PARKINSON’S DISEASE (Neurological Disorders in Elderly)
Definition
Parkinson’s
disease (PD) is a progressive neurodegenerative disease that is characterized
by
rigidity,
bradykinesia, resting tremor, mask like face and postural abnormalities. The
disease
was first described by Parkinson in 1807.
Prevalence
The
prevalence is approximately 1 percent in the general population, with the rate
rising from
0.6
percent for ages 60-64 to 3.5 percent for ages 85-89.12
Risk
Factors
PD
results from a reduction in the neurotransmitter dopamine stores of the
substantia nigra
with
a consequent loss of pigmentation in this structure. Though the exact cause is
unknown,
many
risk factors have been identified:
• Toxic
exposure: Several studies have identified a link between PD and the
exposure to pesticides,
insecticides,
herbicides and well water.13,14
• Genetics:
Individuals with family history, particularly first-degree relatives of
patients with
PD
are at approximately twice the risk for the disease.
• Aging:
Dopamine shows an increase in concentration very early in life, followed by a
rapid
decrease
from 5 to 20 years of age and a slow continuous loss from age 20 to 80 years.15
• Infections:
A high rate of postencephalitic parkinsonism suggests the important role of
infection
in
the incidence of PD.
• Medications:
Medications such as antipsychotic agents, Lithium, metroclopramide are known
to
be associated with parkinsonism.
Clinical
Features
The
triad of resting tremor, bradykinesia and rigidity is the key feature of PD.
• Tremor:
Though resting tremor is often considered the hallmark of PD, about 20 percent
of
parkinsonian
patients will lack tremor. The features of tremor with special reference to PD
are
described as below:
–
Present at rest
– Has a regular rhythm of about 4 to 7 beats/sec
–
Usually disappears with movement
–
Rarely interferes with ADL
–
No tremor during sleep
–
Some patients may have a postural tremor
–
“Pill-rolling”: The patient appears to be rolling a pill in his fingers as the
wrist cycles
between
pronation and supination
• Bradykinesia:
Bradykinesia is a term used to describe the slowness in the execution of
movement,
whereas akinesia refers to the paucity of movement and ‘freezing’or an
inability
to
move. In part, disorders of posture and locomotion found in the patients of PD
are
attributed
to bradykinesia. There is reduced magnitude of agonist muscle activity
associated
with
an excessive co-contraction of the antagonist during movement. The features of
bradykinesia
and akinesia with special reference to PD are described as below:
–
An impairment in the initiation of movement
–
Delay in the reaction time
–
Decreased ability to stop the movement once it is started
–
Lack of spontaneous or associated movements, e.g. arm swinging during walking
–
Abnormally small amplitude movements, e.g. small steps during walking or
micrographia,
i.e.
reduction in the size of the written word
–
Complex movements are more involved than simple movements
–
Internally generated movements are more affected than those which occur in
response
to
sensory stimuli
–
Difficulty in performing two separate movements simultaneously
–
No advance planning for the next movement while the present movement is in
progress
–
Repetitive movements show a decrease in amplitude and ultimately fade out.
• Rigidity:
Rigidity is one of the cardinal features of Parkinsonism. Clinically, it is
defined as
an
increased resistance to stretch and the inability to achieve complete muscle
relaxation.
The
features of rigidity with special reference to PD are described as below:
–
Rigidity is not due to an increase in gamma motor neuron activity, a decrease
in recurrent
inhibition
or a generalized excitability in the motor system.
–
Excessive and uncontrollable supraspinal drive to alpha motoneurones is the
most important
cause
of rigidity in PD.
–
Rigidity might increase energy expenditure. This may be perceived as increased effort
on
movement or the feeling of post exercise fatigue.
• Postural
instability: Postural instability is the hallmark of stage III disease.
Patient becomes
more
and more flexed as the condition deteriorates.This results into reduced
rotation and
forward
shifting of center of gravity and makes the patient more prone to falls. There
are
balance
difficulties, even when the patient is seated. More than 1/3 of all patients
with PD
fall
and over 10 percent fall more than once a week.
• Gait:
The characteristic features of the gait of parkinsonian patient are shortened
stride,
festination,
loss of arm swing and increased cadence. Patients take increasingly fast but
short
steps in order to position their lower limbs under their flexed trunk. Instead
of a heeltoe
progression
there may be a flatfooted or, with disease progression, a toe-heel sequence.
This
results into the decreased ability to step over obstacles or to walk on
carpeted surfaces.
