Proportional recovery from impairment after stroke: why 70%? Event as iCalendar


08 August 2017

4 - 5pm

Venue: Ground floor seminar room (G10)

Location: 70 Symonds St, Auckland Central


 An ABI seminar by Dr Cathy Stinear, Associate Professor, Department of Medicine, University of Auckland

Stroke is a leading cause of adult disability, affecting 6,000 New Zealanders and 15 million people worldwide each year. Motor impairment is common after stroke, affecting around 80% of patients. Recovery of movement is crucial to regaining independence. Spontaneous biological recovery takes place in the initial days and weeks after stroke, and remarkably this results in most patients recovering about 70% of the available improvement in motor impairment in both the upper and lower limb. This is known as proportional recovery, or the 70% rule, which holds true for the majority of patients across all ages and genders, and in countries with different rehabilitation services. The mechanisms underlying proportional recovery are unclear. We discovered that proportional recovery from upper limb impairment is unaffected by therapy dose, and depends on having a functional corticomotor pathway that can still convey motor commands from the brain to the spinal cord. This is evident by the presence of motor evoked potentials in response to transcranial magnetic stimulation (MEP+). Patients who are MEP+ follow the 70% rule, while MEP- patients do not. We also discovered that recovery from lower limb impairment is proportional (about 70%) and unaffected by therapy dose. Why doesn’t therapy interact with the neurobiological mechanisms of recovery from impairment? And why does impairment recover by around 70%, and not some other number? This seminar will discuss what we know so far, and invite your discussion of possible mechanisms and ways to measure them.