PSYC 301 Disorders of Movement

Corticospinal tract function

Voluntary motor control of the trunk and limbs

Superior and medial motor cortex representation

Lower limbs

Inferior and lateral motor cortex representation

Upper limbs and face

corticobulbar tract function

Voluntary motor control of the face

Lesion to anterior corticospinal tract before decussation result

Contralateral deficits

Lesion to anterior corticospinal tract after decussation result

Ipsilateral deficits

Lesion to lateral corticospinal tract superior to medulla result

Contralateral deficits

Lesion to lateral corticospinal tract inferior to medulla result

Ipsilateral deficits

Lesion to corticospinal tract lower motor neuron result

Ipsilateral effect

Common effects of lesion to corticospinal tract upper motor neuron

Weakness, increased reflexes, and increased tone

Common effects of lesion to corticospinal tract lower motor neuron

Weakness, atrophy, fasciculations, decreased reflexes, and decreased tone

Fasciculations

Constant involuntary twitching or flickering of muscle fibres

Upper motor neuron-type facial weakness

Eyeball and inferior drooping while eyebrow remains functioning; typical of stroke

Lower motor neuron-type facial weakness

Entire face drooping, including the eyebrows; signals a cranial nerve issue (e.g. Bell's palsy)

Subcortical and cortical areas function in movement

Initial drive to move

Association cortex function in movement

Movement design "rough draft"

Basal ganglia and cerebellum function in movement

Refined movement design

Thalamus function in movement

Relay station

Motor cortex function in movement

Final executor of motor plan

Motor units function in movement

Execution of desired movement

Motor channel input and output

Putamen; motor cortex

Oculomotor channel input and output

Caudate body; frontal eye fields

Prefrontal channel input and output

Caudate head; prefrontal cortex

Limbic channel input and output

Nucleus accumbens, ventral caudate and putamen; anterior cingulate gyrus and orbital frontal cortex

hypokinetic basal ganglia disorders

Akinesia and rigidity; Parkinson's disease

Hyperkinetic basal ganglia disorders

Tremor, chorea, athetosis, tics, dystonia, and myoclonus; Parkinson's disease, Huntington disease, and tourette syndrome

Lesion to lateral cerebellum result

Limb incoordination

Lesion to medial cerebellum result

Trunk and posture problems

Lesions to cerebellum results

Ataxic gait, intention tremor, nystagmus, and scanning speech

Nystagmus

Involuntary, rhythmic movement of the eyes

Scanning speech

Spoken words are broken into separate syllables and varying force/tone behind voice-dysmetria in speech

Akinesia or bradykinesia

Slow movement

Hypertonia

Muscles are stiff

Hypokinetic movement disorders

Weakness, paralysis, akinesia/bradykinesia, and hypertonia

Types of weakness

-paresis, -plegia, and palsy

-paresis

partial paralysis, weakness

-plegia

Complete paralysis

Palsy

Weakness or complete paralysis due to lower motor neuron lesion

Disorders of muscle tone

spasticity and rigidity

Spasticity

velocity dependent resistance to passive muscle stretch

Rigidity

Resistance to passive movement that does not vary with velocity or force

Hyperkinetic movement disorders

Tremor, tics, myoclonus, chorea, and athetosis

Tremor

Rhythmic oscillations caused by intermittent muscle contractions

Tics

Paroxysmal, stereotyped muscle contractions that are temporarily suppressible

Paroxysmal

Sudden recurrence of a fit/attack of symptoms

Myoclonus

shock-like arrhythmic twitches in response to a stimulus, typically affects large muscle groups

Chorea

Dance-like, arrhythmic and unpatterned movements

Athetosis

Continuous writhing movements to maintain postures

Types of tremor

Essential, resting, and action

Essential tremor

Constant, bilateral and symmetric rhythmic muscle contractions; is not seen is acquired neurological disorders

Resting tremor

Rhythmic muscle contractions when skeletal muscle is at rest

Action tremor

Rhythmic muscle contractions during voluntary movement

Types of gait disorders

Spastic/hemiplegic, ataxic, and Parkinsonian

Spastic/hemiplegic gait disorder

Stuff-legged, decreased arm swing on the same side; seen in MCA stroke and cerebral palsy

Ataxic gait disorder

Wide-based, unsteady, and staggering; seen in cerebellar stroke or tumour and alcohol intoxication

Parkinsonian gait disorder

Shuffling and narrow-based; seen in Parkinson's disease, progressive supranuclear palsy, and neuroleptic drugs

Motor schema

An abstract representation of a movement plan, stored in memory, which contains all the motor commands required to carry out the intended action (muscle memory); stored in the left inferior parietal lobule

Praxis

The act of engaging, applying, exercising, or practising something (an idea or movement)

Apraxia

An inability to perform previously learned, sequential motor movement that is not explained by weakness or motor incoordination; patient may not be able to use familiar objects or tools