Metabolic Medicine- Royal Liverpool Hospital

 

Why should I do the tests?

    • Patients with alkaptonuria (AKU) who attend the National AKU Centre (NAC) at the Royal Liverpool University Hospital are prescribed a drug called nitisinone, which is effective in managing AKU (and other tyrosine-related conditions).

A white container with a label next to a boxAI-generated content may be incorrect.

  • Nitisinone can raise tyrosine levels in the body. High tyrosine may, in some cases, affect how you think (cognitive ability). Following a protein-adjusted diet and being regularly monitored helps keep tyrosine levels within a healthy range.
  • Further monitoring (to safeguard your cognitive ability) involves psychometric testing using the Wechsler Adult Intelligence Scale (WAIS-IV).

Wechsler Adult Intelligence Scale (WAIS-IV)

  •   The WAIS-IV is the most widely used, reliable and valid intelligence quotient (IQ) test for adults (aged 16-90).
  •   It is made up of ten subtests which measure cognitive ability in four areas (indices): verbal comprehension (VCI), perceptual reasoning (PRI), working memory (WMI) and processing speed (PSI).

Wechsler Adult Intelligence Scale - Fourth UK Edition

  •   Completing the WAIS-IV takes about 90 minutes.
  •   If individual index scores are similar a full scale IQ (FSIQ) score or a general ability index (GAI) score can be obtained. If, however, the individual index scores vary a lot it is more meaningful to report only these.
  •   Further information on the WAIS-IV is available from the test provider Pearson: https://www.pearsonclinical.

Examples of tests and use of indices

A notebook with a graph on itAI-generated content may be incorrect.                                              A group of red and white cubesAI-generated content may be incorrect.

       Matrix reasoning                                                               Block design

  •   The perceptual reasoning index (PRI) is more appropriate than the verbal comprehension index (VCI) for those patients for whom English is an additional language.

Individual monitoring

  •   Patients’ responses to the questions are recorded, calculated and converted into test scores.
  •  The scores are recorded and interpreted in a table.
  •  Patients’ post-treatment scores are compared with their baseline (timepoint one, pre-treatment) scores to see whether there has been a change in cognitive ability over time.
  •  A small difference in scores can be expected through random variation, but where there is a larger change this can indicate a significant change in cognitive ability over time.

Group monitoring

  •  The average (mean) IQ score for the whole group of patients at the NAC has been calculated, and it reflects that of the general population (100). In other words, the group’s mean IQ score is normal.

A graph with a black lineAI-generated content may be incorrect.

  •  The group’s test scores for timepoint one and for all subsequent timepoints are being analysed to identify any changes in (indices of) cognitive ability over time.
  •  To date there has been no decline in the group’s cognitive ability over time.

Feedback

Your feedback is important to us and helps us influence care in the future. Following your discharge from hospital or attendance at your outpatient appointment you will receive a text asking if you would recommend our service to others. Please take the time to text back, you will not be charged for the text and can opt out at any point. Your co-operation is greatly appreciated.

Further Information                   

​​​​​​​

If you have any questions please contact:

Pam Clarke

Service Psychologist

National AKU Centre

Royal Liverpool University Hospital

​​​​​pam.clarke4@liverpoolft.nhs.uk

 

Telephone number: 0151 706 4289

Text phone number:  18001 0151 706 4289

 

Author: AKU Team/ Metabolic Medicine

Review date: March 2029

PI 3237 V1