21st November 2023

Tics & Tremors

Tics

Tics are repetitive, rhythmic movements which are spontaneous and seen more commonly in boys (Centers for Disease Control and Prevention, 2022). They can occur in motor and / or vocal modalities but can only be partially resisted by the individual (and so can be temporarily suppressed), though this is often difficult.

Tic disorders

As per the ICD-11:

• Tourette’s syndrome  – Involves tics in BOTH the motor and verbal modalities, with multiple motor symptoms and at least one verbal symptom for diagnosis (with symptoms occurring for >12 months).
• Chronic tic disorder  – These occur in EITHER the motor or verbal modalities, with symptoms lasting >12 months.
• Transient tic disorder  – Symptoms lasting <12 months.

It is worth noting that tics can also be seen in infections (such as CJD) and triggered by medications (such as cocaine and other stimulants).

Tremors

These are rhythmic, involuntary movements of at least one body part. Tremors are the most common movement disorder that you’ll encounter in psychiatry and most commonly affect peripheral body parts such as the hands.

Extrapyramidal tremors

These are resting tremors, which are around 4Hz (Sanders and Gillig, 2012). These are seen in Parkinson’s disease, Parkinson’s plus, Parkinsonism and Lewy body dementia. The movement is often witnessed in the hands (pill rolling tremor) and limbs.

Cerebellar tremor

This is also known as an intention tremor and happens in the 4-6 Hz frequency. Evidence suggests that lesions in the dentate nucleus and superior cerebellar peduncle often lead to this kind of tremor (Thach et al., 1992).

Causes include alcoholism, multiple sclerosis, stroke and Friedreich’s ataxia.

Essential tremors

It is also known as benign essential tremor, which is seen on activity and around 4-12 Hz. The patient will often see symptoms symmetrically in the hands, head or even the voice (Louis, 2001). There is often a strong family history (Bain et al., 1994), and the patient may note that the tremor improves with alcohol. If the symptoms interfere with quality of life, then a beta blocker such as propranolol can be utilised (Pal, 2011).

Physiological tremor

A physiological tremor is a normal phenomenon. Due to it occurring in the 8-12 Hz frequency (Marshall, 1961), it cannot always be seen by the eye. It does, however, become noticeable in activity for some individuals under certain circumstances, including:

• Anxiety states.
• Medications  – Salbutamol, lithium.
• Drugs  – Caffeine, alcohol and opioid withdrawal.
• Medical conditions  – Hypoglycaemia, hyperthyroidism, pheochromocytoma.

Physiological treatments, on the whole, do not need treatment. Propranolol, however, has been used to good effect for individuals who want to suppress a tremor due to anxiety in triggering situations (such as when making a presentation).

Functional tremors

These are also known as psychogenic tremors (Deuschl et al., 2004) and often have a sudden onset, usually associated with a stressful life event. The tremor is seen at rest and on activity and spontaneously remits.