Is teeth chattering a symptom of extrapyramidal symptoms (EPS) or bruxism?

Teeth Chattering: Extrapyramidal Symptom or Bruxism?

Teeth chattering is primarily classified as a form of bruxism rather than an extrapyramidal symptom (EPS). While both conditions can affect orofacial movements, they have distinct clinical presentations and etiologies.

Distinguishing Between Bruxism and EPS

Bruxism

• Definition: Abnormal repetitive movement disorder characterized by jaw clenching and tooth gnashing or grinding 1
• Types:
  • Awake bruxism (AB): Conscious teeth clenching during wakefulness
  • Sleep bruxism (SB): Unconscious grinding or clenching during sleep
• Clinical presentation: Teeth chattering, grinding, clenching, gnashing
• Associated symptoms: Morning headaches, jaw pain/tightness 2

Extrapyramidal Symptoms

• Definition: Side effects from dopamine blockade or depletion in basal ganglia 3
• Types:
  • Dystonia: Sudden spastic contraction of distinct muscle groups (neck, eyes, torso)
  • Parkinsonism: Bradykinesia, tremors, rigidity
  • Akathisia: Severe restlessness, pacing, agitation
  • Tardive dyskinesia: Involuntary athetoid/choreic movements, primarily orofacial 4
• Clinical presentation: Typically involves sustained muscle contractions or repetitive movements, not specifically teeth chattering

Differential Diagnosis

When evaluating teeth chattering, consider:

1. Bruxism-related causes:

   • Stress/anxiety
   • Sleep disorders
   • Occlusal factors
   • Neurological conditions (Huntington's, Rett's syndrome, Down syndrome) 1

2. Medication-induced movement disorders:

   • Antipsychotic medications
   • Some antidepressants
   • Anticonvulsants
   • Antiemetics 3

3. Neurological disorders:

   • Primary dystonia
   • Secondary dystonia
   • Multiple sclerosis (can trigger bruxism) 2
   • Movement disorders with basal ganglia dysfunction 1

Assessment Approach

When evaluating teeth chattering:

1. Timing assessment:

   • When does it occur? (During sleep vs. wakefulness)
   • Duration and periodicity 4

2. Associated factors:

   • Medication history (particularly antipsychotics)
   • Clenching/bruxing habits
   • Other movement disorders
   • Psychological factors (stress, anxiety) 4

3. Physical examination:

   • Muscles of mastication (tenderness, hypertrophy)
   • Temporomandibular joint examination
   • Dental wear patterns (indicating bruxism)
   • Cranial nerve examination 4

Clinical Implications

The distinction between bruxism and EPS is important for treatment:

• If bruxism: Treatment may include occlusal splints, stress management, and in severe cases, botulinum toxin injections 2
• If EPS: Management typically involves adjusting antipsychotic medication, adding anticholinergic agents, or switching to atypical antipsychotics with lower EPS risk 4

Common Pitfalls

1. Misdiagnosis: Akathisia (an EPS) is often misinterpreted as psychotic agitation or anxiety 4
2. Overlooking comorbidities: Bruxism has been associated with ADHD and oppositional defiant disorder in children 5
3. Medication oversight: Not recognizing that non-antipsychotic medications can also cause EPS-like symptoms 3
4. Treatment delay: Failing to address teeth chattering can lead to dental damage, pain, and reduced quality of life

In conclusion, while teeth chattering can occasionally be part of complex movement disorders that include EPS, it is more accurately classified as a form of bruxism in most clinical contexts.