Deep Tendon Reflexes (DTRs) Overview

Deep Tendon Reflexes (DTRs)

• DTRs assess the health of the nervous system.
• Normal reflexes suggest intact pathways, while abnormal reflexes may indicate issues such as nerve damage, spinal cord injury, or brain pathology.
• Hyperreflexia (exaggerated reflexes): Often seen in upper motor neuron lesions (e.g., stroke, multiple sclerosis).
• Hyporeflexia or Areflexia (diminished or absent reflexes): Typically seen in lower motor neuron lesions, peripheral neuropathy, or conditions like Guillain-Barré syndrome.
• Abnormal DTRs can help diagnose conditions such as:
  • Spinal cord injuries
  • Nerve root compression (radiculopathy)
  • Peripheral neuropathies
  • Myopathies
• Clinicians can localize lesions in the nervous system by testing specific reflexes (e.g., patellar, Achilles), as different reflexes correspond to different spinal cord levels.

Grading of DTRs

• DTRs are graded on a scale from 0 to 4+.
• 0: Absent reflex — No response, which may suggest a problem with the peripheral nervous system or nerve root.
• 1+: Hypoactive or diminished reflex — A slight but clearly present response, which may indicate a lower motor neuron lesion or peripheral neuropathy.
• 2+: Normal reflex — A typical response; this is the expected finding in a healthy individual.
• 3+: Hyperactive reflex without clonus — A brisk response that may be considered normal in some individuals or indicate a potential upper motor neuron lesion.
• 4+: Hyperactive reflex with clonus — A very brisk reflex response accompanied by repetitive muscle contractions (clonus), often indicating an upper motor neuron lesion, such as in cases of stroke or spinal cord injury.

Cranial Nerves Assessment

• Cranial Nerve I (Olfactory): Close eyes and smell test to assess sense of smell.
• Cranial Nerve II (Optic): Confrontation visual field test to assess visual acuity and peripheral vision.
• Cranial Nerves III, IV, VI (Oculomotor, Trochlear, Abducens): Six cardinal fields of gaze, pupils reaction to light (PERRLA), accommodation test to assess extraocular muscle control and pupillary reactions.
• Cranial Nerve V (Trigeminal): Patient clenches teeth to assess masseter and temporal muscle strength. Open mouth and apply resistance to assess jaw movement. Lightly touch the forehead, cheeks, and jaw to test facial sensation.
• Cranial Nerve VII (Facial): Patient closes eyes tightly, smiles, frowns, and puffs out cheeks to assess facial muscle movement.
• Cranial Nerve VIII (Vestibulocochlear): Occlude one ear, whisper from the opposite ear, and vice versa, to assess hearing.
• Cranial Nerve IX (Glossopharyngeal): Use a tongue depressor to elicit the gag reflex.
• Cranial Nerve X (Vagus): Assess for hoarseness and ability to swallow.
• Cranial Nerve XI (Accessory): Patient moves head side to side, up and down, and shrugs shoulders against resistance to assess shoulder and neck muscle strength.
• Cranial Nerve XII (Hypoglossal): Patient sticks out tongue and moves it side to side to assess tongue movement.

Plantar Reflex (Babinski Sign) (L5-S2)

• The sole of the foot is stroked from the heel to the toes along the lateral side using a blunt object.
• Normal Response: In adults, the toes should curl downward (flexion). In infants, or in cases of neurological damage, the toes may fan out and the big toe dorsiflexes (positive Babinski sign).
• Significance: A positive Babinski sign in adults is abnormal and may indicate an upper motor neuron lesion affecting the corticospinal tract.

This quiz will test your knowledge of Deep Tendon Reflexes (DTRs) and their significance in assessing nervous system health. You'll learn about the classification of reflex responses and their implications for diagnosing various neurological conditions. Prepare to explore how specific reflex tests indicate different spinal cord levels.