Comprehensive Osteopathic Medical Licensing Examination (COMLEX USA) Practice

What is indicated by a DTR grade of 0?

1. Normal reflex response

2. Absent reflex response

3. Exaggerated reflex response

4. Hypoactive reflex response

The correct answer is: Absent reflex response

A deep tendon reflex (DTR) grade of 0 indicates an absent reflex response. This means that when a stimulus is applied to the tendon, there is no reflexive contraction of the muscle associated with that tendon, suggesting a potential neurological issue. The absence of reflexes can be indicative of several different conditions, such as peripheral neuropathy or spinal cord injury, where the pathways mediating the reflex response are disrupted. In contrast, other grades on the DTR scale indicate varying degrees of reflex activity. A normal reflex response would typically be graded as 2, indicating that the reflex is present and functioning as expected. Hypoactive reflex response would generally be graded as 1, pointing to reduced activity, while an exaggerated reflex response or hyperreflexia would be graded as 3 or 4, suggesting an overactive response due to possible central nervous system pathology. Thus, a DTR grade of 0 specifically denotes a complete absence of the reflex response, which can help clinicians gauge neurological function and identify potential issues within the reflex arc.