uses cartoon faces that express the spectrum of comfort to severe pain. (Other more complex pain scales and assessment tools available for use in patients with cognitive impairment can be found in Chapter 28).
The neurologic examination
A neurologic examination is a mosaic of focal examinations of the nervous system. Major subsystems include motor function, sensation, reflexes, gait, coordination, brainstem functions, language, and mental status. Additional components of the examination may be added as needed.
(SeeThe Mayo Clinic Examinations in Neurology, or Essentials of Clinical Neuroanatomy and Neurophysiology).
The motor examination The motor system is responsible for producing, organizing and control- ling movement. The motor examination evaluates the patient’s muscle bulk, tone and strength.
Evaluation of motor control is included in the coordination examination. The patient is asked to perform specific tasks that gauge the strength and function of individual muscles and muscle groups. For example, the examiner may ask the patient to resist extension at the elbow to evaluate the strength of the biceps muscle. Observing or palpating the size of the muscles evaluates muscle bulk. Mild generalized reduction in muscle bulk is common in the normal aging of the elderly patient. Asymmetry or focal loss of muscle mass is abnormal and often indicates chronic damage to the nerves innervating that muscle or group. Muscle tone is the resting level of muscle activation.
Even in a relaxed state some of the muscle fibers are contracted or tightened. This low level of contraction keeps the muscle ready for use and protects it from being inadvertently overstretched.
Passively moving the patient’s relaxed limb and assessing the resistance to the passive movements best examine tone. Muscle tone is reduced in certain situations including injury to the peripheral nerve, or certain states of reduced consciousness. In contrast, increased tone is common after injury
Figure 6.1 The tools of the neurologic examination. These often include a pin, tuning fork, reflex hammer, ophthalmoscope and otoscope, tongue depressor, and vision card.
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to the central nervous system such as spasticity after a stroke.Spasticityis an involuntary tightness of the muscle or limb that worsens with faster movements. Other central nervous system disorders such as Parkinson’s disease result in a specific increase in tone, termedrigidity. In these patients, the rigidity manifests as stiffness present throughout the range of motion and independent of the velocity of the movement. Some patients with cognitive impairment, anxiety, or nervous tension may have difficulty fully relaxing their muscles and consequently display paratonia. In paratonia, there is incomplete or inconsistent relaxation, sometimes resulting in jerky passive limb movements. Further discussion can be found in chapter 18.
The sensory examination The sensory system detects and transmits information about the outside world. It begins with the nerve endings in the skin and internal organs. This includes peripheral sensory nerves that connect through the spinal cord to sensory centers in the brain. The primary sensory modalities include temperature, light touch, vibration, pain, pressure, and position. Loss of any of these sensory modalities alone or in combination indicates a break in the anatomical chain of communication. The patient may be unable to detect the sensation, or may report a feeling in the absence of a stimulus, akin to a sensory hallucination.
The sensory examination presents stimuli to the patient and gauges the response. Vibration is tested by applying the base of a vibrating tuning fork (128 Hz) on the patient’s toe or finger. The flat surface of the tuning fork can be applied to screen temperature sensation. Proprioception, or joint position sense, is tested by asking the patient to report if the examiner has moved the patient’s great toe up or down. Some patients with cerebral lesions can detect stimuli but not make higher discriminations. Patients withastereognosiscannot identify by feel alone, the identity of a familiar handheld item, such as a pen. They may describe the pen’s shape or texture but can- not identify the object until they open their eyes. Cortical sensory deficits can also impair two- point discrimination—the ability to discern two distinct points pressed on the patient’s skin—
andgraphesthesia—identifying numbers traced on the hand. This includes extinction to double simultaneous tactile stimulation, most often found in patients with left hemineglect due to right hemisphere (often parietal) lesions.
Normal aging affects the sensory system. Healthy elderly individuals may demonstrate mild reductions in vibratory sensation in the toes. Changes in skin thickness and texture, or edema of the limb, can reduce temperature or light touch perception. There can be changes in pain threshold and pain tolerance.8The sensory examination requires an attentive patient and good communication. Patients with language or cognitive impairments may not understand test instructions or communicate subtle differences in sensation.
