Neurological System Assessment

Neurological Assessment Overview

• The student will utilize a body systems approach
• Apply relevant concepts from anatomy, physiology, biology, chemistry, psychology, developmental psychology, and sociology to assess the neurological system of adults
• Apply health history and physical examination principles when conducting a holistic assessment
• Conduct and document a health history and physical exam, while applying principles of caring, therapeutic communication, interprofessional communication, and professionalism
• Use genetics and genomics concepts

Objectives

• Interpret lab and diagnostic findings for the neurological system
• Base recommendations for appropriate health promotion and clinical prevention strategies on national guidelines like Healthy People 2030 and AHRQ Clinical Prevention Guidelines
• Assess self and patient scenarios using clinical reasoning
• Demonstrate professionalism in the clinical simulation lab
• This includes honoring confidentiality of scenarios and health histories, respecting self-determination and human dignity, and abiding by lab guidelines on equipment use and dress code
• Describe expected and unexpected findings by body system, including ethnic, cultural, and age variations

Nervous System

• There are three parts:
• The central nervous system that contains the brain and spinal cord
• The peripheral nervous system that contains the cranial and spinal nerves
• The autonomic nervous system which contains the sympathetic and parasympathetic systems

Protective Structures

• The skull protects the brain
• The foramen magnum is a large oval opening at the base of the occipital bone
• The spinal cord extends through the foramen magnum from the medulla oblongata
• Meninges are three layers between the skull and the brain
• The dura mater is the outer double layer
• The arachnoid is the middle meningeal layer
• The pia mater is the inner meningeal layer
• Cerebrospinal fluid (CSF) circulates in the subarachnoid space between the arachnoid and pia mater
• CSF is a colorless, odorless fluid containing glucose, electrolytes, oxygen, water, carbon dioxide, and leukocytes

Brain Anatomy

• The brain consists of the cerebrum, diencephalon, cerebellum, and brainstem
• The carotid arteries supply most of the blood to the brain and branch into the posterior cerebral, middle cerebral, and anterior cerebral arteries

Cerebrum

• The largest part of the brain is the cerebrum
• It consists of two hemispheres, each divided into four lobes:
• Frontal
• Parietal
• Temporal
• Occipital

Frontal Lobe

• Contains the primary motor cortex
• Functions related to voluntary motor activity happen here
• Broca's area, in the left frontal lobe, formulates words
• The frontal lobe also controls intellectual function, self-awareness, personality, and autonomic responses related to emotion

Parietal Lobe

• Contains the primary somesthetic (sensory) cortex
• Receives sensory input such as position, touch, shape, and texture of objects

Temporal Lobe

• Contains the primary auditory cortex
• Wernicke's area, in the left temporal lobe is responsible for comprehension of spoken and written language
• It also interprets auditory, visual, and somatic senses that are stored in thought and memory

Occipital Lobe

• Contains the primary visual cortex
• Receives and interprets visual information

Diencephalon

• Made up of the thalamus, hypothalamus, epithalamus, and subthalamus
• The hypothalamus is important to maintaining homeostasis
• Functions include regulating body temperature, hunger, and thirst It forms autonomic nervous system responses
• It stores and secretes hormones from the pituitary gland

Basal Ganglia

• The function here is balancing the production of two neurotransmitters
• Acetycholine and dopamine create smooth, coordinated voluntary movement

Brainstem

• It is made up of the midbrain, pons, and medulla oblongata
• Midbrain relays stimuli concerning muscle movement to other brain structures
• It contains part of motor tract pathways that control reflex motor movements in response to visual and auditory stimuli
• The pons relay impulses to brain centers and lower spinal nerves
• The medulla oblongata has reflex centers for controlling involuntary functions
• Breathing, sneezing, swallowing, coughing, and vasoconstriction
• Motor and sensory tracts from the frontal and parietal lobes cross from one side to the other in the medulla
• Lesions on the right side create abnormal movement and sensation on the left, and vice versa

Cerebellum

• The tentorium cerebelli separates the cerebellum from the cerebral cortex
• The cerebellum coordinates movement, equilibrium, muscle tone, and proprioception
• Each cerebellar hemisphere controls movement for the same (ipsilateral) side of the body

Spinal Cord

• The posterior (dorsal) column carries sensations of touch, deep pressure, vibration, position of joints, stereognosis, and two-point discrimination
• The lateral spinothalamic tract carries fibers for sensations of light touch, pressure, temperature, and pain
• 31 pairs of spinal nerves emerge from spinal cord

Cranial Nerves

• Twelve pairs of cranial nerves exist
• Five pairs have only motor fibers
• Three pairs have only sensory fibers
• Four pairs have both motor and sensory fibers

Reflex Arcs

• These responses are tested by observing muscle movement in response to sensory stimuli
• Deep tendon reflexes are responses to stimulation of a tendon that stretches neuromuscular spindles of a muscle group
• Striking a deep tendon stimulates a sensory neuron that travels to the spinal cord
• This neuron stimulates an interneuron, which stimulates a motor neuron to create movement
• Superficial reflexes are tested similarly
• Each reflex corresponds to a specific spinal segment

