D2.1 Requirements and Specification - CORBYS

D2.1 Requirements and Specification
extrapyramidal gait disorders with involuntary movements (e.g. tremor, ballistic or other not controllable
movements.
However, it is not wise to define groups of patients, neither by etiological diagnosis nor by gait patterns, since
gait patterns are highly individual. The reasons for this are:
� the aetiology of a disease (e.g. stroke, traumatic brain injury, etc) may lead to very different symptoms
(e.g. hemiparesis, spasticity, etc.)
� the symptoms can be more or less severe, leading to very different requirements.
� Additionally, different symptoms can appear simultaneously and influence each other, e.g. a certain
degree of spasticity in case of severe weakness is necessary to stand and walk.
� And on top, cognitive functions and capacities, pain, anxiety etc. are often also involved and may
change the gait pattern again.
4.1.2 Gait biomechanics in normal and pathological walking
4.1.2.1 Normal walking
Figure 1 displays positions of human trunk, pelvis and lower extremities in seven instances of gait cycle
(between two consecutive contacts of the same leg). In general human walking may be decomposed into
sagittal, frontal and transversal movement, with sagittal and frontal movement being the main contributor to
dynamic stability as well as to forward propulsion and forward progression. When observing human walking
we notice:
� alternating phases of flexion and extension in ankle, knee and hip joint in sagittal plane (red arrows)
� alternating phases of pelvic internal and external rotation (red box)
� alternating phases of hip abduction and adduction combined with ankle, knee and hip flexion/extension
during WEIGHT TRANSFER and FOOT CLEARANCE in frontal plane (red arrows) - this also
implies the necessity for pelvic sideways movement (red arrows)
� alternating phases of pelvic up and down movement/tilt in frontal plane (red box)
� ankle varus/valgus in frontal plane (blue arrows)
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