Assessment of Neurologic System

1. Assessment of Neurologic System

2. Anatomy and Physiology • Nervous system controls body functions through voluntary and autonomic responses to external and internal stimuli • Nervous system consists of the central nervous system (brain and spinal cord), peripheral nervous system and the autonomic nervous system

3. Anatomy and Physiology: Central Nervous System • Protective structures • Skull protects the brain • Foramen magnum – spinal cord extends from medulla oblongata in brainstem • Meninges – between the skull and the brain • Dura mater, arachnoid and pia mater • Subarachnoid, between arachnoid and pia mater, where cerebrospinal fluid (CSF) circulates

6. Cerebral ventricular system – four interconnecting chambers (ventricles) that produce and circulate CSF • One lateral in each hemisphere, 3rd adjacent to thalamus, 4th adjacent to brainstem.

8. Cerebrospinal fluid and cerebral ventricular system • CSF –colorless, odorless fluid that contains glucose, electrolytes, oxygen, water, carbon dioxide, protein and leukocytes • Produced in choroid plexus of ventricles • Circulates around brain and spinal cord to provide cushion, maintain normal intracranial pressure, provide nutrition and remove metabolic wastes • CSF circulation: from lateral ventricle through interventricular foramen to 3rd ventricle through aqueduct of Sylvius to 4th ventricle into cisterna magna (small reservoir for CSF). • From cisterna magna, CSF flows up around brain and down around spinal cord. • CSF absorbed through arachnoid villi and returned to venous system

12. Anatomy and Physiology: Brain • Consists of cerebrum, diencephalon, cerebellum and brainstem • Gray matter (cell bodies) and white matter (myelinated nerve fibers)

13. Anatomy and Physiology: Brain (cont) • Cerebrum – Largest part of brain • Composed of two hemispheres divided into four lobes ( frontal lobe, parietal lobe, temporal lobe, and occipital lobe) • Frontal lobe –primary motor cortex and responsible for voluntary motor activity functions, controls intellectual function, awareness of self, personality and autonomic responses related to emotion • Left frontal lobe – Broca’s area – formulation of words • Parietal lobe – contains primary somesthetic (sensory) cortex • Major function to receive sensory input such as position sense, touch, shape and texture of objects • Temporal lobe –contains primary auditory cortex and interprets auditory, visual and somatic sensory inputs that are stored in thought and memory • Left temporal lobe – Wernicke’s area – responsible for comprehension of spoken and written language • Occipital lobe – contains primary visual cortex and is responsible for receiving and interpreting visual information

20. Anatomy and Physiology: Brain (cont) • Diencephalon – comprises thalamus, hypothalamus, epithalamus and subthalamus • Thalamus – relay station • Hypothalamus – maintain homeostasis • Regulation of body temperature, hunger and thirst, formation of autonomic nervous system responses and storage and secretion of pituitary gland hormones • Basal ganglia - create smooth, coordinated voluntary movement by balancing production of two neurotransmitters: acetylcholine and dopamine

23. Anatomy and Physiology: Brain (cont) • Brainstem – midbrain, pons and medulla oblongata • Midbrain – relay stimuli concerning muscle movement to other brain structures, • Pons – relays impulses to brain centers Medulla oblongata – reflex centers for controlling involuntary functions of breathing, sneezing, swallowing, coughing, vomiting and vasoconstriction.

24. Cerebellum – separated from cerebral cortex by tentorium cerebelli • Coordinate movement, equilibrium, muscle tone and proprioception. Controls movement for same side of body (ipsilateral)

26. Anatomy and Physiology: Brain (cont) • Blood flow • Carotid arteries supply 80% to brain and two vertebral arteries supply 20% • Blood to cerebrum by posterior, middle and anterior cerebral arteries • Posterior and anterior communicating arteries to circle of Willis • Blood leaves brain through venous sinuses into jugular veins

32. Anatomy and Physiology: Spinal Cord • Spinal cord – continuation of medulla oblongata • Begins at foramen magnum and ends at L1/2 vertebrae • At L1/2 branches into lumbar and sacral nerve roots ( cauda equina) • Nerve fibers transmit sensory, motor and autonomic impulses between brain and body • Descending (motor) tracts carry impulses from frontal lobe to muscles for voluntary movement and play role in muscle tone and posture • Ascending (sensory) tracts carry sensory information from body through thalamus to parietal lobe

36. Anatomy and Physiology: Peripheral Nervous System • Cranial Nerves • 12 pairs: 5 pairs (motor fibers only), 3 pairs (sensory fibers only) and 4 pairs (motor and sensory fibers) • Spinal Nerves • 31 pairs: 8 pairs cervical, 12 pairs thoracic, 5 pairs lumbar, 5 pairs sacral and 1 pair coccygeal • First seven cervical nerves exit above corresponding vertebrae • Rest exit below corresponding vertebrae • Motor fibers carry impulses from brain (frontal lobe) through spinal cord to muscles and glands • Sensory fibers carry impulses from sensory receptors of body through spinal cord to brain (parietal lobe)

