Abstract
Hyperphenylalaninemia-related, subtle deficits of attention and of working memory are often reported in adolescents with phenylketonuria. Focused neuropsychological tests can be used to detect such deficits and to confirm the presence of poor metabolic control in the periods between routine blood phenylalanine tests, which are rarely performed in many patients from this age group due to their low treatment adherence.
We assessed the practical value of the d2 test of attention and of the Benton visual retention test for identification of teenagers, who have a high risk of brain dysfunction due to hyperphenylalaninemia. We analyzed the correlation between neuropsychological test scores achieved by 30 patients and their blood phenylalanine profiles since the neonatal period.
We observed strong correlation between the Concentration Performance scores on the d2 test and the quality of metabolic control within last month prior to the follow-up visit in the outpatient clinic (r = −0.72; p = 0.0003). The mean z-score was significantly higher in patients with good metabolic control than in those with poorly controlled hyperphenylalaninemia (0.44 vs. −1.12; p = 0.00002). On contrary, the results of the Benton visual retention test did not correlate significantly with the individual blood phenylalanine profiles.
We believe that neuropsychological assessment should be used in adolescents with phenylketonuria on a regular basis in order to increase the self-awareness in these patients and, consequently, to increase their treatment adherence and safety. The d2 test can be effectively used for detection of attention deficits and seems to be a valuable supplementary procedure for routine follow-up.
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Abbreviations
- Phe:
-
Phenylalanine
- PKU:
-
Phenylketonuria
- SD:
-
Standard deviation
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Communicated by: Avihu Boneh, MD, PhD, FRACP
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Take-Home Message
The d2 test, a classic neuropsychological paper-and-pencil diagnostic tool, can be used for assessment of dynamics of attention deficits, which are typically observed in patients with phenylketonuria.
Corresponding Author (the Guarantor of the Article)
Prof. Miroslaw Bik-Multanowski, MD, PhD, Department of Medical Genetics, ul. Wielicka 265, 30-336 Kraków, Poland; e-mail: miroslaw.bik-multanowski@uj.edu.pl.
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Conflict of Interest
Bozena Didycz, Magdalena Nitecka and Miroslaw Bik-Multanowski declare that they have no conflict of interest.
Informed Consent
All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2000 (5). Informed consent was obtained from all patients for being included in the study.
Contributions of Individual Authors
BD designed the study, collected and analyzed data, and wrote the manuscript, MN performed the psychological tests, contributed to data analysis and consulted the manuscript, MBM helped to design and supervised the study, consulted and partially modified the methodology, contributed to data analysis and to drafting of the manuscript.
Ethics Approval
The study was approved by the regional Ethics Committee (29/KBL/OIL/2011).
Funding
This work was supported by the Nutricia Research Foundation (grant number 02/2011).
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Didycz, B., Nitecka, M., Bik-Multanowski, M. (2017). The Use of d2 and Benton Tests for Assessment of Attention Deficits and Visual Memory in Teenagers with Phenylketonuria. In: Morava, E., Baumgartner, M., Patterson, M., Rahman, S., Zschocke, J., Peters, V. (eds) JIMD Reports, Volume 40. JIMD Reports, vol 40. Springer, Berlin, Heidelberg. https://doi.org/10.1007/8904_2017_60
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DOI: https://doi.org/10.1007/8904_2017_60
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