscle
groups. Tics can be suppressed for a short duration, but this often causes discomfort. It can have
physical and neuropsychiatric consequences and diminish the patient’s quality of life. Often, the tics
themselves have less adverse effects than the co-occurring disorders.
Tourette syndrome and other tic disorders
An international prevalence of 0.6–1% has been reported for mainstream schoolchildren, with the
disorder being 3–4 times more common in males than in females. TS prevalence may differ in
prevalence worldwide due to either genetic or environmental differences. TS is defined by the pediatric
onset of both motor and vocal tics, lasting for at least one year. Tics exhibit several characteristics that
distinguish them from other common childhood movement disorder such as stereotypies, chorea’s and
dystonia’s. The distinguishing characteristics of tics include:
1. They wax-and-wane in severity.
2. The character of the movements changes over time.
3. They are temporality suppressible.
4. They are typically associated with sensory phenomena.
Natural history
Tics usually begin around 6–8 years of age, and 90–95% of TS cases have an onset of tics between the
ages of 4 and 13.
- Simple motor tics involving the eyes or face are usually the first to appear in children with TS.
Motor tics will typically progress in a rostral-caudal fashion and over time they tend to become
more complex, involving contractions of groups of muscles in a stereotyped, repetitive way.
1
, - Phonic tics usually appear after the onset of motor tics and can also progress from simple
vocalizations to more complex ones. Simple phonic tics are brief, meaningless vocalizations that
often consist of a single sound, such as grunting, squeaking, or sniffing, while complex phonic tics
can include uttering different words or phrases. Complex phonic tics are echolalia, palilalia
(repeating oneself), and coprolalia (saying obscene words or phrases).
Course -> the vast majority of children with tics improve. The severity of tics usually peaks at about
10–12 years of age, and in one half to two thirds of cases, symptoms will drastically reduce during
adolescence. In the rare cases in which tic severity persists into adulthood, tic symptoms are most
severe, characterized by self-injurious motor tics or coprolalic utterances.
Sensory phenomena surrounding tics
Sensory phenomena -> all-encompassing term to describe such subjective experiences as premonitory
urges, “just-right” perceptions, or somatic hypersensitivity.
Premonitory urges
These are uncomfortable sensory phenomena that typically precede and are subjectively experienced
as being the initiators of tics. It can be experienced by individuals with tics and are likened to the need
to sneeze or itch or an inner feeling of restlessness, pressure or mounting tension. The anatomical
regions with the greatest density of urges were the palms, shoulders, midline abdomen, and throat.
Thus, premonitory urges are focal in character and limited to specific anatomical locations. Typically,
the discomfort associated with the premonitory urge builds up until the tic is performed.
Awareness -> patients have reported an awareness of the premonitory urge helps them suppress
imminent tics because they are fore-warned of their arrival and can take measures to suppress them.
Awareness typically increases as children with TS become older. The delayed onset of awareness of
urges most likely represents the normal development self-awareness and the fact that younger children
are less able to recognize and describe bodily urges.
Somatic hypersensitivity
Sensorimotor gating -> the neurological processes of filtering out redundant or unnecessary sensory
stimuli. Prepulse inhibition (PPI) of startle to a high-intensity stimulus is an experimentally
measurable indication of sensorimotor gating. This is defined as the inhibitory effect of a low-intensity
stimulus or “prepulse”, on the startle response to the subsequent same, but high-intensity stimulus.
The prepulse is believed to activate brain mechanisms which suppress or “gate” the processing of that
stimulus for a brief window of time.
Hypersensitivity -> by many individuals described as being an important phenomenon intertwined
with other aspects of the disorder. In a study, examples of bothersome stimuli include: rough fabrics,
the constant pressure exerted by a shirt collar or a waistband, the pressure of a chair or another person’s
arm. Patients also described a preference for strong tactile stimuli such as having their skin scratched
or receiving a massage. The investigators did not observe in TS patients any greater ability to detect
different intensities of olfactory and tactile stimuli as compared to healthy volunteers. This led them to
suggest that the perceived sensitivities were the result of altered or impaired central processing.
2
