Deep Tendon Reflex: The Tools and Techniques. What Surgical Neurology Residents Should Know

Ooi Lin-Wei; Leonard Leong Sang Xian; Vincent Tee Wei Shen; Chee Yong Chuan; Sanihah Abdul Halim; Abdul Rahman Izani Ghani; Zamzuri Idris; Jafri Malin Abdullah

doi:10.21315/mjms2021.28.2.5

Deep Tendon Reflex: The Tools and Techniques. What Surgical Neurology Residents Should Know

Malays J Med Sci. 2021 Apr;28(2):48-62. doi: 10.21315/mjms2021.28.2.5. Epub 2021 Apr 21.

Authors

Ooi Lin-Wei^{1

2

3}, Leonard Leong Sang Xian^{1

2

4}, Vincent Tee Wei Shen², Chee Yong Chuan^{1

5

2}, Sanihah Abdul Halim^{1

5

2

6}, Abdul Rahman Izani Ghani^{1

2

6}, Zamzuri Idris^{1

2

6}, Jafri Malin Abdullah^{1

2

6}

Affiliations

¹ Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia.
² Hospital Universiti Sains Malaysia, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia.
³ Department of Neurosurgery, Hospital Umum Sarawak, Kuching, Sarawak, Malaysia.
⁴ Department of Neurosurgery, Hospital Sungai Buloh, Sungai Buloh, Selangor, Malaysia.
⁵ Neurology Unit, Department of Internal Medicine, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia.
⁶ Brain Behaviour Cluster, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia.

Abstract

The deep tendon reflex (DTR) is a key component of the neurological examination. However, interpretation of the results is a challenge since there is a lack of knowledge on the important features of reflex responses such as the amount of hammer force, the strength of contraction, duration of the contraction and relaxation. The tools used to elicit the reflexes also play a role in the quality of the reflex contraction. Furthermore, improper execution techniques during the DTR assessment may alter the findings and cloud the true assessment of the nervous system. Therefore, understanding the basic principles and the key features of DTR allows for better interpretation of the reflex responses. This paper discusses the brief history of reflexes, the development of the reflex hammer, and also the key features of a reflex response encompassing the amplitude of force needed to elicit a reflex response, the velocity of contraction, the strength of contraction, and the duration of contraction and relaxation phases. The final section encloses the techniques of eliciting DTR in the upper extremities, trunk, and lower extremities, and the interpretation of these reflexes.

Keywords: Achilles reflex; afferent; biceps reflex; brachioradialis reflex; contraction time; deep tendon reflex; effector; knee jerk; muscle spindle; myotatic reflex; nervous system; peripheral nerve; reflex hammer; reflex torque; relaxation time; spinal cord; striking point; tapping force; technique.