Functional changes of the cortical motor system in hereditary spastic paraparesis

• Published in: Acta neurologica Scandinavica Vol. 120; no. 3; pp. 182 - 190
• Main Authors: Koritnik, B., Azam, S., Knific, J., Zidar, J.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-09-2009; Blackwell
• Subjects: Adult; Biological and medical sciences; Brain Mapping; cerebellum; Cerebral Cortex - physiopathology; Diseases of the nervous system; Female; functional imaging; Functional Laterality; hereditary spastic paraparesis; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Medical sciences; Middle Aged; motor cortex; Movement; Neurology; Neuronal Plasticity; Paraparesis, Spastic - genetics; Paraparesis, Spastic - physiopathology; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); voluntary movements; Cerebellum; Nervous system diseases; Motor pathway; Motor system disorder; Central nervous system; Paraparesia; hereditary spastic paraparesis; Encephalon; Motor cortex; Paresis; Neurological disorder; voluntary movements; Functional imaging
• ISSN: 0001-6314; 1600-0404
• DOI: 10.1111/j.1600-0404.2008.01143.x

Background –  Hereditary spastic paraparesis (HSP) is a heterogeneous group of disorders characterized by progressive bilateral lower limb spasticity. Functional imaging studies in patients with corticospinal tract involvement have shown reorganization of motor circuitry. Our study investigates functional changes in sensorimotor brain areas in patients with HSP.
Methods –  Twelve subjects with HSP and 12 healthy subjects were studied. Functional magnetic resonance imaging (fMRI) was used to measure brain activation during right‐hand finger tapping. Image analysis was performed using general linear model and regions of interest (ROI)‐based approach. Weighted laterality indices (wLI) and anterior/posterior indicies (wAI and wPI) were calculated for predefined ROIs.
Results and discussion –  Comparing patients and controls at the same finger‐tapping rate (1.8 Hz), there was increased fMRI activation in patients’ bilateral posterior parietal cortex and left primary sensorimotor cortex. No differences were found when comparing patients and controls at 80% of their individual maximum tapping rates. wLI of the primary sensorimotor cortex was significantly lower in patients. Subjects with HSP also showed a relative increase in the activation of the posterior parietal and premotor areas compared with that of the primary sensorimotor cortex. Our findings demonstrate an altered pattern of cortical activation in subjects with HSP during motor task. The increased activation probably reflects reorganization of the cortical motor system.