Examination of reflexes Tendon stretch reflexes are elicited by percussion of a muscle or tendon, as with tapping the patellar tendon at the knee with a reflex hammer to elicit contraction of the quadriceps. Reflexes are also commonly checked at the biceps, triceps, brachioradialis in the arm and Achilles tendon at the ankle. These maneuvers test the integrity of the neurologic circuit from the tendon to the spinal cord and back to the limb. Asymmetric reflexes identify a lesion or injury. If the reflex is reduced, or absent, the problem lies in the peripheral nervous system or muscle. If the reflex is excessive or“brisk,”the problem is in the CNS.
Reflex amplitude may decline with age-related reduction in muscle bulk. Relaxation of the limb is essential for proper examination, which can be difficult in patients with cognitive impairment or nervousness. Sometimes the examiner can distract the patient or ask to perform a simple task with another limb.
Pathologic reflexes Some cutaneous reflexes provide signs of CNS disease, as with the famous Babinski sign, which is tested by stroking the sole of the foot. If present, the toes extend upward and fan outward, indicating damage to central motor pathways serving that leg. In healthy patients, the toes would curl down in flexion. Other pathologic reflexes are“released”when neural mechan- isms that suppress them are damaged. For instance, the rooting reflex or suck reflex present in
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infants may reemerge in stroke or neurodegenerative disease. The patient may involuntarily suck on a tongue blade or root with the lips in response to stroking the outside of the mouth, like a sucking infant. With Myerson’s sign, a patient is unable to suppress blinking when tapped on the glabella (located between the bridge of the nose and the brows); it may be seen in Parkinson’s disease and other neurodegenerative conditions.
The coordination examination Examination of coordination relies on observing the patient making simple repetitive and complex movements. At first, the examiner watches the patient for seemingly involuntary or inefficient movements such as a twitch or tremor. The examiner asks the patient to touch his or her nose with eyes closed, and then with eyes open. Then, the examiner asks the patient to alternate touching the nose and the examiner’s finger— stationary and moving. Ataxia manifests as a clumsiness or inexactness of movements.
A common cause of temporary ataxia is alcohol intoxication. Individuals with ataxia have diffi- culty walking in a straight line, maintaining balance, or performing precise motor movements.
This includes the motor movements of speech and consequently results in a slurred or mumbled speech pattern. The coordination exam includes notation of the speed and regularity of rapid alternating simple movements such as toe-tapping and rapid opposition of the thumb and index finger. When there is incoordination, the rate of the repeated movements becomes slower and irregular.
Ataxia implies injury to the cerebellum, brainstem, or proprioceptive peripheral nerves.
Coordination may diminish in the normal elderly individual due to changes in somatosensory, vestibular, and visual functions. Fine motor control or smoothness of limb movement can be reduced by loss in joint range of motion or arthritis. Pain in the limb or joint may also result in a slowness or inexactness of motion. Impaired vision from cataracts, reduced acuity, or macular degeneration will impair the patient’s ability to find the target for some testing.
The gait examination Normal gait depends on balance, coordination, strength, tone, and accurate sensory input from the limbs. Gait is also affected by balance input from the inner ear and vestibular systems. Vision acts as confirmatory feedback alerting the brain to any obstacles or impending changes at the ground level. The visually impaired patient may have severely impaired gait if any of the other subsystems are diminished. Examples of abnormal gaits include the ataxic gait, spastic gait, or Parkinsonian gait. A patient with ataxia or incoordination may walk with wide legs and arms out as if to touch a wall. In disorders of increased tone, such as rigidity due to Parkinson’s disease, the gait may be slow and unsteady, with stiff leg movements and small steps.
When spasticity is present following a stroke or other corticospinal lesion, the patient may circumduct (swing around) the stiff extended spastic leg rather than extending it directly forward.
Patients with gait apraxia have the necessary components to produce gait and locomotion, but can’t generate normal gait. They have difficulty lifting their feet off the ground or initiating gait.
