Motor Disorders

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Motor Disorders

• Motor disorders affect either the cell body of
  the motor neuron in the CNS, the axon of the
  motor neuron that runs into the PNS, the
  neuromuscular junction, and or muscle cells.
• Disorders are distinguished based on symptoms and
  which of these components is affected.

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Motor Disorders

• Disorders are further distinguished based on
  being disorders of upper motor neurons, motor
  neurons wholly in the brain and which synapse on
  lower motor neurons.
• Other disorders are of lower motor neurons,
  neurons of the lower brain and or spinal cord
  which extend axons into the PNS and synapse on
  muscle.

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Motor Disorders

• Classified as neurogenic diseases or neuropathies
  that either affect the motor neuron cell bodies
  vs. those that affect peripheral axons
  (peripheral neuropathies) produce little
  degeneration of muscles.
• Myopathic diseases involve degeneration and
  wasting away of muscle fibers with little change
  in neurons or axons.

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Signs of Disorder

• Deep tendon reflexes (DTRs) such as the knee jerk
  are normally uniform in all limbs with disorders
  their activity, symmetry or both will be altered.
• In general, CNS damage results in hyperactive
  DTRs whereas with peripheral damage, DTRs are
  hypoactive.

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Pathological Reflexes

• Pathological reflexes, a common sign of CNS
  damage is the Babinski sign, a reflex normally
  not seen in individuals over age one. In normal
  cases over age one, stimulation of the sole of
  the foot produces a flexion of the big toe
  downward. With brain or spinal cord damage, the
  same stimulation produces an extension of the big
  toe, it moves upward, termed the Babinski sign.
  Babinski signs are termed present or elicited but
  not positive or negative

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Signs

• Upper motor neuron signs include, paresis
  (mild/moderate weakness) with muscle spasticity,
  hyeractive DTRs, Babinski sign
• Lower motor neuron signs include paresis with
  muscle flaccidity, no Babinski sign

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Tremors

• A simple involuntary movement consisting of a
  rhythymic, oscillations of a body part about a
  fixed point, can occur in any part of the body
  served by skeletal muscles.

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Types of Tremors

• Normal physiological at-rest tremor, a product of
  mechanical effects arising from the beating of
  the heart.
• Normal physiological action or postural tremor,
  also some input from beating heart,
  synchronization tendencies of spinal reflexes,
  mechanical springiness of muscles, tendons, etc.,
  interactions between firing patterns of
  antagonistic muscles maintaining a posture

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Essential Tremor

• A tremor that often occurs in families as a
  autosomal dominant trait. Frequency ranges from
  4-9 Hz, may occur in childhood or only later in
  life and typically runs a slowly progressing
  course.
• Usually postural but in some it increases with
  kinetic movement, rarely persists at rest, most
  commonly occurs in distal upper extremities,
  individual fingers may be affected

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Essential Tremor

• The head can be affected, vocal tract likewise
  which can give a wavering quality to the voice.
• Essential tremor interferes with daily activities
  such as shaving, drinking from a cup, using
  utensils alcohol is very effective at
  suppressing essential tremor but it worsens when
  the alcohol wears off.

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Intention Tremor

• In reaching for an object, the persons reach
  stops too soon or too late as they undershoot and
  overshoot the target, back and forth several
  times until they can eventually put their hand on
  the target object.
• Indicative of damage to the cerebellum

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Parkinsons Disease

• Parkinsons disease (PD) involves muscle
  rigidity, resting tremor, slowed laborious
  movements.
• The muscle rigidity is seen in a movement of a
  limb which moves stiffly and rigidly and then
  gives way abruptly, termed cog-wheel rigidity.
  The person has a mask-like face and a staring
  expression. With the rigidity the person has an
  inability to initiate a movement, termed
  akinesia. Once a movement is initiated, the
  person has difficulty shifting to another
  movement.
• The person may only be able to initiate a
  movement under idiosyncratic stimulus conditions,
  such as only being able to take a step if a
  barrier is placed in front of the patients
  foot.. The rigidity of the muscles in the hands
  may cause the persons handwriting to become
  smaller and smaller termed micrographia.

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Parkinsons Disease

• Pill rolling tremor or tremor at rest with
  frequency of 3 to 7 Hz.
• Tremor disappears or diminishes with the
  initiation of a movement but later on in the
  condition may return with a maintained posture

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Parkinsons Disease

• The afflicted person often cannot extend their
  arms to break a fall or adjust their posture to
  avoid a fall, hence postural instability is a
  major symptom.
• The tremors are seen in a limb at rest which will
  diminish somewhat as the limb is moved, hence, a
  resting tremor is said to be present in the
  limbs. In the hands, the tremor often takes the
  form of the thumb rolling over the first two
  fingers as if the person were rolling a pencil or
  a pill back and forth in their hand, or this is
  termed the pill-rolling tremor. The persons
  head or lower lip will also show the tremor.

