Hand muscles corticomotor excitability in hereditary spastic paraparesis type 4

Neurol Sci. 2014 Aug;35(8):1287-91. doi: 10.1007/s10072-014-1707-7. Epub 2014 Mar 20.


Transcranial magnetic stimulation (TMS) studies on the pathways to the upper limbs have revealed inconsistent results in patients harboring mutations in SPAST/SPG4 gene, responsible for the commonest form of hereditary spastic paraplegia (HSP). This paper is addressed to study the corticomotor excitability of the pathways to the upper limbs in SPG4 subjects. We assessed the corticomotor excitability of hand muscles in 12 subjects belonging to 7 unrelated SPG4 families and in 12 control subjects by stimulus-response curve [input-output (I-O) curve]. All the parameters of the recruitment curve (threshold, V50, slope and plateau) did not differ significantly from those of the controls. Presence of upper limb hyper-reflexia did not influence the results of I-O curve. Considering the multiplicity of possible genes/loci accounting for pure HSPs, performing TMS analyses could be helpful in differential diagnosis of pure HSPs in the absence of other clinical or neuroimaging tools.

MeSH terms

  • Adenosine Triphosphatases / genetics
  • Aged
  • Case-Control Studies
  • Evoked Potentials, Motor*
  • Female
  • Genes, Dominant
  • Hand / innervation*
  • Humans
  • Male
  • Middle Aged
  • Motor Cortex / physiopathology*
  • Muscle, Skeletal / innervation*
  • Neural Conduction
  • Neuroimaging
  • Prospective Studies
  • Reflex, Abnormal
  • Spastic Paraplegia, Hereditary / diagnosis
  • Spastic Paraplegia, Hereditary / genetics
  • Spastic Paraplegia, Hereditary / physiopathology*
  • Spastin
  • Transcranial Magnetic Stimulation*


  • Adenosine Triphosphatases
  • Spastin
  • SPAST protein, human