Neurocognitive disorders, previously not featured in the psychiatric nomenclature such as the Diagnostic and Statistical Manual of Mental Disorders (DSM), have now been included in the latest, fifth edition of the DSM. There is a dearth of studies on neurocognitive disorders among non-western population.

The aim of this study is to compare neuropsychological functioning measured by tests of executive function and cognition among patients marked by apathy and impulsivity following a traumatic brain injury in a non-Western population, Oman.

Comparing the performance of various neurocognitive indices including negativistic features and disinhibition, which were identified using the symptom checklists Apathy Evaluation Scale and Disinhibited Evaluation Scale. Comparative neurocognitive measures included tapping verbal reasoning ability (Raven's Standard Progressive Matrices), working memory (Digit Span–Digit Forward–Digit Backward); Buschke Reminding Test, planning/goal-directed (Controlled Oral Word Association Test–verbal fluency, Tower of London(–planning time–number solved), (Wisconsin Card Sorting Test–perseverative errors, and–number of categories solved), and affective ranges (Hospital Anxiety and Depression Scale).

Analysis showed that those participants who scored highly at Apathy Evaluation Scale and Disinhibited Evaluation Scale did not differ on indices measuring working memory/attention and affective ranges except for one measure: Digit span-Digit Forward. In the measures operationalized here to tap planning/goal-directed behaviour, the two cohorts differ on all indices except for Tower of London-Number Solved.

This study lays ground for further scrutiny in delineating the different characteristics of what previously labelled as frontal dysexecutive phenotype. It indicates that apathetic and disinhibited temperaments marked with specific neuropsychological performance.

The author has not supplied his/her declaration of competing interest.