Question

Which one of the following is NOT true regarding Pseudobulbar palsy?

• A. Emotional incontinence
• B. Exaggerated jaw jerk
• C. Dysarthria
• D. Flaccid tongue

Hint:

Pseudobulbar palsy is an upper motor neuron disorder, so its tongue should be spastic, not flaccid.

Answer 1

The Correct Option is D

This question asks which listed feature does not actually belong to pseudobulbar palsy, an upper motor neuron disorder of the lower cranial nerves.

1. Emotional incontinence: This uncontrollable crying or laughing is a true, well recognized feature caused by loss of cortical control over emotional expression.
2. Exaggerated jaw jerk: This brisk reflex is a true upper motor neuron sign, since bilateral corticobulbar damage releases the reflex from cortical inhibition.
3. Dysarthria: This slurred speech is a true feature, caused by spastic weakness of the tongue, lips, and palate.
4. Flaccid tongue: This is actually a lower motor neuron sign belonging to true bulbar palsy. Since pseudobulbar palsy spares the lower motor neuron and only affects its upper motor neuron input, the tongue should be spastic, not flaccid, making this statement false.

Since pseudobulbar palsy is defined by upper motor neuron damage, a flaccid tongue does not fit and is the feature that is NOT true.

Note: the source paper's printed answer key marks option (b), exaggerated jaw jerk, as the exception, but jaw jerk exaggeration is a well established true upper motor neuron sign of pseudobulbar palsy, while tongue flaccidity is the lower motor neuron finding that does not belong. This solution follows the medically correct answer.

Let's summarize:

• Pseudobulbar palsy is caused by bilateral upper motor neuron damage, so its signs are all spastic/upper motor neuron in nature.
• A flaccid tongue is a lower motor neuron finding and does not belong to this picture.

So the feature that is NOT true of pseudobulbar palsy is a flaccid tongue.