Deep Tendon Reflexes
Deep tendon reflexes (DTRs) are a fundamental part of neurological assessments conducted by nurses and other healthcare professionals. They provide critical information about the integrity of the nervous system, specifically the peripheral nerves and spinal cord.
During the assessment, a rubber hammer is typically used to tap briskly on a tendon, such as the patellar tendon located just below the knee. The normal response is an involuntary contraction of the muscle connected to the tendon being tapped, like the kick observed when the patellar tendon is struck.
The presence, absence, or abnormality of these reflexes can indicate neurological conditions. For instance, hyperreflexia, an exaggerated response, may suggest a neurological disease such as a upper motor neuron lesion, while hyporeflexia, a diminished or absent response, might indicate a lower motor neuron issue.
Grading Reflexes
Reflexes are usually graded on a scale from 0 to 4. A grade of 0 indicates no reflex, 1 suggests a diminished reflex, 2 is considered normal, 3 is brisker than normal, and 4 indicates hyperreflexia, which often involves repetitive reflex motion. This grading allows nurses to quantify reflex responses and track changes over time.
Cranial Nerves
Cranial nerves are a set of twelve nerves that originate directly from the brain and control a variety of functions, ranging from sensory perception to motor control and autonomic functions.
A thorough neurological assessment includes a check of all these nerves. Nurses assess them by performing specific tests to evaluate functions such as smell (I), vision (II), eye movements (III, IV, VI), facial sensation and muscles (V, VII), hearing and balance (VIII), swallowing (IX, X), shoulder and neck muscle movement (XI), and tongue movement (XII).
Common Tests
For example, to assess the optic nerve (II), a nurse would examine visual acuity and visual fields, while assessing the facial nerve (VII) includes asking the patient to frown, close their eyes tightly, smile, and puff out their cheeks.
Any abnormalities found in these tests can give important clues about the presence and localization of neurological disorders, such as a stroke or cranial nerve palsies.
Sensory Perception
Sensory perception refers to the ability to perceive stimuli through our sensory organs and includes touch, pain, temperature, position sense, and vibration. Neurological assessments meticulously evaluate these modalities to determine if the sensory pathways of both the peripheral and central nervous system are functioning correctly.
A nurse will usually perform a sensory exam using various instruments, such as a monofilament for touch, tuning forks for vibration, and hot and cold objects for temperature testing.
Pain and Light Touch
Pain sensation can be tested with a sharp object, while light touch might be tested with cotton wisp or simply the examiner's fingers. Position sense, or proprioception, involves the patient's ability to perceive the location and movement of body parts without visual input, and is often assessed by moving the patient's finger or toe up and down and asking them to identify the direction of movement.
This sensory screening is vital for localizing neurological lesions and understanding the nature of a patient's complaint, such as numbness or tingling.
Coordination
Coordination is the ability to perform smooth, accurate, and controlled body movements, and is an important parameter tested during neurological assessments. Coordination tests typically focus on cerebellar function, as the cerebellum is crucial for maintaining posture, balance, and coordinating voluntary movements.
A classic coordination test is the finger-to-nose test, where a patient is asked to touch their nose with their fingertip and then touch the examiner's finger, which is moving in different positions. Similarly, the heel-to-shin test is another common coordination test.
Rapid Alternating Movements
To assess rapid alternating movements, a patient may be asked to quickly flip their hands back and forth on their thighs or perform rapid alternating finger-to-thumb touches.
Impairment in coordination, known as ataxia, could signify a potential problem in the cerebellum or other parts of the nervous system. Precise documentation of coordination abilities can help in diagnosing conditions such as stroke, multiple sclerosis, or even hereditary ataxias.
