A study explored the causes of ataxia in the brains of stroke patients. Many of the strokes were found in areas outside the cerebellum.
A recent investigation led by the University of Turku and Turku University Hospital in Finland aimed to understand the roots of ataxia in stroke patients. Interestingly, a considerable portion of the stroke lesions was identified outside the cerebellum.
New research from a group in Finland revealed that, contrary to what is often taught in medical education, over half of the cerebrovascular issues leading to ataxia were situated completely outside the cerebellum and its connecting areas. These lesions were found in a brain network linked to the cerebellum.
Ataxia is a neurological disorder marked by challenges in coordinating voluntary movements. It can manifest in various neurological conditions, including stroke, multiple sclerosis, and neurodegenerative disorders, as well as from prolonged heavy alcohol consumption. Presently, treatment options for ataxia remain limited.
“Traditionally, ataxia is thought to stem from harm to the cerebellum or to its direct connections in the central nervous system. Nonetheless, ataxia has been seen in patients without damage to these areas, leaving some aspects of its biological mechanisms unclear,” explains Juho Joutsa, a Neurology Professor and lead investigator of the study at the University of Turku, Finland.
The research involved 197 individuals who had recently experienced a stroke and were receiving care in the stroke unit at Turku University Hospital. The study found that limb ataxia occurred in 18 percent of these patients (n=35/197). Surprisingly, only 46 percent of the lesions in these patients affected the cerebellum or its connecting structures.
An innovative imaging technique sheds light on neurological symptoms linked to brain networks
Doctoral researchers Oliver Liesmäki and Jaakko Kungshamn, along with their team at the University of Turku, unraveled this enigma by employing a relatively novel brain imaging technique from Harvard University. This method enables the exploration of brain connections disrupted by lesions.
The findings indicated that the lesions responsible for ataxia were actually part of a brain network that goes beyond the cerebellum and its immediate connections. This network includes the dentate nucleus, globose nucleus, and emboliform nucleus in both hemispheres of the cerebellum.
Subsequently, the researchers evaluated the predictive capabilities of this identified brain network using a separate dataset of 96 stroke patients and found that strokes within this network did indeed forecast the onset of limb ataxia in these individuals.
This research alters our understanding of the neurological foundations of ataxia and could influence medical education significantly.
“Ataxia can also arise as a possible consequence of functional neurosurgery. Recognizing the ataxia network may enhance the safety of these procedures in the future,” states Liesmäki.
The findings of this research were published on August 29, 2024, in Neurology.
