Neuro Foundations 3 Lecture Notes PDF

OCCTH 583 NEURO FOUNDATIONS 3 Jennifer Krysa, MSc, Reg OT (AB), OTR The Neurologic Examination Mental Status Cranial Nerves Motor System Muscle Strength Gait, Stance & Coordination Sensation Reflexes Autonomic Nervous System 2 Mental Status 1. Level...

OCCTH 583 NEURO FOUNDATIONS 3 Jennifer Krysa, MSc, Reg OT (AB), OTR The Neurologic Examination Mental Status Cranial Nerves Motor System Muscle Strength Gait, Stance & Coordination Sensation Reflexes Autonomic Nervous System 2 Mental Status 1. Level of Consciousness Alert: actively perceiving surrounding world Comatose: not responding to any stimuli Intermediate levels: descriptive words often used (stuporous, lethargic, drowsy) but lacks precision Add details like rousable, repeat instructions needed, the stimulus used to awaken, how long they stay awake, … 2. Content of Consciousness Client needs to be both awake and alert to assess If client is inattentive, then this portion is limited 3 Mental Status Examination Occurs as part of a complete Neurological Exam or can be a stand- alone exam Not equivalent to a Psychiatric Interview nor Neuropsychological Testing nor an OT Functional Cognitive Assessment Purpose: diagnosis of neuropathology Strengths: short, practical, flexible Weaknesses: not standardized; often no norms 4 Content of Consciousness Orientation Attention & concentration Memory Verbal & mathematical abilities Judgment Reasoning 5 Orientation 3 common parameters: person, time, place A general assessment of awareness attention and memory Considerations: Place – was the individual ever told where they are, could have been transported unconscious Checking to see if they pick up on environmental cues: hospital, calendar, clock, watch Time – we track time differently in different contexts 6 Orientation to Time – Try It Discuss with a partner how you track or perceive the passage of time E.g date vs day of the week What do you think moving a 3 o’clock meeting back 2 hours means? Do you know when the seasons officially change Big Ben clock face, Elizabeth Tower Attention & Concentration Need attention for memory and perception Spell a 5-letter word forwards & backwards Serial 7s Digit span (forward or backward) 8 Memory Long term: personal history, retrieval of historical information Short term: registration & recall or delayed recall (3-5 objects) 9 Verbal & Mathematical Abilities Language written Reading Spontaneous writing or copying sentence Language spoken repeating sentences object naming/word finding list generation Maths: calculations with simple operations, making change Recognizing digits 10 Judgment “What if” scenarios E.g. … find an addressed stamped envelope on the sidewalk 11 Judgment – Try It In partners see if you can think of any judgment questions to ask, e.g. Everyday scenarios that might happen Needed reactions to minor emergencies Coming to the assistance of others 12 Reasoning Concrete Abstract: similarities between object proverb interpretations 13 Cranial Nerves Travel thru distinct locations in the brain yielding information about brain injury and recovery Videos on KenHub https://www.kenhub.com/en/library/a natomy/the-12-cranial-nerves 14 Related Terminology & Abbreviations Ptosis = drooping of upper eyelid Myadriasis = a larger or blown pupil Diploplia = double vision EOM = extra-ocular movements MOI = mechanism of injury ICP = intracranial pressure 15 1. Olfactory Sensory Usually evaluated only after head trauma (to ethmoid bone) Anosmia=loss of sense of smell Pro tip: use a K-cup [Aside: Most (96%) people living with Parkinson’s present with anosmia before any motor signs appear] 16 2. Optic Sensory MOI: Tumor (pituitary), aneurysm (internal carotid), edema, ischemia, inflammation, demyelination (MS), facial trauma Acuity Colour perception Visual fields Fundus & optic disc is an advanced test: fundascopic examination by an MD 17 3. Oculomotor Motor Upper