Have you ever heard of the Animal Naming Test (ANT)? To me, it sounds like a game you might play with kids on an elementary school playground! I had never heard the term until I read through the latest Clinical Practice Guideline on the Management of Hepatic Encephalopathy (HE). The ANT is a quick, easy, and reliable verbal questionnaire used to assess for minimal or covert hepatic encephalopathy (MHE). It doesn’t require any special equipment and can be administered in an outpatient setting or at the bedside.
 
You may recall, HE is a neurological abnormality caused by liver dysfunction and marked by changes in personality, consciousness, cognition, and motor function (Weissenborn, 2019). MHE is a mild form of HE in patients with cirrhosis of the liver. MHE can be difficult to diagnosis as mental status irregularities may not be detected upon routine physical examination. The ANT evaluates cognitive functions such as verbal recall, retrieval, and self-monitoring (i.e., tracking animal names already stated), skills that require intact memory and executive functions.

How to Perform the Animal Naming Test

Agarwal and colleagues (2020) describe the ANT as follows:

• Ask the patient to say as many animal names as possible in one minute.
• Record the patient’s responses.
• If the patient stops before 1 minute, ask if there are any more animals they would like to add.
• If the patient does not speak for 15 seconds, give them a hint. For example, “A tiger is an animal. Can you name any more animals?”
• After 1 minute, count all responses excluding repeated and non-animal words.

In clinical studies, the ANT correlated with the Psychometric Hepatic Encephalopathy Score (PHES), the current recommended test for MHE consisting of six tests that take approximately 10 to 15 minutes to administer (Rodenbaugh et al., 2020; Agarwal et al., 2020). However, PHES is time-consuming and often impractical as the test must be conducted by a neuropsychologist (Rodenbaugh et al., 2020). ANT also correlated with the severity of liver disease assessed using the Model of End-Stage Liver Disease (MELD) and Child-Turcotte-Pugh (CTP) scores (Agarwal et al., 2020).
 
Campagna and colleagues (2017) found that the ANT was affected by limited education (less than 8 years) and advanced age (greater than 80 years of age). They developed an age and education adjusting procedure and created the simplified ANT (S-ANT). Using the S-ANT, the team broke down the scoring into three tiers:

• 0 = S-ANT greater than or equal to 15
• 1 = S-ANT between 10 and 15
• 2 = S-ANT less than 10

The S-ANT tool may be used to detect MHE in patients with cirrhosis in clinical practice. A score of 15 or more correlates with normal cognitive function. A score between 10 and 15 indicates mild cognitive impairment requiring further evaluation. An S-ANT value of 10 or lower strongly indicates deficient cognition and may be associated with the development of overt HE among individuals with cirrhosis (Tapper et al., 2022).
 
Next time you encounter a patient with a history of liver cirrhosis and a normal neurologic examination, suggest or try administering the Animal Naming Test. Let us know how well it worked in the comments below.
 

References:
 
Agarwal, A., Taneja, S., Chopra, M. Duseja, A., & Dhiman, R.K. (2020). Animal Naming Test – a simple and accurate test for diagnosis of minimal hepatic encephalopathy and prediction of overt hepatic encephalopathy. National Library of Medicine, National Institute of Health. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7380476/
 
Campagna, F., Montagnese, S., Ridola, L., Senzolo, M., Schiff, S., De Rui, M., Pasquale, C., Nardelli, S., Pentassuglio, I., Merkel, C., Angeli, P., Riggio, O., & Amodio, P. (2017). The animal naming test: An easy tool for the assessment of hepatic encephalopathy. Hepatology (Baltimore, Md.), 66(1), 198–208. https://doi.org/10.1002/hep.29146
 
Labenz, C., Beul, L., Toenges, G., Schattenberg, J. M., Nagel, M., Sprinzl, M. F., Nguyen-Tat, M., Zimmermann, T., Huber, Y., Marquardt, J. U., Galle, P. R., & Wörns, M. A. (2019). Validation of the simplified Animal Naming Test as primary screening tool for the diagnosis of covert hepatic encephalopathy. European journal of internal medicine, 60, 96–100. https://doi.org/10.1016/j.ejim.2018.08.008
 
Rodenbaugh, D., Vo, C. T., Redulla, R., & McCauley, K. (2020). Nursing Management of Hepatic Encephalopathy. Gastroenterology nursing : the official journal of the Society of Gastroenterology Nurses and Associates, 43(2), E35–E47. https://doi.org/10.1097/SGA.0000000000000434
 
Tapper, E. B., Kenney, B., Nikirk, S., Levine, D. A., & Waljee, A. K. (2022). Animal Naming Test Is Associated With Poor Patient-Reported Outcomes and Frailty in People With and Without Cirrhosis: A Prospective Cohort Study. Clinical and translational gastroenterology, 13(1), e00447. https://doi.org/10.14309/ctg.0000000000000447
 
Weissenborn K. (2019). Hepatic Encephalopathy: Definition, Clinical Grading and Diagnostic Principles. Drugs, 79(Suppl 1), 5–9. https://doi.org/10.1007/s40265-018-1018-z