• Other
symptoms: Several other symptoms are also associated with PD. For example:
– Mask like face
–
Reduced blinking of the eyes
–
Slowing of speech with a decrease in volume
–
Cognitive changes such as depression or dementia
–
With the progression of the disease other symptoms may get involved. For
example,
pulmonary
infection or gastrointestinal dysfunction such as dysphagia and constipation
or autonomic dysfunction such as postural hypotension
Evaluation
and Assessment
•
PD is revealed by itself over the time
•
The diagnosis is based on history and physical examination
•
No laboratory or imaging studies are available to diagnose PD
•
Physical examination should focus on the degree of tremor, bradykinesia,
rigidity, balance
and
gait impairments
•
The overall disability can be evaluated by using Parkinson’s disease evaluation
form34
Management
• Pharmacotherapy:
–
The aim of pharmacotherapy is to provide the symptomatic relief by replacing or
compensating for lost dopaminergic neuron activity.
–
No drug is capable to delay disease progression
–
With mild severity of disease, it is better to delay pharmacotherapy until
symptomatic relief is needed
–
Levodopa is the most commonly used drug in the treatment of PD
–
Dopamine agonists are most commonly used as an adjunct to levodopa.
• Nonpharmacotherapy:
–
Education to patient and care-givers includes the thorough explanation of the
progressive
nature of the disease as well as the importance of home exercise
program.
– Nutrition:
i.
A high-fibre diet and sufficient fluid intake to reduce the severity of constipation,
which
is a common complaint in PD.
ii.
Calcium and vitamin D supplementation to improve bone health.
iii.
Protein restriction, especially in later stages of the disease, to reduce amino
acid
competition
with levodopa for absorption.
–
Speech therapy to assist tongue dysfunctions and improve voice volume
Physical
therapy: Although, therapeutic intervention
can not halt or reverse the progressive
disability,
it helps in enhancing the quality of life throughout the course of disease.
Thus, early
and
ongoing physiotherapeutic intervention is essential to prevent secondary
complications and
maintain
function in PD. Physical therapist should determine the causative factors and
then
administer
the appropriate treatment strategies to attain the status of maximum functional
independence.
• Relaxation
techniques: This is a vital component of treatment program with an aim to
reduce
rigidity. Physical therapist should remember that unless and until the rigidity
is reduced,
it
is difficult to initiate the movements. In addition to it, relaxation
techniques may help in
reducing
the tremor. The techniques used may be:
i.
Gentle, slow rocking movements
ii.
Rotation of extremities and trunk
iii.
Savasana
iv.
Biofeedback
v.
PNF techniques
• Active
ROM and stretching exercises: These are especially important in the earlier
stages of
PD,
to prevent shortening of muscle because in PD, the contractile elements of
flexor
muscles
become shortened, whereas those of the extensor muscles become lengthened.35
Scapular
and pelvic mobility should be given special emphasis. Physical therapist should
remember
that
i.
Sitting is the better starting position then supine lying because rigidity may
be increased
in the later position.37
ii.
Movements should be started first in distal joints and then progression can be
made for
more
proximal joints. This is because trunk and other proximal muscles are more
involved
than
the distal muscles.
iii.
Movements performed should be large, simple and through the full range.
iv.
Rhythm or music may facilitate the movement.
v.
It is easier to perform the movements in bilateral symmetrical patterns rather
than
reciprocal
patterns. For example, arm swinging.
vi.
Progression may be made by performing movements in diagonal pattern.
vii.
Stress, fatigue, anxiety or need to hurry may exacerbate the freezing
associated with
PD.
• Breathing exercises: As the
patients of PD adopt a more flexed posture, the chest expansion
is
reduced. Moreover, the most common cause of death in these patients is
pneumonia.
Thus,
breathing exercises are very important and should be incorporated at all stages
of PD
to
maintain vital capacities and prevent pulmonary complications. The exercise may
range
from
simple chest expansion exercise to specific breathing exercise.
• Strengthening exercises:
Muscular weakness is not the main feature of PD. However, strength
may
be decreased due to disuse. Hence, strengthening exercises should be included
in the
treatment
program of PD. In addition to it, strengthening exercises may help to prevent
falling.
Physical therapist should remember that functional strength training is more
effective
than
weightlifting in improving muscular strength in the patients of PD.38 Special
attention
should
be paid to extensors of trunk so as to counteract the flexed posture that
develops in
these
patients.
• Mobilization techniques: There
is a tendency to have the limitations in the range of ankle
dorsiflexion,
knee flexion and extension, hip extension, spine extension and rotation of
trunk
as
well as both extremities. Hence, mobilization techniques are essential for the
patients of
PD
to improve ROM. However, it should be remembered that conditions such as
osteoporosis
may
results into an injury, if vigorous mobilization is done.