eyelid (levator palpebrae) Eyeball extrinsics (except superior oblique m.) Constricts pupil (pupillary sphincter m.) Accommodates eye (ciliary m.) MOI: trauma, tumor, infection, aneurysm, increased ICP 18 Tips Pupillary light reflex: II afferent & III efferent Commonly test III, IV & VI together because all motor & associated with EOMs 19 4. Trochlear Trochlea = a structure acting like a pulley Motor Superior oblique muscle MOI: trauma, infection, tumor 20 5. Trigeminal V1: Opthalmic - sensory V2: Maxillary - sensory V3: Mandibular – mixed Jaw jerk reflex MOI: facial trauma (dental), tumor, infection (Herpes zoster) 21 Trigeminal Neuralgia Tic douloureux = chronic pain Sudden attacks of stabbing pain on one side of the face Intermittent 22 6. Abducens Motor Lateral rectus m. MOI: trauma Abnormal findings: diplopia with far vision Lateral rectus muscle palsy 23 7. Facial Mixed Sensory: taste ant 2/3 tongue Motor: facial expression mm. & smaller mm. in ear Motor: lacrimal, submandibular & sublingual glands (parasympathetic) MOI: trauma, inflammation, infection Most commonly paralyzed motor c.n. Unilateral: e.g. Bell’s Palsy Bilateral: e.g. Lyme disease, Myasthenia gravis, GBS 24 8. Vestibulocochlear Sensory Vestibular: semicircular canals, utricle & saccule Nystagmus=rhythmic mvmt of the eyes Slow component caused by vestibular input Quick corrective component causing mvmt in the opposite direction Cochlear: hearing Peripheral sensory input from both ears is combined almost instantaneously 🡪 no central cause of unilateral hearing loss MOI: trauma, tumor (acoustic neuroma) 25 9. Glossopharyngeal Mixed Motor: swallow (stylopharyngeus m.), parotid gland (parasympathetic) Sensory: taste 1/3 tongue, external ear cutaneous, visceral sensation middle ear MOI: trauma (large extra-cranial portion so susceptible to GSW, stabbings, fractures) & tumor 26 10. Vagus Mixed MOI: same as IX glossopharyngeal C.n. IX & X usually tested together Clinically relevant in OT practice for relaxation training i.e. diaphragmatic breathing stimulates the nerve (parasympathetic response) 27 Try It – Box Breathing 28 Aside: Jugular Foramen Syndrome Tumor involving c.n. IX, X, & XI Also: trauma/fracture of occipital bone, infections 29 11. Spinal Accessory Motor Sternocleidomastoid & trapezius mm. MOI: trauma (fracture, GSW, stab), tumor Relatively subcutaneous 30 12. Hypoglossal Motor Intrinsic & extrinsic tongue mm. MOI: neck Sx Tongue protrusion: deviates to affected side 31 Motor System Motor weakness can be due to dysfunction in: Corticospinal tract Basal ganglia Spine Peripheral nerves Muscle Examine the individual for the following … 32 … Atrophy: decreased muscle bulk Hypertrophy: caused by one muscle worker harder to compensate for a weaker m. Pseudohypertrophy: m. tissue is replaced by connective tissue or amyloid Fasciculations: fine irregular twitches under the skin Frequently indicate LMN lesions Myotonia: slowing of the relaxation of muscle following sustained contraction 33 Myotonia Lead Pipe Rigidity: uniform rigidity thru ROM, often with clonus. Suggests a basal ganglia disorder Simultaneous co-contraction of agonists & antagonists Clasp-knife Phenomenon: increased initial resistance to PROM followed by relaxation. Suggests UMN lesion. Usually greatest in flexors of UEs & extensors of LEs 34 Muscle Strength MMT Also screening for factitious weakness E.g. testing middle deltoid (shoulder abduction) 35 Gait, Stance & Coordination Gait & stance (incl posture) have their own lectures/labs Coordination we will practice in lab this week Motor weakness in corticospinal pathway Cerebellar dysfunction 36 Sensation We have an entire lab on somatosensory assessment 37 Reflexes Deep Tendon Reflexes (DTRs): muscle stretch LMN lesions depress reflexes UMN lesions increase reflexes More in lab this week Pathologic Reflexes: reversions to primitive responses previously integrated in infancy/early childhood. Loss