*Neuropsychology of Moyamoya Disease DOI: http://dx.doi.org/10.5772/intechopen.96558*

third evaluation revealed a fluctuating evolution. Executive function, PS, total I.Q., perceptual reasoning, and calculation were most consistently affected during the three assessments, which is consistent with the rest of the literature [39].

The impact on the quality of life of 30 children with MMD (with a median age of 13,5 years) was studied by Ball, Steinberg and Elbers using the Pediatric Quality of Life 4.0 Measurement Model [40]. The authors compared their quality of life to that of chronically ill children and children with stroke in order to better understand the impact of a diagnosis of MMD. The results showed that, even in the absence of stroke, children with moyamoya disease had a lower quality of life than healthy controls and a similar quality of life to chronically ill children and those with non–moyamoya disease stroke. The concluded that hildren with moyamoya disease would benefit from mental health support beyond what a mild physical presentation may indicate.

Assessment of neurological and neuropsychological outcome following revascularization, shows that surgical procedures are effective in halting the neurological progression and results in neuropsychological improvement in some patients [41]. For example, Nehra and Kaur in 2015 reported a male diagnosed with MMD at eight years old and, referred for neuropsychological evaluation at 12 years due to, impaired intellectual functioning with moderate retardation in adaptive social functioning. Two years after psychosocial intervention, the patient showed a remarkable upward trend in his adaptive social functioning and, a jump of 21 I.Q. points in his intellectual functioning [42]. In the same line, Cusin-Lamonica et al. reported the case of a girl of seven years old who suffered two episodes of stroke in the left and right temporal-parietal and left frontal areas that occurred until the age of six years and five months [43]. She presented signs of deterioration in oral and written language (syllabic-alphabetic), non-naming of all graphemes, low arithmetic and writing means, pre-first-grade reading skillsand psycholinguistic delay, and pre-school-level phonological processing skills. The psychological evaluation indicated a satisfactory intellectual level. Revascularization surgery and medication were prescribed.

Considering the infant's brain's developmental plasticity, extrinsic influences, such as psychological interventions for speech-language pathology, coupled with intrinsic influences, can alter the cortical organization and regenerate damaged connections, thus improving the compromised skills of children. A recent systematic review and metaanalysis of pMMD and aMMD, assessed the presence, severity, and nature of cognitive impairments in children and adults with MMD [44]. The authors revised data (collected between 1969 and 2016) pertaining to mean intelligence quotient and standardized z-scores of cognitive tests, and determined percentages of children and adults with cognitive deficits, before and after conservative or surgical treatment. In the case of pMMD, they included 11 studies reporting on a total of 281 children. In children, the median percentage with impaired cognition was 30% (range, 13% to 67%); the median I.Q. was 98 (rang: 71 to 107), and the median z-score was –0.39 for memory, and –0.43 for speed processing. The investigators concluded that many children (30%) with MMD suffer cognitive impairment, with modest to large deficits across various cognitive domains. Thus, extensive prospective studies with a standardized neuropsychological test battery are needed to determine the severity of cognitive impairment and the domains affected.

Recently, Kazumata et al. aimed to investigate cognitive function in the presurgical phase of pediatric patients with MMD with no apparent brain lesions in order to explore an association between cognitive function and cerebral blood flow [45]. They designed a prospective, observational, single-centre study, of 21 children (mean age 10 ± 3.0 years, range 5–14 years) diagnosed with MMD at Hokkaido

University Hospital between 2012 and 2018. A cross-sectional evaluation of intellectual ability was performed using the Wechsler Intelligence Scale for Children. rCBF was measured using [123I] N-isopropyl p-iodoamphetamine/SPECT. The associations among clinical factors, disease severity, regional cerebral blood flow (rCBF), and intelligence test scores were also examined. Results showed that the mean fullscale intelligence quotient (FIQ ) was 101.8 ± 12.5 (range 76–125) in children with no apparent brain lesions. A significant difference in the intelligence scale index score was observed most frequently (42.9%) between the working memory index (WMI) and verbal comprehension index. Regional CBF was significantly reduced both in the left and right medial frontal cortices compared to the cerebellum. There was a significant association of rCBF in the left dorsolateral prefrontal cortex (DLPFC) with FIQ, perceptual reasoning index, and processing speed index. Although average intellectual ability was not reduced in the children with MMD, the association of reduced rCBF in the left DLPFC and medial frontal cortex with FIQ, perceptual reasoning and processing speed suggests mild cognitive dysfunction due to cerebral hypoperfusion. Li et al. [46] studied the cognitive performance profile of twenty-one pMMD and its relationship with regional cerebral blood perfusion using arterial spin-labeling magnetic resonance and the Wechsler Intelligence Scale for Children. Results showed that six patients (28.6%) had no cognitive deficits in any index score, while 15 (71.4%) displayed cognitive deficits of varying severity. Nine (42.9%) patients showed overall cognitive impairment, and all cognitive index scores except for Verbal Comprehension Index were significantly lower than the mean scores of normative data than controls of the same age. Perceptual reasoning index was statistically lower in patients with radiologically confirmed cerebral infarction. The area of interest analysis revealed that the left temporal lobe's cerebral blood flow positively correlated with processing speed [46].

The causes of Moyamoya vasculopathy are still unknown, though it has been associated with various genetic conditions, including Neurofibromatosis type 1 (NF1). When moyamoya vasculopathy is present in the context of an associated condition, it is called "moyamoya syndrome," whereas moyamoya pathology in the absence of known associated risk factors is called "moyamoya disease" [47]. Studies have shown that a subset of patients with NF1 experience associated vascular conditions, with moyamoya syndrome representing one of the most common comorbidities. While NF1 and moyamoya syndrome are associated with neurocognitive deficits, very few neuropsychological data ara available for cases of comorbid NF1 and moyamoya syndrome, particularly pre- and post-re-vascularization surgery. To shed light on this topic, DeDios-Sterna and Ventura published in 2019 a single casestudy of a bilingual girl of Latin-American descendency with NF1 and moyamoya syndrome, who was assessed pre- (age five years, 9months) and post neurosurgery intervention (age six years, 1month). The pre-neurosurgical cognitive evaluation results documented significant deficits in sustained attention, daily executive functioning, and academic abilities, and the girl met ADHD-combined type criteria. Post- evaluation results revealed generally stable abilities with relative improvements in social, emotional, and behavioral functioning, but a relative decline in visuospatial skills, visual-spatial learning/memory, and executive functioning [48].

Existing literature supports attentional deficits in pMMD, but the clinical presentation of ADHD has rarely been reported. Due to chronic ischemic hypoxic insults to the cerebrum, these patients have poor working memory and experience difficulty sustaining attention, which is thought to be due tohypoperfusion of the frontal lobe. In this sense, Patra and Patnaik reported a clinical case of mental retardation and hyperactivity and inattention five years before the diagnosis of MMD. A definitive diagnosis was made at 11 years of age by means of digital subtraction angiography. The low intellectual functioning and ADHD might have
