KIN 312 Midterm

Winter 2025 with Bill McIlroy

Neurological Disorder

a disease or injury to the central or peripheral NS which could include:

• brain or brainstem

• spinal cord

• peripheral nerves

• neuromuscular junctions

Neurological disorders may be the result of:

• injury/trauma/autoimmunity

• structural abnormalities

• biochemical imbalances

• electrical conduction/impulse problems

Levels of Burden

there are 4 main ones

• financial

• health care

• personal

• caregiver

Financial Burden

• cost of treatment

• loss of work potential

• assistance cost

• ODSP (disability)

Health Care Burden

• time it takes to diagnose

• diagnostic/personnel resources

• long term medical needs (e.g. infrastructure)

Personal Burden

• losing years of healthy living

• impairment

• functional limitation

• disability

• financial

• mental health

Caregiver Burden

• physical, mental, emotional burden

• financial/work impact

• social disengagement

Prevalence

proportion of people who have X condition at a specific point in time (e.g. everyone who has it right now)

Incidence

the rate or proportion of people who will develop condition X during a particular time period (e.g. stroke is 0.14% per year)

Control of Movement

it is the process by which the human nervous system controls muscles to produce movement

• interactions of muscles, joints, NS

• needs planning, coordination, action, feedback, and adaptation

requires the control of posture from many systems and many levels in the CNS

Criteria of Healthy Movement

• successful in space and time

• smooth and coordinated

• efficient (minimal energy needed)

• adaptable

• avoid injury

Postural Control in Movement

• movement often have a clear purpose

• some muscles contribute directly to the purpose

• postural muscles are needed to control body position and stability

Adaptability

real capacity of the healthy motor control system to adapt to environmental demands

• quick for solving immediate challenges (min or less)

• long-term adaptations like learning a new skill (hours to months)

Building Blocks of NS

neurons and glial cells linked together in an organized manor needed for sensation, movement, cognition, regulating body systems

Neuron

for structure and for function, specialized for rapid communication

• cell body with dendrites

• axon and axon terminals (tracts in CNS, nerves in PNS)

• dendrites for input

• axon hillock for firing

• myelin sheath for insulation and conduction (schwann cells in PNS, oligodendrocytes in CNS)

Functional Classification of Neurons

sensory (afferent): input from special endings to sense stimuli → output to neuron

motor (efferent): input from neuron → output to muscle

interneuron: input from neuron → output to neuron

Neuroglia

used for:

• physical support

• regulation (growth, development, repair, metabolic support)

• insulation - myelin

• homeostasis - nutrients, O2, chemical gradients

• pathogen removal

• synaptogenesis and plasticity

CNS Neuroglia

astrocytes (regulation of neuronal excitability, homeostasis, repair + plasticity)

oligodendrocytes (myelinated and insulate + propagate signals)

PNS Neuroglia

Schwann cells (glial cells that make myelin for a single neuron)

satellite cells (non-myelinating cells that make a supportive capsule around nerve soma in the ganglia)

Saltatory Conduction (within neuron)

myelin sheath on axon doesn’t have ion pumps or channels; nodes of Ranvier have concentrated Na/K pump and channels

action potential jumps between nodes and refreshes after the jump because of voltage decay

without myelin the signal wouldn’t go through even with firing → nerve block

Conducting Information Between Neurons

synaptic transmission (chemical signals)

action potential at synapse → calcium channels open + enters cell → vesicles release neurotransmitter into synapse → neurotransmitter reaches post-synaptic cell

CNS Terminology

nuclei - bundle of cell bodies

tract - bundle of axons that connect nuclei

cell bodies - grey matter (unmyelinated)

axons - white matter (myelinated)

Spinal Cord

entry + exit to PNS with ascending (towards brain) and descending (away from brain) fibre tracts

interneurons - found in spinal cord and brain to relay signals between sensory and motor nerves

• cervical spinal cord - 7 vertebrae, 8 spinal nerves

• thoracic spinal cord - 12 vertebrae, 12 spinal nerves

• lumbar spine - 5 vertebrae, 5 spinal nerves, conus medularis

• sacral spine - 5 fused segments, 5 spinal nerve roots

Basal Ganglia

group of subcortical nuclei that is connected to cortex, thalamus, and brain stem

includes:

