Found in both pure and complicated HSP
This Italian study of 47 HSPers, 21 with pure HSP and 26 with complicated HSP, has found poorer cognitive performance in both groups associated with brain white-matter damage, compared with 19 non-HSP control subjects.
The pattern of damage was different and more widespread with complicated HSP, along with larger memory and ‘executive function’* deficits. However these cognitive deficits were also present in the pure HSP group to a measurable extent.
(* ‘executive function’ is an umbrella term for cognitive processes such as planning, working memory, attention, problem-solving, verbal reasoning, inhibition, mental flexibility, multi-tasking, initiation and monitoring of actions.)
Objective: To investigate brain white matter (WM) damage in patients with pure (p) and complicated (c) hereditary spastic paraparesis (HSP).
Background Thin corpus callosum (CC) with or without periventricular WM abnormalities and variable patterns of WM atrophy have been described in HSP patients. However, the different topography of brain WM damage in pHSP and cHSP has not been investigated yet.
Design/Methods: Forty-seven HSP patients (21 pHSP, 26 cHSP) underwent clinical and neuropsychological assessment, genetic screening, and structural and diffusion tensor (DT) MRI. Nineteen healthy controls (HC) were also studied. Tract-based spatial statistics and voxel-based morphometry were used.
Results: In the pHSP group, there were 11 patients carrying a SPG4 mutation and one patient with a SPG3A mutation. In the cHSP group, SPG5 (one case), SPG7 (one case), SPG10 (one case), SPG11 (three cases), and SPG15 (two cases) mutations were found. Although cHSP patients performed lower than HC and pHSP patients in most of the investigated cognitive domains, cognitive deficits in memory and executive functions were also present in pHSP patients. A distributed pattern of microstructural WM damage involving most of the CC, corticospinal tracts, and main corticocortical associative tracts, bilaterally, was found in both pHSP and cHSP patients compared to controls. In pHSP patients, WM damage involved mainly the posterior brain regions, while in cHSP it was equally distributed in the anterior frontal and posterior parietal WM. Compared to HC, pHSP and cHSP patients showed WM volume loss in the mid-body and splenium of the CC, and brainstem, bilaterally. cHSP patients also showed atrophy of WM adjacent to the left primary motor cortex.
Conclusions: DT MRI showed that both pHSP and cHSP are associated with a distributed WM damage to the corticospinal, inter-hemispheric, and association tracts, suggesting that HSP is a multisystem disorder, with involvement outside the motor system.
SOURCE: Neurology April 24, 2012; 78(Meeting Abstracts 1): P03.164 doi: 10.1212/WNL.78.1
White Matter Damage in Pure and Complicated Hereditary Spastic Paraparesis (P03.164)
Antonio Scarale1, Marina Scarlato2, Federica Agosta3, Elisa Canu4, Maria Bassi5, Sara Benedetti6, Elisabetta Pagani7, Maurizio Ferrari8, Giancarlo Comi9, Andrea Falini10, Maria Sessa11 and Massimo Filippi12
1 San Raffaele Scientific Institute, Vita-Salute San Raffaele University Milan Italy 2 San Raffaele Scientific Institute, Vita-Salute San Raffaele University Milan Italy 3 San Raffaele Scientific Institute, Vita-Salute San Raffaele University Milan Italy 4 San Raffaele Scientific Institute, Vita-Salute San Raffaele University Milano Italy 5 E. Medea Scientific Institute Bosisio Parini Italy 6 San Raffaele Scientific Insitute Milan Italy 7 San Raffaele Scientific Institute, Vita-Salute San Raffaele University Milan Italy 8 San Raffaele Scientific Institute, Vita-Salute San Raffaele University Milan Italy 9 Milan Italy 10 San Raffaele Scientific Institute, Vita-Salute San Raffaele University Milan Italy 11 San Raffaele Scientific Institute, Vita-Salute San Raffaele University Milan Italy 12 San Raffaele Scientific Institute, Vita-Salute San Raffaele University Milan Italy