of cortical inhibition Clonus (UMN lesion) 🡪 more in lab this week Sphincter reflexes: significant in SCI; MDs do, not therapists 38 Pathologic Reflexes Babinski & Hoffmans’ in lab this week Rooting: stroke lateral lip 🡪 turn mouth to stimulus Snout: tap across lips 🡪 pursing of lips Grasp: stroke palm 🡪 finger flexion 39 Autonomic Nervous System Postural hypotension Heart rate changes during Valsalva maneuver Decreased or absent sweating Horner syndrome: unilateral ptosis, pupillary constriction, facial anhidrosis Note any reported changes in: sexual, bowel, bladder & hypothalamic function (temperature, appetite, sleep-wake) 40 Peripheral Nervous System Somatic NS Autonomic NS Sympathetic Parasympathetic Division Division 41 Peripheral Nerves - structure Multiple layers of connective tissue: Endoneurium: surrounds indiv’l n. fibres & houses capillaries Perineurium: binds axons into fascicles Epineurium: fibrous outer layer (sheath) binding fascicles into nerve 42 Peripheral Nerves - types Large Myelinated (fastest) Proprioceptive sensory (m. spindle, vibration, position) Motor Small Myelinated Autonomic Non-proprioceptive sensory (light touch, pain, temp) Unmyelinated Pain, temp sub support Pinprick 43 Peripheral Nerves - Major Four Plexi 1. Cervical Plexus (C1-C4) 2. Brachial Plexus (C5-T1) 3. Lumbar Plexus (L1-L4) 4. Sacral Plexus (S1-S4 plus lumbosacral trunk from L4-L5) 44 Cervical Plexus - nerves Spinal Accessory Greater occipital Facial Cutaneous nn. 45 Brachial Plexus - nerves Axillary Radial Median Musculocutaneous Ulnar 46 Lumbar Plexus - nerves Femoral Obturator 47 Sacral Plexus - nerves Sciatic Common fibular Tibial Superior & Inferior gluteal 48 Peripheral Neuropathies - causes 1. Environmental: heavy metals, chemicals, repetitive motion 2. Diseases: demyelinating (GBS), autoimmune (MS), heredity (Charcot Marie Tooth), diabetes 3. Medication: cytotoxic like chemotherapy 4. Nutritional deficiency: B12, Vit E, B3 (Niacin) 49 Peripheral N. Injury – Seddon Classification Axon intact. Myelin disrupted. Neurapraxia Full recovery days - weeks Intact perineurium & epineurium. Myelin & axon disrupted Axonotmesis Axonal regeneration usually spontaneous Nerve completely severed Neurotmesis Surgery required to restore function 50 Peripheral N. Injury - Sunderland Expanded Seddon’s to 5 classes To better capture degrees of partial injury to nerve fibre Image: Stewart, et al. (2020). Machine intelligence for nerve conduit design and production. Journal of Biological Engineering. 51 Neurapraxia Segmental degeneration (of myelin sheath) Usually from compression Transient conduction block Muscle typically does not atrophy No Wallerian (axonal) degeneration Connective tissues of nerve all intact 52 Axonotmesis Axonal degeneration (Wallerian) Connective tissues (CTs) remain intact MOI: commonly prolonged compression or stretch Spontaneous repair possible (if both proximal & distal ends of CT tube intact) New axons can sprout from damaged axon Recovery: weeks – months Residual deficits possible 53 Neurotmesis Axon & CTs completely severed MOI: trauma, avulsion injury Rapid m. atrophy Sx always required Repair: 1mm/day After 2 years damage is considered irreversible Residual deficits likely A neuroma can form 54 Diabetic Neuropathy Glycemic control dictates severity Usually occurs in distal symmetric pattern Progressive nerve fibre loss & atrophy Sensory & motor Longest nn. most affected Risk factor for skin breakdown Alterations to gait pattern & balance  falls risk 55 Guillain Barre Syndrome (GBS) Immune-mediated syndrome in response to preceding viral infection causes demyelination Sudden onset progressing over hours to weeks Results in characteristic flaccid paralysis & areflexia Weakness & tingling in hands & feet first symptoms Respiratory failure makes it an emergency situation Treated medically with immunoglobulins (IVIg) Most have full recovery Can be slow: weeks to years 56