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Parkinsons Disease
The motoric symptoms of Parkinsons are
sometimes termed T tremors R rigidity A
akinesia P postural instability Parkinsons is an
example of hypokinetic symptoms, a feature of
basal ganglia disorders. Basal ganglia disorders
typically involve either inhibition of voluntary
movements or the initiation of involuntary
movements
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Parkinsons Disease
Early non-motor symptoms include Up to 40 have
subjective somatosensory complaints including
pain, tingling, numbness or burning in body
areas prior to TRAP. Up to 75-90 have a
significant reduction in olfactory acuity or
hyposmia. Later non-motor symptoms include 1 in
4 become demented
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Parkinsons Disease

• Stage One
• 1.Signs and symptoms on one side only
• 2.Symptoms mild
• 3.Symptoms inconvenient but not disabling
• 4.Usually presents with tremor of one limb
• 5.Friends have noticed changes in posture,
• locomotion and facial expression
• Stage Two
• 1.Symptoms are bilateral
• 2.Minimal disability
• 3.Posture and gait affected
• Stage Three
• 1.Significant slowing of body movements
• 2.Early impairment of equilibrium on walking
  or standing
• 3.Generalized dysfunction that is moderately
  severe

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• Stage Four
• 1.Severe symptoms
• 2.Can still walk to a limited extent
• 3.Rigidity and bradykinesia
• 4.No longer able to live alone
• 5.Tremor may be less than earlier stages
• Stage Five
• 1.Invalidism complete
• 2.Cannot stand or walk
• 3.Requires constant nursing care

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Huntingtons Disease
Huntingtons disease (HD) involves
uncontrollable, jerky movements of the limbs
also known as Huntingtons chorea, from a Greek
word for dance but think of slam dancing to
properly envision Huntingtons. The movements
consist of chorea, sudden movements of the limbs
which can be violent and dramatic. Athetosis or
slow sinuous, writhing movements, especially
severe in the hands performed involuntarily, an
inability to to sustain the fingers, toes, tongue
or other group of muscles in any one position,
resulting in grotesque changing postures A
disorder of hyperkinetic symptoms of the basal
ganglia
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• Symptoms
• - onset is insidious
• - psychiatric disturbances, personality changes
  of apathy irritability to full-blown
  manic-depressive or schizophreniform illness
• - psychiatric disturbance preceding or
  concomitant with movement disorder
• - motor manifestations include flicking movements
  of the extremities, lilting gait, and motor
• impersistence (inability to
• sustain a motor act)
• - facial grimacing, ataxia, and
• dystonia may also appear

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Tourettes Syndrome

• Tics of the limbs, face and head, and involuntary
  vocalizations, usually simple vocal tics such as
  inarticulate sounds, complex vocal tics can be
  the involuntary and compulsive utterances of
  obscenities (copralalia) performing obscene
  gestures (coprapraxia) or the intrusion of
  obscene thoughts (mental copralalia , animal
  sounds, repeating the utterances of others,
  possibly imitating the actions of others such
  facial expressions, but in extreme caricature.
• A basal ganglia disorder of hyperkinetic symptoms

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Multiple Sclerosis

• Multiple sclerosis (or MS) is an autoimmune
  disorder in which immune system cells in the CNS
  attack and breakdown myelin on CNS axons.
• A myelinated axon stripped of its myelin ceases
  to function. As the loss of myelin progresses,
  loss of sensory and motor functions result, with
  the loss of motor functions being more dramatic
  and obvious.
• The symptoms may be sporadic with remissions and
  periods of improvement but the person inevitably
  declines. MS is fatal.

