Extrapyramidal signs in normal pressure hydrocephalus: an objective assessment

Area of Science:

• Neurology
• Movement Disorders
• Neuroscience

Background:

• Normal Pressure Hydrocephalus (NPH) presents with classic symptoms like gait disturbance, incontinence, and dementia.
• However, motor dysfunction, particularly upper limb extrapyramidal signs, is also characteristic of NPH.
• These subtle movement disorders are often underappreciated and warrant further investigation for improved diagnosis and treatment.

Purpose of the Study:

• To objectively characterize upper limb extrapyramidal signs in NPH patients.
• To compare motor function in NPH subjects with healthy controls using sensitive methods.
• To evaluate the effects of cerebrospinal fluid (CSF) diversion on these motor signs.

Main Methods:

• Twenty-two NPH patients and 17 controls underwent an upper limb motor task battery.
• Objective measures of akinesia/bradykinesia, tone, and tremor were recorded.
• NPH subjects were tested before and after CSF drainage, and some after shunt placement.

Main Results:

• NPH subjects exhibited akinesia/bradykinesia and increased resting tone compared to controls.
• NPH patients struggled more with self-initiated versus stimulus-initiated tasks.
• CSF drainage led to reduced movement times and improved self-initiated task performance in some NPH subjects.

Conclusions:

• NPH patients display extrapyramidal motor signs beyond gait deficits, including bradykinesia, akinesia, and rigidity.
• These motor signs are exacerbated when external movement cues are absent.
• Temporary or permanent CSF diversion can objectively improve some, but not all, of these NPH-related motor features.