Transcranial magnetic stimulation (TMS) to predict balance and gait patterns following supratentorial stroke.

Standing and walking require highly integrated sensorimotor and higher
perceptual functions of the nervous system. A supratentorial stroke may impair
these functions, causing more or less severe postural imbalance and walking
disability. Recent longitudinal research concerning ambulation after stroke
demonstrates that the early-developed hemiparetic movement patterns do not
significantly change over time. These results suggest that it should be
possible to make early predictions of hemiparetic balance and gait patterns
based on more detailed measures of stroke-related primary impairments of distal
leg muscles.

Early individual prediction of balance and gait patterns is of great importance
for the optimalisation of rehabilitation strategies. For example, in the case
of expected poor recovery, measures to support ankle-foot functions such as
individually tailored orthoses or various ways of (non)invasive neuromodulation
are warrented to promote independence and to prevent secondary consequences
(muscle stiffness and contractures).

Because many problems of standing and walking after stroke originate from
weakness and muscular imbalance at the ankle foot level, this research project
mainly focuses at understanding and predicting the functions of the lower leg
muscles. Recent technical advances have made it possible to better discriminate
between essential inputs (corticospinal, reflexes) that drive the spinal
motoneurons essential to human standing and walking.

The basic question of this project is to what extent the (long term) functional
behavior of critical paretic lower leg muscles during standing and walking can
be understood and predicted by (early) assessment of the integrity of the
corticospinal connections to these muscles in patients with supratentorial
stroke.

Study I. Transcranial magnetic stimulation of lower leg muscles.
The first step in the proposed research project is to optimize and standardize
the method of TMS of the lower leg muscles by using a double-cone coil. This
part of the study will be conducted in a sample of 10 patients with chronic
supratentorial stroke involving the leg and 10 healthy age-referenced (elderly)
subjects. Additionally, five of the chronic stroke patients will undergo the
gait and balance protocol as delineated below, in order to test the protocol
for study II.

Study II. Transcranial magnetic stimulation in predicting hemiparetic balance
and gait patterns in acute stroke.
A cohort study will be conducted of 50 acute patients with a CT or MRI proven
first-ever supratentorial stroke. TMS at week 1-2 and at week 6. At week 6,
12 and 24, clinimetry, gait analysis and posturography.

Study III. Relationship corticospinal dysfunction and spastic gait in patients
with hereditary spastic paraparesis (HSP). Cross-sectional study in 10 HSP
patients, in whom TMS will be used to explain the spastic gait.

The main burden in this study arises from the TMS in the second week post
stroke. However, TMS is a noninvasive procedure with no risks, if patients are
properly included (see exclusion). TMS is applied in some acute stroke
patients in regular practice to gain prognostic information.

The gait analysis and the posturography is relatively time-consuming for the
patients, but not incrimating. These investigations are often experienced as
extended therapy sessions.