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• MS
• - progressive disease of CNS myelin
• - onset in early adulthood
• - gradual destruction of myelin sheaths
• - accompanying development of hard scar tissue
  (sclerosis)
• - occasional (and sometimes long-lasting)
  remissions
• - thought to result from autoimmune dysfunction.
• Symptoms in advanced MS
• - muscular weakness, tremor,
• urinary incontinence, numbness
• visual disturbances, ataxia (loss of
• motor coordination)

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Myasthenia Gravis

• Severe muscle weakness and eventual paralysis,
  thought to be due to an autoimmune disorder of
  the acetycholine receptor at the neuromuscular
  junction, prevents muscle fibers from
  depolarizing. Most patients have antibodies for
  the ACh receptor
• May begin in the occular muscles, severe drooping
  of the eyelids, (ptosis) and double vision
  (diplopia), progresses to more and more muscle
  weakness, nasal speech, difficulty in swallowing
  and articulation

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MG

• Symptoms are progressive with fatigue but
  interspersed with periods of no symptoms or
  apparent recovery of abilities and then symptoms
  reappear. Symptoms much better after sleep or
  rest. If physical exerted or stressed symptoms
  much worse.
• Visible symptoms include fasciculations, visible
  twitches of muscle, seen as moving ripples under
  the skin occur in a single motor unit, result
  from involuntary but synchronous contractions of
  enervated muscle fibers, characteristic of
  degenerative motor neuron conditions

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MG

• 90 of patients first complain of diplopia or
  ptosis may grimace when smiling due to weakness
  of facial muscles.
• During sustained upward gaze, occular weakness
  becomes apparent in a lengthy conversation
  speech becomes more and more nasal sounding
• In moderately advanced cases, neck shoulder and
  respiratory become weak, in severe cases apnea
  develops and quadriplegia renders the person
  locked in

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Apraxia is the inability to perform movements in
response to commands and results from
disconnection or destruction of dominant
hemisphere association areas
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• Apraxia is divided into various types ideomotor,
  ideational, limb-kinetic, constructional, ocular,
  gait and dressing. Ideomotor (motor) apraxia is
  the principal form and is often referred to
  simply as apraxia.
• Ideomotor apraxia may involve buccofacial, limb
  or truncal (axial) musculature.

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• Buccofacial apraxia is tested by asking the
  patient to imitate various motor acts, including
  Blow out a match, Drink with a straw, or
  Stick out your tongue.
• One should look for incomplete, unrelated or
  opposite motor acts. For example, the patient
  may inhale while blowing out the imaginary match.

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• Limb apraxia can involve the upper or lower limbs
  and may be unilateral. Therefore, all four
  extremities should be tested. Test by asking the
  patient to Salute with your left hand, Put out
  a cigarette with your left foot, Kick a ball
  with your right foot, and Brush your teeth
  holding the imaginary toothbrush with your right
  hand. Observe for such errors as the use of a
  finger for the toothbrush or failure to open the
  mouth.

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• Truncal apraxia is tested with commands such as
  bow or stand like a boxer.

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• Sympathetic apraxia is a left hemisphere lesion
  in the motor association areas or white matter
  disconnects motor regions of the two hemispheres.
  As a result, fibers from the motor areas of the
  dominant hemisphere do not reach the non-dominant
  motor cortex. Patients are unable to carry out
  commanded movements with their non-hemiplegic
  left arm.

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• Callosal apraxia is related to sympathetic
  apraxia and usually results from a lesion in the
  anterior corpus callosum disconnecting the motor
  areas of the two hemispheres. In callosal
  apraxia, patients are unable to perform movements
  on command with their left arm or leg, although
  they execute commands easily with right-sided
  limbs

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• Ideational apraxia refers to a disruption in the
  logical and harmonious succession of separate
  elements in a movement. Patients with
  ideational apraxia may successfully perform
  individual components of a complex sequence, but
  fail to execute the correct series of actions.

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• Limb-kinetic apraxia refers to the loss of fine,
  skilled movements following premotor lesions.
  Patients are clumsy, slow and awkward in
  executing motor tasks that were performed more
  rapidy and precisely prior to cerebral insult.

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• Constructional apraxia is better described as
  visual-spatial agnosia. Constructional apraxia
  is tested by having the patient copy or
  spontaneously draw figures, arrange blocks in
  patterns, and construct or mentally manipulate
  three-dimensional structures.

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• Apraxia refers to an acquired inability to
  properly execute a learned skilled movement
  following brain damage
• Limb apraxia involves movement of the wrong
  portion of a limb, incorrect movement of the
  correct limb part, or an incorrect sequence of
  movements
• Callosal apraxia person cannot perform movement
  of left hand to a verbal request (anterior
  callosum interruption prevents information from
  reaching right hemisphere)
• Sympathetic apraxia damage to anterior left
  hemisphere causes apraxia of the left arm (as
  well as paralysis of right arm and hand)
• Left parietal apraxia difficulty in initiating
  movements to verbal request, in both limbs
• Constructional apraxia is caused by right
  parietal lobe damage
• Person has difficulty with drawing pictures or
  assembling objects