They may complain of“imbalance”or“weakness.”Apraxia of gait is a condition often associated with NPH, which includes dementia and incontinence.
Examination of gait consists primarily of observation of the patient’s relaxed walk. Normal gait necessitates a rapid and smooth shifting of body weight between the legs. In doing so, the legs and feet seem to gracefully swing forward taking even turns. Observe that the toes are elevated just enough to glide over the ground, and the heels narrowly escape striking each other as they pass during the stride. The upper body maintains the center of gravity, and the arms alternately swing to counterbalance the legs. It has been said that gait is a physiologic wonder and the most complex noncognitive function of the nervous system. Consequently, to the keen observer, examination of a person’s gait can be one of the most sensitive indicators of neurologic dysfunction.
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Examination of the cranial nerves and brainstem The brainstem includes the medulla oblongata, pons, and midbrain and is essential for basic vegetative functions of life. These structures also are the primary control for eye movements, facial motor and sensory function, swallowing, and the special senses including hearing and taste. Examination of the brainstem is an important component of the neurologic examination, and key to the evaluation of altered mental state including stupor and coma. Examination of the brainstem should encompass all of the 12 paired cranial nerves exiting the brainstem. The nerves are numbered from the top down such that the 12th cranial nerves exit the brainstem at the lowest portion of the medulla (Figure 6.2 and Table 6.4).
Smell and taste The olfactory nerve is part of the CNS and mediates the sense of smell and, indirectly, taste. It is often omitted from routine examinations, and can be tested by having the patient detect or identify common and distinct scents of aromatic substances (using small vials of camphor, coffee grounds, perfume, or other aromatics) or proprietary“scratch and sniff”cards impregnated with common scents. Olfactory nerve lesions reduce or eliminate sense of smell (hyposmia and anosmia). Hyposmia has been associated with chronic conditions including Parkinson’s disease,9Alzheimer’s disease and MCI,10and head trauma due to injury of olfactory nerve twigs passing through the cribriform plate or damage to their source in olfactory cortex.11 Olfactory dysfunction can also be caused by chronic meningitis, smoking, sinus disease, and viral infections. Olfactory dysfunction has potential effects on diet, appetite, and enjoyment of pleasurable scents. Some patients may overseason their food. Safety implications may include reduced ability to distinguish spoiled food or gas leaks.
Taste depends on glossopharyngeal and trigeminal nerves (and to a small extent, the facial nerve). These nerves are routinely tested except for their role in taste. Taste can be tested by apply- ing substances to the tongue representing primary taste components–sweet, salty, bitter, sour, or umami. Abnormal sense of taste, dysgeusia, can follow dry mouth, smoking, and medication side effects. Dysgeusia may manifest as aversion to food in sick people and is not uncommon among the elderly. Despite no direct connection between the olfactory nerves and mouth, the olfactory nerve contributes to taste, and anosmia often affects taste.
Vision The second cranial nerve, the optic nerve, is also part of the CNS. After the optic nerve enters the eye, its fibers spread out across the retina. Ophthalmoscopy of the optic nerve head and retina provides a direct window to the CNS. Pupillary responses to light are tested in each eye.
Visual acuity is checked using a standard eye chart such as a Snellen eye chart or Contrast Sensitivity Chart. Color is screened by asking the patient to identify the hue of an object presented in the center or periphery of their visual field. Visual field defects are screened by asking the patient to identify moving fingers or report the number of fingers presented in each of the four quadrants of each eye separately (with the other eye closed). Reduction in visual acuity is very common in the aging population, along with other age-related eye diseases such as cataracts or macular degeneration. Neurodegenerative diseases and strokes also produce visual impairment through damage to the visual cortex and related subcortical structures. Specialized tests and techniques, such as optical coherence tomography (OCT), examine the retina in greater detail and may provide evidence of neurodegenerative disease.
