Neurological Exam: Mental State, Language, Cranial Nerves

Posted on Dec 14, 2024 in Physical Education

Neurological Examination

1. Mental State

  • a) Normal: The patient is alert, provides good answers, and demonstrates appropriate temporospatial orientation.
  • b) Obtundation: A lesser degree of commitment is observed. The patient remains alert but exhibits difficulty in spatiotemporal orientation. There may be confusion, delirium, and thought process alterations.
  • c) Drowsiness: Decreased alertness is noted, with a tendency to fall asleep. Dysfunction in the reticular formation (superficial, medium, deep) may be present.
  • d) Coma: A severe alteration of the reticular formation is evident, leading to unconsciousness.

2. Language

Assessment involves evaluating cerebral hemispheres (reception, understanding, formulation of the message) and the organs responsible for the emission and articulation of words.

  • Aphasia (Dysphasia)
    • Motor or Broca’s: Verbal expression is affected, often due to a lesion in the third frontal gyrus.
    • Sensory or Wernicke’s: Impaired word comprehension, typically associated with a lesion in the temporoparietal area.
    • Central: Impairment of both language comprehension and expression, often due to extensive temporoparietal injuries.
    • Nominal: Difficulty in naming objects, linked to temporoparietal area dysfunction.
  • Dysarthria (Anarthria)

    Difficulty with phonation organs (lips, tongue, palate, larynx) is present. Language is preserved but distorted. This can be caused by extrapyramidal system injury (e.g., Parkinson’s disease, hepatolenticular degeneration), brainstem encephalopathy, cerebellar disease, or muscle disorders.

3. Cranial Nerves

  • I. Olfactory: Assesses the ability to perceive odors. Originates in the olfactory bulb and exits through the cribriform plate of the ethmoid bone.
  • II. Optic: Evaluated by an ophthalmologist, including fundus examination, perception, and visual field assessment. Enters through the optic chiasm and exits via the optic canal.
  • III. Oculomotor, IV. Trochlear, VI. Abducens (Eye Movement): These nerves innervate the muscles that move the eye: medial rectus, superior and inferior rectus, inferior oblique (oculomotor nerve), superior oblique (trochlear nerve), and lateral rectus (abducens nerve).
    • Diplopia: Double vision.
    • Conjugate Gaze Palsy: Difficulty in moving both eyes laterally (cortical lesion, internal capsule, or pons) or vertically (Parinaud syndrome, midbrain lesion).
    • Pupillary Dilation (Mydriasis): May indicate a third nerve lesion.
    • Pupillary Constriction (Miosis): May suggest damage to the cervical sympathetic pathway.
    • Anisocoria: Unequal pupillary dilation.
    • Argyll Robertson Pupil: Absence of pupillary light reflex.
  • V. Trigeminal: Assesses tactile sensation and pain in the face through its three branches: ophthalmic, maxillary, and mandibular. Concentric alteration may indicate a nuclear lesion.
    • Masseter Reflex: Abrupt closure of the mouth upon percussion of the mandible.
  • VII. Facial: Controls facial expression.
    • Upper Motor Neuron Lesion: Preserves movement of the forehead and orbicularis oculi muscles.
    • Lower Motor Neuron Lesion: Involves the entire hemiface, reduced taste in the anterior 2/3 of the tongue, hearing impairment, and altered reflexes (corneal reflex with the trigeminal nerve, nasopalpebral reflex upon stimulating closure of the eyelids, palmomental reflex, and Chvostek’s sign – facial contraction upon touching the face).
  • VIII. Vestibulocochlear: Responsible for hearing and balance.
    • Hearing: Hypoacusis or deafness may indicate a nerve problem (sensorineural hearing loss) or a problem with conductive structures (conductive hearing loss, assessed via Rinne and Weber tests).
    • Balance: Assessed through the patient’s gait (Romberg test).
    • Nystagmus: Rhythmic eye oscillations.
    • Vertigo: Can be subjective (in relation to the patient) or objective (in relation to surrounding objects).
  • IX. Glossopharyngeal: Mixed nerve responsible for gustatory sensitivity, pain, and touch in the posterior third of the tongue. Innervates the pharynx, mouth, and areas associated with the vagus nerve.
  • X. Vagus: Unilateral alteration of the vagus nerve, associated with ipsilateral glossopharyngeal involvement, leads to paralysis of the soft palate.
    • Bitonal Voice: Indicates vocal cord dysfunction.
    • Bilateral Lesion: May cause vomiting, abnormal pulse, blood pressure changes, and respiratory issues.
  • XI. Accessory: Innervates the trapezius and sternocleidomastoid muscles. Injury causes difficulty or inability to turn the head toward the healthy side and lift the shoulder.
  • XII. Hypoglossal: Controls tongue motility. Dysfunction leads to deviation of the tongue toward the diseased side, weak movements, atrophy, and fasciculations.

4. Motor System

  • Position: Assess for deficits, dystonia, irritability, and antalgic compensation.
  • Palpation: Evaluate muscle mass for fasciculations and atrophy.
  • Muscle Power: Assess for spontaneous movements or paresis.
  • Resistance: A decrease in force indicates partial paralysis, while a complete reduction in strength suggests complete paralysis.
  • Muscle Tone: Resistance offered by the muscle to joint displacement.
    • Hypotonia: Can be peripheral (spinal arch interruption) or central (inhibition of vestibulospinal facilitators).
    • Hypertonia: Can be spastic (decreases after initiation of movement, seen in pyramidal lesions), cogwheel-like (successive shocks, seen in extrapyramidal lesions), plastic (steady increase in tone, seen in Parkinson’s disease), or antalgic contractures (muscle contraction in response to painful stimuli).
  • Reflexes:
    • Musculoskeletal or Tendinous: Tendon percussion elicits contraction.
    • Superficial: Contraction of a specific muscle group.
    • Pathological: Indicate neurological injury.
    • Babinski Sign: Dorsiflexion of the big toe, suggesting pyramidal tract damage.
    • Frontal Lesions (Archaic Reflexes): May present with prehension, palmomental, and suction reflexes.
  • Coordination: Ataxia may indicate diseases of the cerebellum or its pathways.

5. Sensitivity

Assess touch, pain, temperature, posture, and vibration.

  • Dysesthesia: Abnormal perception.
  • Anesthesia: Absence of perception.