Autonomic Nervous System (ANS)

• Sympathetic nervous system is responsible for fight or flight
• Parasympathetic nervous system dominates during calm, non-stressful times
• Sympathetic nervous system (SNS) arises from thoracolumbar segments of spinal cord and is activated during stress
• Increases blood pressure and heart rate, performs vasoconstriction of peripheral blood vessels, and inhibits gastrointestinal peristalsis
• Parasympathetic nervous system (PNS) arises from craniosacral segments of the spinal cord and controls vegetative functions
• PNS actions conserve energy:
• Decreases heart rate and force of myocardial contraction
• Decreases blood pressure and respiration
• Stimulates gastrointestinal peristalsis

Neurotransmitters

• These communicate messages from one neuron to another or from a neuron to a specific target tissue
• They excite or inhibit the target cell's activity
• Usually, multiple neurotransmitters work in the neural synapse
• Examples include dopamine, serotonin, GABA, and epinephrine

Functional Organization of the Brain

• Functions are localized in different parts of the brain
• Multiple systems can overlap
• Assessment can be performed via various techniques (physiology, imaging, neurological exam, neuropsychological exam)
• The two halves of the brain are not exactly alike (brain lateralization)
• Some functions' neural mechanisms are localized in one hemisphere (functional specializations)

Left Brain vs. Right Brain

• Left brain functions:
• Logical
• Sequential
• Rational
• Analytical
• Objective
• Looks at parts
• Right brain functions
• Random
• Intuitive
• Holistic
• Synthesizing
• Subjective
• Looks at wholes

Broca's Aphasia vs. Wernicke's Aphasia

• Broca's aphasia prevents a person from producing speech
• Person can understand language
• Words are not properly formed
• Speech is slow
• Wernicke's aphasia causes a loss of the ability to understand language
• Person can speak clearly, but the words that are used do not make sense
• Speaking this way is called a "word salad" because it appears that the words are all vegetables in a salad

Neurological Exam: Health History

• Health history involves information on prenatal or birth events
• Exposures to toxins or drugs are important
• Illnesses (e.g., Epstein-Barr, Bell's Palsy, Rocky Mountain Spotted Fever, Lyme disease, encephalitis) should be noted
• Injuries (concussion, closed head) are important
• Clinical manifestations or symptoms should be assessed
• Abnormal sensation
• Dizziness
• Visual or sensory disturbances
• Tremors or motor tics
• Pain
• Weakness
• Seizures
• Note diseases like amyotrophic lateral sclerosis, Parkinson's, Multiple Sclerosis, seizure disorders, tumors, Tourette syndrome, myasthenia gravis, migraine, neurofibromatosis, Guillain-Barré Syndrome, Alzheimer's, and muscular dystrophy in the family history

American Academy of Neurology

• Mental status involves level of alertness and orientation
• The exam checks cranial nerves, motor system, sensory system and reflexes (DTRs, plantar)

Mental Status Assessment

• Orientation to time, place, and person
• If there is a concern during history, determine if oriented to time, place, and person
• Date and time is the first orientation to disappear
• Only a problem if the patient remains disoriented being reoriented
• Place is the second orientation to disappear
• Person is the last orientation to disappear
• Orientations return in the opposite order to which they were lost
• Check appearance, general behavior
• Assess thought content, memory
• Check intellectual/functional abilities

Level of Consciousness

• Altered level of consciousness can be determined if the client is alert and oriented by their answers to interview questions
• Change in LOC is the earliest and most sensitive indicator of alterations in cerebral function
• Awareness is a higher level function controlled by the reticular activating system
• Wakefulness is controlled by brain

LOC Categories of Arousal

• Alertness
• Lethargy
• Obtunded
• Stupor
• Coma
• Glasgow Coma Scale assesses LOC using a 15-point scale
• Assess for best response to eye opening, motor response, and verbal response
• Determine stimulation/pain required to elicit response
• Only time pain stimulus is used

Abnormal Posturing

• Decorticate the arms and wrist are flexed, and the legs are internally rotated. Problems with cerebral hemisphere, spinal tract
• Decerebrate has extended arms and legs, pronated arms, flexed wrists, Problems within midbrain or pons

Cranial Nerves

• There are twelve cranial nerves
• I Olfactory - Smell (not usually tested)
• II Optic - Visual acuity
• III Oculomotor - Opening of eyelids, eye movement (upward/medial, upward/lateral, medial, downward/lateral)
• IV Trochlear - Eye movement (downward/medial)
• V Trigeminal - Facial sensation, chewing movements
• VI Abducens - Eye movement (lateral)
• VII Facial - Facial muscle movement (except chewing muscles) and eyelid closing
• VIII Auditory (vestibulocochlear) - Hearing and balance
• IX Glossopharyngeal - Taste on the posterior third of the tongue (not usually tested)
• X Vagus - Uvula (palate muscles) and swallowing
• XI Accessory - Shoulder shrug
• XII Hypoglossal - Tongue movement