Eye movements The third (oculomotor), fourth (trochlear) and sixth (abducens) cranial nerves belong to the peripheral nervous system and control movement of the eyes via the extraocular muscles within the orbits. These nerves work together with other brainstem control centers to keep the eyes focused and directed on objects of interest. Pupil constriction is controlled by the third cranial nerve. The second and third cranial nerves work together to detect light and constrict the pupil respectively. The normal pupillary response to light is constriction, and when either eye is presented with a light, they both should constrict consensually. This normal pupillary response suggests integrity of the optic nerve from the retina to the brainstem.
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Pons Midbrain
Medulla (A)
(B)
Figure 6.2 The brainstem and cranial nerves. A. Underside view of the brain and brainstem. Note the pairs of cranial nerves exiting the brainstem. (Based on Lynch28) B. Side view of the brain and brainstem with identification of the brainstem components. (Based on OpenStax College29).
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The eyes move conjugately under the direction of the brain and brainstem to allow binocular vision, depth perception and visual search. Aging modestly reduces conjugate upgaze. When the eyes do not move conjugably, diplopia or double vision results. Dysconjugate gaze may follow a brainstem stroke or reflect congenital strabismus. The aging patient may lose the ability compen- sate for slight misalignment of the eyes and report intermittent diplopia. Such subtle weaknesses can be elicited during the eye exam with the“cover-uncover”test. Eye movements are affected prominently in some neurodegenerative disorders. For example, progressive supranuclear palsy severely restricts vertical gaze. Parkinson’s disease can affect eye movement speed and trajectory.
For further details, see chapter 15.
Facial strength and sensation The fifth cranial nerve, or trigeminal nerve, mediates sensory information for the face on the same side and comprises three branches suppling the lower face and jaw (V3), cheek (V2) and forehead and cornea (V1). The examination is similar to that described for the earlier section on the Sensory Examination. Trigeminal neuralgia produces severe shooting unilateral pain often provoked by stimulation of the face (tooth brushing, chewing, touching). Herpes zoster reactivation, or“shingles,” manifests as a blistering rash with severe unilateral facial pain.
The facial, or seventh, cranial nerve moves the face. The examiner observes the patient’s face at rest and in action. The patient should be asked to make different facial expressions, close the eyes, and raise the eyebrows. Subtle facial weakness may be apparent with natural expressions such as laughing at a joke. Facial weakness or reductions in tone can be confused with sagging or lax facial skin. A facial nerve lesion impairs movement of the upper and lower face on the same side, as in Bell’s palsy. There may be trouble closing the eyelid, or with food leaking from the corner of the mouth. The facial nerve also innervates the tensor tympani and stapedius muscles—which protect the ear from noise by reducing the vibration of the small bones of the inner ear—and may account for auditory complaints with Bell’s palsy. After the facial nerve heals and re-innervates the facial muscles, the patient can experience spasms or twitches of the face. Facial weakness from cerebral hemisphere damage, such as a stroke, affects the lower face opposite the lesion, sparing the forehead. Parkinson’s disease produces a characteristic“masked”face with a paucity of expression and reduced blink frequency.
The facial nerve mediates taste from the anterior two-thirds of the tongue via the chorda tympani, in conjunction with trigeminal nerve fibers. The corneal reflex involves both nerves.
The examiner touches the edge of the cornea with a wisp of cotton. This stimulates the trigeminal nerve, which in turn activates the facial nerve, causing a blink. Lack of blink implies a lesion of either nerve or the brainstem.
Table 6.4 Cranial nerves and their functions.
Cranial Nerve Function
I (Olfactory Nerve) Smell
II (Optic Nerve) Vision
III (Oculomoter Nerve) Major control of eye movements, pupil constriction IV (Trochlear Nerve) Rotation and depression of the eye
V (Trigeminal Nerve) Facial sensation
VI (Abducens Nerve) Outward deviation of the eye VII (Facial Nerve) Motor control of the face
VIII (Vestibular Nerve) Hearing and detection of momentum IX (Glossopharyngeal Nerve) Taste and sensation of the back of the mouth
X (Vagus Nerve) Motor control of the back of the mouth, throat, and voice box.
