Testing deficits in behavioural planning, set- shifting/ cognitive flexibility and working memory in children with high levels of Attention Deficit/Hyperactivity Disorder symptoms.Ukuhlola ukusilela ekuhlelweni kokuziphatha, ukuguquka ngokuqonda/ukuseka ukushintsha kanye nenkumbulo yokusebenza ezinganeni ezinamazinga aphezulu ezimpawu ze-ADHD.
Attention Deficit/Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder characterised by age-inappropriate symptoms of inattention, impulsiveness and hyperactivity that persist into adulthood. The symptoms are thought to result from a deficit in executive functions (EFs), such as inhibition, working memory, planning and set-shifting or cognitive flexibility. The study was aimed at investigating deficits in behavioural planning, cognitive flexibility and working memory in children with ADHD, with the use of specific neuropsychological tests, designed to measure deficiencies in the cortical areas of EFs, and compare this performance with a neurotypical control group. Further, the study investigated whether commonly used EF measurements were able to predict the core symptoms of ADHD. One hundred and fifty-six Sepedi and Xitsonga speaking primary school children (78 with ADHD and 78 matched controls without ADHD) aged between 6 and 15 years (M=11.7 years, SD=1.7), both males and females, participated in the study. The Tower of London (ToL) was used to measure planning, Memory for Digits (MFD) was used to measure working memory, Trail Making Test (TMT) to measure cognitive flexibility and Wisconsin Card Sorting Test (WCST) to measure set-shifting. Our results showed that, on the ToL, children with ADHD, especially ADHD-PI and ADHD-C, used more moves and took a longer time to complete the task compared to the neurotypical controls. There were no differences in the number of moves and time taken by the ADHD-HI when compared to controls. Further, the results showed that, on theWCST, children with ADHD presentations /subtypes (ADHD-Hyperactive/impulsiveness, ADHD-Inattention and ADHD-combined) met with more set-shifting problems than the neurotypical comparison group, as they made more total errors, perseverative responses, perseverative errors and nonperseverative errors. Children with ADHD also exhibited poorer performance on both the Digits Backwards (DB) and Trails-B when compared to the control group. No significant effect between the ADHD and control group were found on the Trails-A test. Sex and age did not influence the performance of set-shifting, working memory and cognitive flexibility tasks. All the tests (ToL, DF and DB, Trails-B and WCST) were found to predict ADHD symptomatology, except Trails-A. The WCST (total errors and perseverative errors) was the best predictor of ADHD symptomatology and H/I, followed by DB and Trails-B which predicted more inattention. In conclusion, the study revealed behavioural planning, set-shifting and working memory deficits in children with ADHD compared to neurotypical comparisons. The study also showed commonly used EFs tests could predict ADHD symptomatology. Since children with ADHD show behavioural planning, cognitive flexibility and working memory deficiencies which affect their academic and social functioning, it is recommended that tests of EF are included in the assessment to complement the diagnosis of ADHD. Iqoqa Isifo sokuba nenkinga yokugxila kulokhu okwenziwayo, i-Attention Deficit-Hyperactivity Disorder (ADHD) yisifo