• Aerobic exercise: The patients
of PD can participate in aerobic exercise without increasing
the
disease activity. However, as far as the intensity of exercise is concerned, it
is reported
that
vigorous aerobic exercise is beneficial in the earlier stages, whereas a
carefully structured
low-impact
aerobic exercise is beneficial for the patients who are in the later stages of
disease.
The benefits may include:
i.
Improvement in vital and aerobic capacities34
ii.
Improvement in immunological function41
iii.
Improvement in gait and balance42
iv.
Reduction in dysfunction43
• Proprioceptive neuromuscular
facilitation: In PD, a dominance of flexor muscle group
leads
to an impairment of rotation because rotation is dependent upon balanced
activity
between
flexor and extensor muscle groups. This suggests that technique of PNF, in
which
rotatory
component acts as the holding or stabilizing group, should be used in these
patients.
In
“normal timing” rotation initiates the movement, giving stability and direction
to the
pattern. Following this, movement takes place at the distal
joints.56 This sequence is particularly
helpful
because, as discussed earlier, proximal muscles are more involved than distal
muscles
in
Parkinson’s disease. All patterns of PNF should be administered, but trunk
patterns are
the
essential movements as trunk rotation helps in reducing proximal rigidity.36
Fig. 9.25
shows
the use of symmetrical PNF pattern to take off the shirt by the patient
himself.
• Postural correction: Patients
with PD may have a more flexed posture both due to the CNS
pathology
and the ageing process. Thus, postural correction should be directed towards
the
attainment
of an extended, upright posture. The following techniques may be used:
i.
McKenzie’s technique
ii.
Passive stretching of flexor muscle groups
iii.
Strengthening of extensor muscle groups
• Balance training: This should be
started at the early stage of the disease. The training
should
include
i.
Self-induced displacements
ii.
External displacements
iii.
Equilibrium reactions at various speeds and in all directions
iv.
A variety of task-specific activities
However,
in the technique of rhythmic stabilization, the direction of resistance should
be
changed
gradually. This is to allow sufficient time so as to develop force in one set
of muscles
before
switching over to other set of muscles. Physical therapist must remember that
if proper
timing
is not allowed to a patient of PD, the already inefficient, ineffective
patterns of motor
activity
may be reinforced.
• Transfer training: This is one
of the major problems with the patients of PD. Because
transfer activity is the complex task and primary problem of
these patients is the difficulty
in
motor planning. Thus, to make it easier to perform these tasks, physical
therapist should
train
them on the basis of following guidelines:
i.
The complex task should be broken down into simple components
ii.
Rolling over in bed should include trunk rotation
iii.
To get out of the bed, patient should learn to roll onto one side and then to
lower the hips
off
the bed
iv.
Lateral and anerior/posterior tilts in sitting position should be practiced
first to facilitate
the
functional task of standing from sitting
v.
The warmth of an electric mattress will reduce the need of covers, which in
turn, may
make
the bed mobility easier
vi.
Satin sheets with satin dress will also make the bed mobility easier
vii.
The verbal and physical cuing may provide guidance to patient
viii.
In later stages when mobility becomes very difficult, the assistance may be
provided
manually
by the care-taker or with the help of bed rails, a lift chain or a commode with
arms.
• Gait
training: Physical therapist should design a comprehensive gait training
program so as
to
reduce the main problems of gait such as lack of rotation, loss of arm swing,
“freezing”
and
small steps. Thus, the program may include:
i.
The movement of rotation of upper trunk, lower trunk and upper extremity.
Examples
of
such movements are displayed in Fig. 9.24.
ii.
Rhythmical alternate movements of arm flexion and extension. This may be done
in
sitting
to initiate arm swing (Fig. 9.26).
iii.
Exercises that can improve extension and reduce flexed posture. This is to
superimpose
arm
swing in an automatic manner. Because even in normal individuals, arm swing
which
is a passive action occurs as a result of interaction between the pelvis and
shoulder
girdles
on the basis of an extended upright posture.
iv.
Auditory stimulation. Use of appropriately synthesized music during walk may
improve
stride
length and speed.39
v.
Visual stimulation. This can be provided by asking the patient to walk on the
parallel lines
drawn
on the floor with a gap in between (Fig. 9.27) which may help to cope with
freezing
episodes.40
vi.
No assistive device. This is because at times, it may increases a festinating
gait.
vii.
Progression. This may be made by gait training
–
on steps
–
in crowds
–
through doorsteps
–
with different speeds and
–
with different stride lengths
• Surgical therapy:
– Pallidotomy:
The surgical destruction of globus pallidus is helpful in relieving the
contralateral
drug-induced dyskinesias in most of the patients.
– Deep
brain stimulation: Deep brain stimulation of globus pallidus may be
effective in
improving the motor symptoms of PD.
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