Electrophysiological characterisation in hereditary spastic paraplegia type 5

Area of Science:

• Neuroscience
• Genetics
• Clinical Electrophysiology

Background:

• Hereditary spastic paraparesis (HSP) is a group of inherited neurological disorders.
• SPG5 is a rare form of HSP with variable clinical presentations.
• Understanding the full extent of nervous system involvement in SPG5 is crucial for diagnosis and management.

Purpose of the Study:

• To comprehensively assess central (CNS) and peripheral (PNS) nervous system involvement in SPG5 HSP using multimodal electrophysiology.
• To investigate the diagnostic utility of electrophysiological tests in SPG5.

Main Methods:

• Four patients with molecularly confirmed SPG5 HSP underwent extensive electrophysiological testing.
• Tests included electromyography (EMG), nerve conduction studies (NCS), motor-evoked potentials (MEPs), somatosensory evoked potentials (SEPs), visual evoked potentials (VEPs), and brainstem auditory evoked potentials (BAEPs).
• One patient had serial evaluations over 19 years.

Main Results:

• EMG and NCS were normal, indicating peripheral nervous system (PNS) sparing.
• MEPs and SEPs showed abnormalities along the CNS pathways for both upper and lower limbs.
• VEPs and BAEPs revealed damage in the visual and auditory pathways, respectively.

Conclusions:

• SPG5 HSP demonstrates diffuse CNS involvement with preserved PNS function.
• Electrophysiological evaluation is valuable for diagnosing SPG5 and monitoring potential treatments.
• The SPG5 phenotype is broader than previously recognized, encompassing significant CNS pathology.