esijwayelekile esithinta ingqondo esihambelana neminyaka ethize. Izimpawu zaso ukuhluleka ukugxila kokwenziwayo, amatata, nokuqina kakhulu okuqhubeka kuze kube sebudaleni. Izimpawu zaso kukholakala ukuthi zihambelana nokuhluleka ukwenza izinto ezibalulekile empilweni, ezaziwa nge-executive functions (EFs), ezintweni ezifana nokuziqoqa, ukukhumbula izinto, ukuhlela nokuhlunga izinto engqondweni. Lolu cwaningo beluhlose ukucubungula ubuthakathaka bokukwazi ukubamba indlela yokuziphatha, ukukwazi ukucabanga ngokuvulelekile, nokukhumbula izinto ezinganeni eziphila ne-ADHD, kusetshenziswa indlela yokuhlola ingqondo, eyenzelwe ukukala izinga lobuthakathaka ezindaweni zomqondo i-EFs, kuqhathaniswe ukusebenza kwazo nalezo zingane ezinezinkinga ezihambelana nemizwa. Futhi, lolu cwaningo belucubungula ukuthi ingabe indlela ejwayelwe ukusetshenziswa yokukala i-EF iyakwazi yini ukuqagula izimpawungqo ze-ADHD. Izingane zesikole zamabanga aphansi eziyikhulu namashumi ayisihlanu nesithupha (ezingama-78 zazo zine-ADHD kanti ezingama-78 azinayo i-ADHD) ezineminyaka esukela kweyi-6 kuye kweyi-15 (M=11.7 eminyaka, SD=1.7), zobulili besilisa nobesifazane, ezikhuluma izilimi iSepedi neXitsonga, zazibandakanya nalolu cwaningo. Kwasetsheziswa indlela yokukala ebizwa nge-Tower of London (ToL) ukukala ukukwazi ukuhlela izinto, ukukwazi ukukhumbula, i-Memory for Digits (MFD), ukukala ukuthi ukukhumbula abanako ngokwesikhathi esingakanani. Kanti i-Trail Making Test (TMT) yona yasetshenziswa ukukala ukucabanga ngokukhululeka, bese i-Wisconsin Card Sorting Test (WCST) yona yakala ukukwazi ukuhlukanisa izinto. Imiphumela etholakele iveza ukuthi izingane ezine-ADHD ikakhulukazi i-ADHD-PI ne-ADHD-C zathatha isikhathi esithe xaxa ukwenza umsebenzi ezazinikezwe wona uma ziqhathaniswa nalezo ezingenayo i-ADHD. Kanti awukho umehluko owaba khona mayelana nesikhathi ezinganeni ezine- ADHD-HI uma kuqhathaniswa nalezo ezingenayo. Okunye okwavela ukuthi izingane ezine-ADHD zaziba nenkinga yokuhlukanisa izinto kunalezo zingane ezazinenkinga yemizwa ngenxa yamaphutha amaningi ezaziwenza kanye nokungakwazi ukuhluza kahle imicabango yazo. Izingane ezine-ADHD zazibuye zibe nenkinga yokufunda izinombolo ezihlanazelwe, i-Digits Backwards (DB) ne-Trails-B uma kuqhathaniswa nezingane ezingenayo. Awukho umehluko ongako nokho phakathi kwezingane ezine-ADHD nezingenayo mayelana nesivivinyo se-Trails-A. Ubulili kanye neminyaka akwenzanga mehluko ekukwazini ukuhlukanisa izinto, ukukhumbula nokwenza imisebenzi edinga ukucabanga ngokuvulelekile. Izivivinyo zonke (ToL), i-DF ne-DB, i-Trails-B ne-WCST kwahlonzwa njengezinto ezikwaziyo ukuqagula izimpawu ze-ADHD, ngaphandle kwe-Trails-A. I-WCST (inani lamaphutha nokugcina ulwazi) yayiyindlela engcono kakhulu ukuqagula izimpawu ze-ADHD ne-H/I, ilandelwe yi-DB ne-Trails-B eyaveza kakhulu ukuhluleka ukugxila kokwenziwayo. Uma sekuphethwa, lolu cwaningo luveze izinkinga zokuhlela, ukukwazi ukuhlukanisa, kanye nokukhumbula ezinganeni ezine-ADHD uma kuqhathaniswa nalezo ezinenkinga yezemizwa. Lolu cwaningo luphinde lwaveza ukuthi indlela ejwayelwe ukusetshenziswa yokukala i-EFs iyakwazi ukuqagula izimpawu ze-ADHD. Njengoba izingane ezine-ADHD zikhombisa ukuba nenkinga yokuhlela, eyokucabanga ngokuvulelekile nokukhumbula okuyizinto ezinomthelela ezifundweni zazo nasekwazini ukuphilisana nabanye abantu, kunconcwa ukuba indlela yokuhlola ye-EF isetshenziswe uma kuhlohlwa i-ADHD.
Doctoral Degrees. University of KwaZulu-Natal, Durban.