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Parkinsonian Gait is the type of gait exhibited by patients suffering from Parkinson's disease. Typical features of the Parkinsonian gait are small shuffling steps and a general poverty and slowness of movement, called hypokinesia. Compared to healthy elderly subjects, patients with PD demonstrate reduced stride length and walking velocity during free ambulation. Double support duration and cadence rate are increased

Heel to Toe characteristics
Whereas in normal gait, the heel strikes the ground before the toes (also called heel-to-toe walking), in parkinsonian gait, motion is characterised by flat foor strike (where the entire foot is placed on the ground at the same time) or less often and in the more stages of the disease by toe-to-heel walking (where the toes touch the ground the before the heel.)In addition PD patients have a reduced foot lifting during the swing phase, which produces a smaller clearance between the toes and the ground.

Parkinson patients also have a reduced impact at heel strike. This mechanism is found to be related to the severity of the disease. Furthermore, Parkinson patients show a trend towards higher relative loads in the forefoot regions combined with a load shift towards medial foot areas. These mechanisms are highly stereotypical. .

Vertical ground reaction force
The vertical ground reaction force (GRF) component in normal gait has typically two peaks separated by a force minimum in the middle part of the GRF curve. The first peak occurs with heel strike while the second peak is caused by the push-off from the ground. Force reduction in the middle part of the force curve becomes more pronounced with higher walking speeds. This is a consequence of GRF reduction by knee flexion of the supporting leg and lift of the center of mass (CoM) by the swinging leg. It is found that the shape of the vertical GRF signal is abnormal in PD. Reduced forces are found for heel contact and the push-off phase. The shape of the vertical GRF signal, including two marked peaks are similar for PD patients with moderate gait disorder as compared to elderly controls. PD patients with the typical shuffling gait show only one narrow peak in vertical GRF signal.

Falls and Freezing of Gait
Falls and freezing of gait are two “episodic” phenomena that are common in Parkinson’s disease.Falls and FOG are generally thought to be closely intertwined, for various reasons. First, both symptoms seem most common in advanced PD but are deemed to be rare in earlier stages of the disease. Second, sudden FOG is likely to disturb balance and thereby represent a common cause of falls in PD. Third,recent observations have shed new light on the poorly understood pathophysiology underlying falls and FOG and suggested the possibility of shared and common pathologic mechanisms. Fourth, falls and FOG often respond poorly and sometimes paradoxically to treatment with dopaminergic medication, perhaps pointing to a common underlying pathophysiology. Fifth, the episodic and unpredictable nature of falls and FOG underscores the possible connections between these phenomena in PD.

Freezing of gait (FOG) can be very disabling,impairing mobility and restricting independence. Typically, FOG is a transient episode, lasting <1 min, in which gait is halted and the subject complains that his feet are glued to the ground. When the patient overcomes the block, walking can be performed relatively smoothly. The most common form of FOG to be start hesitation followed in frequency by turning hesitation FOG can also be experienced in narrow or tight quarters such as a doorway, whilst adjusting one’s steps when reaching a destination, and in stressful situations such as when the telephone or the doorbell rings or when the elevator door opens. As the disease progresses, FOG can appear spontaneously even in an open runway space
 * Freezing of Gait

Balance is typically preserved early in the course of idiopathic PD, and falls are rare during the first few years after disease onset.However, eventually most patients will sustain recurrent falls. Many falls result from sudden changes in posture, in particular turning movements of the trunk, or attempts to perform more than one activity simultaneously with walking or balancing.Falls are also common during transfers, such as rising from a chair or bed. Falls due to trips or slips are relatively rare. PD patients fall mostly forward (45% of all falls), and some 20% of falls were laterally directed
 * Falls

Postural Sway
Postural instability in upright stance is common in end-stage Parkinson's disease (PD) and compromises the ability to maintain balance during everyday tasks such as walking, turning and standing up from sitting. Due to an inability to adequately balance the body's centre of mass over the base of support, patients with advanced PD are predisposed to loss of equilibrium and falls.Although 40% of patients with end-stage disease have falls, many studies have shown only minor differences between patients with PD and control subjects in the execution of postural responses.Whereas postural sway is usually increased in patients with balance disorders arising from stroke, head injury and cerebellar ataxia it is often reduced in patients with PD. The problem in PD appears to be a lack of flexibility in shifting postural responses and adjusting reflex gain according to changing task demands rather than a disorder in the sequencing of postural responses.

Drugs
The most widely used form of treatment is L-dopa in various forms. L-dopa is transformed into dopamine in the dopaminergic neurons by L-aromatic amino acid decarboxylase (often known by its former name dopa-decarboxylase). However, only 1-5% of L-DOPA enters the dopaminergic neurons. The remaining L-DOPA is often metabolised to dopamine elsewhere, causing a wide variety of side effects. Due to feedback inhibition, L-dopa results in a reduction in the endogenous formation of L-dopa, and so eventually becomes counterproductive. The stride length and the kinematic parameters (swing velocity, peak velocity) related to the energy are Dopa-sensitive. Temporal parameters (stride and swing duration, stride duration variability), related to rhythm, are Dopa-resistant. Levodopa treatment decreases the frequency and the akinetic type of FOG, with a tendency for shorter FOG episodes. Parkinson’s disease have abnormal postural sway in stance and treatment with levodopa increases postural sway abnormalities
 * Effect on gait parameters:
 * Effect on falls and Freezing of Gait
 * Effects on Postural Sway

Auditory and Visual Cues
The visual cues are commonly transverse lines or rods on the floor, These types of visual cues have been associated with increases in stride length and velocity.
 * Visual Cues

The auditory cues are commonly rhythmic cues generated by a metronome or equivalent, sometimes embedded in music,set at or slightly above the subject’s usual cadence. In single session studies, rhythmic auditory cues have been associated with increases in velocity and cadence and sometimes stride length.Training with rhythmic auditory stimulation has also been associated with increases in velocity, cadence and stride length
 * Auditory Cues

Deep Brain Stimulation
Bilateral subthalamic nucleus stimulation has been the most common.