XI (Accessory Nerve) Shoulder shrug and neck turning XII (Hypoglossal nerve) Motor control of the tongue
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Hearing and balance The eighth cranial nerves connect from the auditory and vestibular sensors of the inner ears to the brainstem. Hearing loss, or presbycusis, is one of the most common age-related ailments and may be downplayed or unrecognized by the patient. With loss of hearing comes a form of isolation from friends, family, and sources of enjoyment, such as music. This increases the risk of depression, which can compound the isolation. When impaired balance leads to stumbles or falls, the patient may be embarrassed and less inclined to socialize. Injuries from falls to the ground, such as pelvis or femur fractures and head trauma with brain injuries and bleeding (e.g., subdural hematomas), are a leading source of morbidity and mortality in the aging population.
The patient should have their hearing aids during the history and examination. Note if the patient usually wears hearing aids and if they are functioning. To screen for hearing problems, the examiner asks the patient to identify a sound, such as the examiner’s fingers rubbing together, as in the calibrated finger rub auditory screening test.12A tuning fork (512 Hz) may also be used to test hearing or differentiate between conductive and sensorineural hearing loss, such as in the Weber and Rinne tests. Conductive hearing loss occurs when sound cannot pass through the inner ear due to earwax, a punctured eardrum, or fluid in the middle ear. Sensorineural hearing loss occurs when auditory nerves or hair cells are damaged or degenerate as in aging.
The eighth cranial nerve vestibular balance function is indirectly assessed during the coordina- tion, gait, and eye movement portions of the exam. Vestibular dysfunction may cause nystagmus or irregular jerking of the eyes. Patients may complain of“dizziness”with changes in position or head movements. They may have an unsteady gait or difficulty standing in one place. In Romberg’s test, the patient is asked to stand with his or her feet together and arms outstretched and with eyes closed. Removing visual cues for postural stabilization relies on the vestibular system and inputs from proprioception in the lower extremities to maintain balance. An abnormal response is inability to maintain this position without widening stance, or stumbling. The examiner can examine the vestibular nerve with the head-impulse-test (HIT) and VOR suppression test to evaluate the vestibulo-ocular reflex (VOR), which helps keep the eyes fixed on a target even when the head is moving. Normally during the head-impulse-test the patient should be able to keep their eyes fixed on an external target, such as the examiner’s nose, despite gentle passive rotation jerks of the patient’s head by the examiner. An abnormal response, such as a corrective targeting eye movement after the rotation has ceased, indicates an abnormal VOR and thus abnormal communication between the inner ear and brainstem. The VOR suppression test assesses ability to suppress vestibular input. The patient must maintain gaze on his or her own outheld hand while being rotated as on a swivel chair. The affected individual cannot maintain gaze on target and may show nystagmus with attempted refixation (see also chapter 16).
The lower cranial nerves The ninth (glossopharyngeal), tenth (vagus) and twelfth (hypoglossal) cranial nerves serve tongue, palate, and pharyngeal movements, and are often examined together.
The patient is asked to open the mouth and say,“aah.”The palate may sag on the lesion side, with the uvula deviating toward the normal side. When there has been an injury to the hypoglossal nerve the tongue will deviate toward the weaker side when protruded. If the hypoglossal injury is chronic, there may be tongue atrophy on the side of the lesion. The eleventh cranial nerve, the accessory nerve, comprises fibers from the lower medulla and uppermost cervical spinal cord and supplies the trapezius and sternocleidomastoid muscles in the neck. The nerve is examined by asking the patient to shrug the shoulders or turn their head to either side against resistance. Hoarseness (dysphonia) and trouble swallowing (dysphagia) are not uncommon in aging and may be severe with degenerative diseases affecting cranial nerves or nuclei and supranuclear control, as in amyotrophic lateral sclerosis (ALS) and Parkinson’s disease.
Examination of language Language is human communication, spoken or written, using words and gestures in an organized and conventional way. It differs from the act of speech, which is a more basic motor and coordination function. The language examination evaluates the content, 115 Medical Assessment of the Aging Mind and Brain