Echogenicity of basal ganglia structures in different phenotypes of Huntington's disease

Introduction: In Huntington's disease (HD), a neurodegenerative inherited disease, chorea as the typical kind of movement disorder is described. Beside chorea, however, all other kinds of movement disorders, such as bradykinesia, dystonia, tremor or myoclonus can occur. Aim of the current study was to investigate alterations in the echogenicity of basal ganglia structures by transcranial sonography (TCS) in different Huntington's disease phenotypes.

Method: 45 patients with manifest and genetically confirmed HD were recruited. All participants underwent a thorough neurological examination. For classification into predominantly choreatic, mixed or bradykinetic-rigid motor phenotypes we used a method described earlier. Furthermore, we analyzed juvenile HD as additional subgroup. Transcranial sonography was performed by an investigator blinded to the clinical status.

Results: There were no significant changes in basal ganglia echogenicities between predominantly choreatic, mixed or bradykinetic-rigid motor phenotypes. Comparing echogenicity of the substantia nigra (SN) structures between the juvenile and adult HD, a significantly higher occurrence of pathological hyperechogenicities in the SN (p = 0.003). Also the sum area of SN-hyperechogenicity (cm²) in the juvenile HD subgroup was higher (p = 0.032).

Discussion: Patients with the rather akinetic-rigid juvenile HD (Westphal variant) exhibited consistently hyperechgenicities of Substantia nigra. Thus, a distinct different underlying pathophysiology of the disease in juvenile compared to adult HD is discussed. Beyond, no significant differences between the different phenotypes were detected in the adult form of the disease.