No abstract

The new and clinically relevant finding of this study is that imbalance and falls in PSP are closely associated with thalamic dysfunction. Deficits in thalamic postural control get most evident when balance is assessed during modified sensory input. The results are consistent with the hypothesis that reduced thalamic activation via the ascending brainstem projections may cause postural imbalance in PSP.

Gait impairment in PSP is especially associated with dysfunction of the indirect, modulatory prefrontal-subthalamic-pedunculopontine loop of locomotor control. The direct, stereotyped locomotor loop from the primary motor cortex to the spinal cord with rhythmic cerebellar drive shows increased activity in PSP. The latter can be interpreted as an attempt of compensation, but may also contribute to a stereotyped gait pattern in PSP.

No abstract