The relationship between corticospinal tract and the affected lower limb function and walking ability in subacute stroke patients: a preliminary study.

One hospital, one time point, 40 people measured once. Nobody was followed up, so the study cannot say whether any of this predicts who recovers or how. Only 13 people had a bleed, so the comparison between stroke types rests on very few people. Everyone's tract was relatively well preserved (mean rFA above 0.9), so people with severe tract damage are barely represented. The measure was taken from the cerebral peduncles, which carry fibres other than the corticospinal tract, so it is not a pure measure of that tract. The scanner was 1.5-T with 12 diffusion directions. The authors note that a 3.0-T, 45-direction study found no link with lower limb scores, and say their own imaging conditions give a less valid measure. Hip extensor strength was tested lying on the back rather than face down, a position the authors say can let a whole-leg extension pattern generate the force, which may be why it behaved differently from the other muscles.

The authors report that the work received no funding and declare no conflicts of interest.

Do not read this as a scan that predicts how well someone will walk. It is one measurement taken once in 40 people, most of whom had relatively preserved tracts, and it cannot show what happens later or whether the tract itself drives recovery. Nor should the hip extensor result be read as evidence that hip extensors are spared by tract damage. The authors say their lying-down testing position, not the tract, is the likely reason no link appeared.