37. Anatomy and Physiology: Peripheral Nervous System (cont) • Reflex Arc • Response to sensory stimuli • Deep tendon reflexes – responses to stimulation of a tendon that stretches neuromuscular spindles of a muscle group • Strike a deep tendon reflex – stimulates sensory neuron that travels to spinal cord – stimulates interneuron – stimulates motor neuron to create movement • Superficial reflexes tested in same manner • Each reflex corresponds to specific spinal segment

39. Anatomy and Physiology: Autonomic Nervous System • Regulates body’s internal environment with endocrine system • Sympathetic nervous system • Activated during stress (flight or fight response) • Increase blood pressure and heart rate, vasoconstricting peripheral blood vessels, inhibits gastrointestinal peristalsis and dilates bronchi • Parasympathetic nervous system • Controls vegetative functions (breed and feed) • Conserving energy: decrease heart rate and force of myocardial contraction, decrease blood pressure and respiration and stimulate gastrointestinal peristalsis

40. Dilation of ventricles Cortical atrophy (greater in frontal and temporal lobes) Decrease in brain weight (decrease in neuron size) Change in release of neurotransmitter Changes in motor function – stooped, forward-flexed posture and slow gait Loss of muscle strength Changes in sensory and motor function, memory, cognition and proprioception Decline in sensorimotor function Changes in eye-lens thicken, smaller pupil size Hearing loss (50% over 75) Decrease in short term memory Decline in fluid intelligence Slow reaction time Anatomy and Physiology: Gerontological Considerations

41. Health History: Present Health Status • Changes in ability to move around or participate in usual activities • Any chronic diseases – Hypertension, Myasthenia gravis, Multiple sclerosis • Chronic disease prevent maintaining healthy lifestyle • Medications – anticonvulsant, antitremor, antivertigo or pain medications • Alcohol consumption, legal or recreational mood-altering drugs

42. Health History: Past History • Injury to head or spinal cord. Residual changes from experience • Surgery to brain, spinal cord or any nerves. Outcome of surgery • Stroke. Residual changes • Seizure disorder, type, frequency, prevention

43. Health History: Family History • Stroke, seizures or tumor of brain or spinal cord

45. Risk Factors for Brain Attack • Non-modifiable • Age • Gender • Family history • Race • Previous brain attack or heart attack • Modifiable • Smoking • Control of Diabetes • Coronary artery disease • Transient ischemia attacks • Atrial fibrillation • High serum cholesterol • Obesity • Excessive alcohol intake • Cocaine use

46. Problem-Based History • Using symptom analysis or “OLD CARTS” for each of the following symptoms • Headache, recent surgeries or medical procedures (spinal anesthesia or lumbar puncture) • Dizziness or light headedness, difficulty keeping balance, feel like may fall, associated with positional change or activity, sensation of room spinning • Seizures, become unconscious, warning signs of impending seizure, if unconscious – progress through body, change in color of face or lips, loss of bowel or bladder control, length of time before back to normal self, feelings afterwards, confused, headache or aching muscles, sleep, factors that start seizure (stress, fatigue, activity or stopping medication), methods initiated to prevent injury during seizure, affect on your lifestyle, wear alert ID, occupation

47. Problem-Based History (cont) • Loss of Consciousness, blackout or faint –occurs suddenly, history of diabetes, liver failure or kidney failure • Changes in movement – length of time had mobility change, continuous or intermittent, tremors or shaking of hands or face, affect of tremors or shaking on performance of ADL’s, history of thyroid disease, twitches or sudden jerks, sense of weakness in or difficulty moving parts of body, associated with an activity, problems with coordination or keeping balance, lean to one side, legs give way • Change in sensation – numbness or tingling, description of feeling, associated with any activity • Dysphagia –length of time, involve liquids or solids or both, excessive saliva or drooling, cough or choke when trying to swallow • Dysphasia/Aphasia – length of time, difficulty forming your words or finding right words, understanding things said to you, change in handwriting

48. Physical Examination • Many of the cranial nerves will be examined later under the specific system, eg eyes etc. For this reason, we will omit them here but they are considered indicative of Neurological assessment.

49. Aromatic material Penlight Tuning Fork Cotton-tipped applicator Tongue blade Disposable gloves Paper clip Cotton ball Percussion hammer Snellen’s chart Examination: Equipment

50. Glascow Coma Scale • Best eye opening response Spontaneously 4 To verbal command 3 To pain 2 No response 1