Emotional lability (pseudobulbar affect)

Upper motor neurone involvement is associated with pseudobulbar affect or emotional lability. This is a troubling symptom that occurs in as many as half of all people living with motor neurone disease (MND Australia 2011).

It may involve excessive laughing or crying, or involuntary emotional expression (Miller and others 2009b).

MND Australia 2011

Management

treatment with amitriptyline or drugs in the SSRI class may be helpful
dextropethorphan (cough syrup) and modafinil have also been found to reduce this symptom

Miller and others 2009b

What pharmacologic measures reduce pseudobulbar affect?

Pseudobulbar affect, excessive laughing or crying, or involuntary emotional expression disorder affects 20%–50% of patients with ALS, especially in pseudobulbar palsy. Although it is not a mood disorder, antidepressants are frequently employed.
A fixed-dose combination of dextromethorphan (DM)/quinidine (Q) (30 mg DM/30 mg Q BID) for treatment of pseudobulbar affect in ALS (Class I) reduced the frequency and severity of laughing and crying behaviors compared to either DM (p < 0.001) or Q alone (p < 0.001). Side effects were dizziness, nausea, and somnolence, which accounted for termination of treatment in 24% with DM/Q compared to 6% with DM and 5% with Q. DM/Q is not yet approved by the US Food and Drug Administration (FDA).
Conclusions
- The combination of DM/Q is probably effective for pseudobulbar affect in ALS (1 Class I study), although side effects may limit its usefulness.
Recommendation
- [FOR USA] If approved by the FDA, and if side effects are acceptable, DM/Q should be considered for symptoms of pseudobulbar affect in patients with ALS (Level B).