Final Answer:
Nystagmus, an abnormal response, occurs when the eyes constantly look upward, regardless of which way the head is turned.
Step-by-step explanation:
Nystagmus: This is the correct term for the abnormal eye movement described in the question. Nystagmus refers to involuntary, rhythmic eye movements, and when the eyes consistently look upward despite head movements, it is considered an abnormal response.
Abnormal Response: The phrase "abnormal response" in the question is synonymous with the irregular eye movement mentioned, emphasizing that the typical eye movement response is not occurring.
Constantly Look Upward: This part clarifies the specific nature of the abnormal response—continuous upward gaze regardless of the direction in which the head is turned.
Regardless of Head Movement: This further specifies that the abnormal eye movement is not influenced by changes in head position, reinforcing the characteristic nature of nystagmus.