• putamen

• caudate

• globus pallidus

• subthalamic nucleus

• substantia nigra

controls action selection and procedural learning and plays a role in cognition and emotions

Cerebral Cortex

frontal lobe - decision-making, attention + impulse control, action selection, motor control

parietal lobe - somatosensory processing, visuospatial map → primary somatosensory cortex, motor control

temporal lobe - memory, auditory and language processing, emotions → primary auditory cortex

occipital lobe - visual processing → primary visual cortex

Functional Division of NS

somatic NS - afferent and efferent nerves

Structural Division of NS

autonomic - sympathetic (fight or flight) and parasympathetic (rest and digest) systems

Motor Unit

consists of the alpha motor neuron and all of the muscle cells it connects to

motor neuron - nerve that activates muscle fibres (damage here allows for neurogenesis)

all or none rule applies here and more motor units recruited = bigger contraction

Upper Motor Neuron

cell body in cortex, synapses onto motor neuron

axon travels in the corticospinal tract to synapse on lower motor neuron

Lower Motor Neuron

cell body in spinal cord or brain stem and has axon that directly innervates muscle fibres

Akinesia

inability to initaite movement

dyskinesia

abnormal movement. difficulty controlling movement

Hypokinesia

decreased or weirdly diminished movements

Hyperkinesia

exaggerated or increase in movement

Bradykinesia

abnormal slowness of movement (note the difference between abnormal and compensatory)

Types of Hyperkinesia

could also be categorized as dyskinesias

• chorea: ongoing, brief, irregular, asymmetrical, involuntary movement (looks dance-like, discussed in Huntington’s)

• athetosis: slow continuous writhing/wringing that often involves distal limbs (e.g. hands and feet)

• tics: sudden. repetitive, non-rhythmic, stereotyped movement including vocalizations

• myoclonus: sequence of repeated, brief, involuntary shock-like jerks from involuntary muscle contraction/relaxation

Reflexes

hyperreflexia: exaggerated reflexes

hyporeflexia: diminished reflexes

areflexia: no reflexes

note: you can have akinesia but not areflexia and vice versa because reflexes are INvoluntary

Dystonia

abnormal muscle tone

symptoms: sustained contractions causing twisting, repetitive movements, abnormal posture

Hypertonia

abnormal increase in muscle tension at rest and reduced ability of a muscle to be stretched

spasticity

Hypotonia

abnormal decrease in muscle tone at rest - less muscle resistance

NOT the same as muscle weakness

Spasticity

excessive muscle tone whose magnitude is dependent on passive stretch velocity

Clonus

series of involuntary contractions from sudden stretching of the muscle (involuntary resistance when stretched) - common in ankle

form of hypertonia and hyperreflexia

Contractures

permanent shortening of muscle/tendon due to excessive tone

form of hypertonia

Hemiplegia

paralysis of one side of body

Paraplegia

paralysis of LOWER limbs

Quadriplegia/Tetraplegia

paralysis of four limbs

Hemiparesis

weakness on one side of body - affects ability to generate force

common symptom of stroke

Myopathy

muscular disease caused by primary defect within the muscle

could be neuromuscular or musculoskeletal

Neuropathy

damage to PNS like in sensory, motor, and/or autonomic fibres

Paresthesia

sensation of tingling, prickling, or numbness of skin (basically abnormal sensation)

Ataxia

lack of order of movement (coordination), movements characterized by discoordination that is not explained by loss of sensation or weakness

Apraxia

inability to do learned purposeful movements (work) that is not explained by loss of sensation, weakness, or coordination

basically can’t execute an intended, voluntary behaviour

Components of a Neurological Assessment

a combination of:

1. subjective report (what’s going on)

2. mental status/screening questions

3. objective exam

4. lab testing (blood work e.g.)

5. neuroimaging

6. electrophysical testing

Objective Assessment: Sensation

used to determine the type and location of sensory impairment

usually starts with a screen with multiple modalities - light touch, pain (sharp/dull) or temperature (hot/cold), proprioception (sense of body position) or vibration

dermatomal testing

area of skin supplied by a single nerve root tested to where the impairment comes from

Myotome Testing

a muscle/group of muscles supplied by a single nerve root

single nerve root lesion is usually associated with paresis of the myotome supplied by that nerve root