Cranial Nerve Abnormalities

• I- anosmia
• II- defect in vision
• III, IV, VI- pupil abnormalities, EOM abnormalities
• V- absent touch & pain, no blink, weakness of masseter or temporalis
• VII- asymmetrical facial movements, loss of taste
• VIII- decrease or loss of hearing
• IX & X- uvula deviates to one side, no gag, hoarse or brassy voice, dysphagia
• XI- absent movement of sternomastoid or trapezius muscles
• XII- tongue deviates to one side, slow rate of movement

Motor System

• Includes the brain and spinal cord motor pathways
• Check all major muscle groups:
• Distal
• Proximal
• Check muscle tone, strength, and symmetry
• Note unusual movements and movements such as fasciculations or tics

Gait and Posture

• Walking or ambulating requires coordination of multiple voluntary and involuntary functions
• Check strength, coordination, symmetry, balance, stance, speed, stride length, and arm and foot movement

Cerebellum

• Cerebellum responsible for voluntary movement and motor coordination
• Tests for balance include: Romberg test pronator drift, eyes closed, tandem or one foot, knee bends and walking on heels and toes.
• Tests for coordination are rapid pronation/supination on thighs, alternately touch nose with fingers, touch each finger to thumb.

Sensory System

• Routinely assess hands, lower arms, abdomen, lower legs, and feet to test sensation
• Flex muscles, resisting against opposite force
• Light touch with cotton tipped swab
• Vibration using tuning fork on bony prominence
• Kinesthetic sensation (proprioception) by moving finger/toe up/down

Reflexes

• Babinski is a reflex also known as the plantar reflex
• Stroke the bottom of foot from heel to toe
• Note big toe movement
• Expected finding - Plantar flexion (toes curl)
• Unexpected finding toes fan upward, indicates CNS dysfunction

Deep Tendon Reflexes

• Deep tendon reflexes are an involuntary action in response to impulse sent to CNS, this can be an early indication of any dysfuction
• Check DTRs: biceps, patellar, Achilles
• Reflexes are rated as:
• 0
• 1+
• 2+
• 3+
• 4+

Meningeal Signs

• Neck Mobility
• Brudzinski's sign
• Kernig's sign

Diagnostic Evaluation

• CT Scan
• Positron Emission Tomography
• Magnetic Resonance Imaging
• Lumbar Puncture
• Cerebral Angiography
• Myelography
• Noninvasive Carotid Flow Studies
• Transcranial Doppler
• EEG
• EMG & Nerve Conduction Studies

Sample Documentation

• Mental Status: alert, relaxed, and cooperative. Thought processes coherent. Client oriented to person, place, and time
• Cranial Nerves: I-deferred, CN II-XII- intact
• Motor: Good muscle bulk and tone. Strength 5/5 throughout
• Cerebellar: rapid alternating movements (RAMs), finger to nose (F to N), heel to shin (H to S), intact. Gait steady with normal base. Romberg- maintains balance with eyes closed. No pronator drift
• Sensory: light touch, position, and vibration intact
• Reflexes: 2+ and symmetric

Considerations

• Pediatric timing and mastery of developmental milestones can reveal much information and loss of abilities can also be a red flag. Failure of reflexes to diminish, or disappear, can also be considered a red flag.
• In geriatric patients, consider diminished taste and smell, reduced muscle bulk, intentional movements, and longer memory recall times. There will be some memory loss, but sensory processing may diminish with aging. Assess the balance and gait frequently in order to prevent any falls

Health Promotion for CVA

• This is a cerebrovascular accident
• Consider older adulthood, but risk doubles each decade after 55
• Male sex (slightly higher risk)
• AA
• HTN
• Smoking
• Chronic ETOH intake (>2 drinks/day)
• Hx of CV disease
• Sleep apnea
• DM
• Drug abuse
• High estrogen levels
• Overweight
• Sedentary lifestyle
• Family hx of CVA

Terminology

• Clonus- involuntary, rhythmic muscle contractions
• Agnosia- Inability to recognize by sight, touch or hearing.
• Akinesia- complete or partial loss of voluntary muscle movement
• Apraxia- inability to carry out learned sequential movements or commands
• Dysarthria- defective speech
• Dysphasia- difficult speech
• Dysphonia- difficulty with voice; hoarseness
• Proprioception- awareness of posture, movement.
• Aphasia- absence or impairment of ability to communicate through speech and writing.
• Expressive- inability to express language
• Receptive- inability to comprehend written language.

Patient who is unconscious patient

• Assess CN responses where applicable
• (pupillary response) assess responses to any stimulus responses and last resort use painful stimuli assess risk for DVT.
• Describing levels of consciousness Adjectives (lethargy, obtunded, stuporous, and comatose