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

and executive functions to be impaired in adults. However, in this systematic review (more detailed and complete), they concluded that the proportion of adult patients with cognitive function impairment is as large as in children. Moreover, the authors could not identify specific determinants of cognitive deficits and deterioration, and urged for further studies to examine such questions, as well as the influence of revascularization treatment on cognitive functioning. The general recommendation for the future was extensive prospective studies using a standardized battery of neuropsychological tests to determine the severity of cognitive impairment and the domains affected, with the inclusion of information on school-level and performance, and on work status, since it reflects functionality rather than deficits [44].

Recent reports (following this metaanalysies) have followed in the same direction regarding the alteration of attention and executive functions. Jia-Bin et al. discovered that, in a sample of 34 MMD patients, one group performed significantly worse than controls in the Symbol Digit Modalities Test (z = 4.555, P < 0.001) and The Trail-Making Test Part B (z = 3.953, P < 0.001). An impairment of memory measured through the long-term delayed recall of the Auditory Verbal Learning Test (P < 0.001) was also observed [72]. A neurocognitive evaluation case report by Indorewalla et al. [73] showed a lateralized profile and impairments in simple auditory attention, processing speed, working memory, verbal learning, verbal fluency, and speeded fine-motor dexterity.

Importantly, the latest studies about cognition in adult MMD consider other factors, like gender and clinical subtypes [73]. Shi et al. [74] studied a sample of 49 patients divided into 12 hemorrhagic subjects and 37 with ischemia and compared them with healthy controls. All the patients displayed comprehensive cognitive impairment affecting the domain of memory (prospective and retrospective memory), verbal fluency and executive functions (measured with the Stroop test) [74]. They also showed a pattern of attention significantly different from controls (including impairment in the Trail Making Test-A). Interestingly, female patients performed better than male patients, showing significant differences in forward and immediate memory, Stroop and Wisconsin Card Sorting Test. Another intringuing result was that the hemorrhagic patients, fared poorer in the dimension of prospective and retrospective memory than their ischemic counterparts. Besides, prospective and retrospective memory, attention and executive functions were moderately correlated. A recent study exploring the clinical features of MMD sufferers compared 19 patients with a history of cerebral infarction with 21 asymptomatic patients (plus 20 healthy controls matched for age, sex, and years of education). Detailed neuropsychological testing revealed varying degrees of decline in intelligence, spatial imagination, verbal working memory and computational ability (simple and complex subtraction) in asymptomatic patients compared to normal controls. Patients with cerebral infarction showed more severe impairment in complex arithmetic and short-term memory than those without symptoms. In conclusion, the authors suggested that asymptomatic patients can present various cognitive impairments that precedes the onset of clinical signs such as cerebral infarction, which may be a long-term complication of conservative treatment. Future research should address in depth the distinctive profile of MMD patients according to their neurological clinical status, the influence of gender and educational level on their cognition, and the importance of functional independence in their rehabilitation.

Moyamoya disease and atherosclerotic cerebrovascular disease are chronic ischemic diseases with similar consequences in the form of vascular cognitive impairment. The aim of the study conducted by Su et al. [75] was to investigate the patterns of microstructural damage associated with vascular cognitive impairment in the two diseases in a sample of 34 patients with MMD (mean age 43.9),

27 patients with atherosclerotic cerebovascular disease (mean age: 44.6), and 31 normal controls (mean age 43.6) from Huashan Hospital of Fudan University, in China. Cognitive function was assessed using the Mini-Mental State Examination, long-term delayed recall of the Auditory Verbal Learning Test, the Trail-Making Test Part B, and the Symbol Digit Modalities Test. Single-photon emissioncomputed tomography was used to examine cerebral perfusion. Voxel-based morphometry and tract-based spatial statistics were performed to identify regions of gray matter atrophy and white matter deterioration in patients and controls. The results demonstrated that the severity of cognitive impairment in the two diseases was similar in all the tested domains. Both patients with MMD and those with atherosclerotic cerebrovascular disease exhibited altered supratentorial hemodynamics; gray matter atrophy was evident in the middle cingulate cortex and parts of the frontal gyrus in both groups, but was generally more severe and more diffuse in those with MMD. White matter deterioration was significant in both diseases, in the genu and body of the corpus callosum, the anterior and superior corona radiation, and the posterior thalamic radiation, but was more diffuse and more severe in MMD. Vascular cognitive impairment was associated with regional microstructural damage, with a potential link between gray and white matter damage being highlighted [75].

A last point of interest to mention is that MMD patients sometimes present with cognitive dysfunction and psychiatric or neuropsychiatric symptoms. In 1991, McDade described a rare case of schizophrenia in a 19-years-old boy with MMD [76]. Nagata et al. reported the case of a 50-year-old man who suffered from irritability and agitation that affected his work and relationships after developing a right ipsilateral frontal lobe infarction as a result of MMD [77]. Zalonis et al. described a case of a middle-aged woman who suffered intraventricular haemorrhages due to MMD. Initially, she presented psychiatric symptoms (mood disorder, irritability, or agitation) that did not respond to treatment. Neuropsychological assessment revealed underlying significant cognitive deficits, mostly of complex attention and speed of information processing, visuospatial and constructional abilities, verbal and nonverbal memory, and executive functions. These deficits continued to be present or had improved slightly when follow-up was carried out [78]. Hong et al. [79] described a patient (a 22-year-old, right-handed woman) who presented with transient cortical blindness, anosognosia, and global transitory amnesia associated with MMD. The woman completely denied blindness and recent memory disturbances with confabulation. This case report demonstrated that MMD can manifest itself in transient posterior circulation symptoms in the form of Dide-Botcazo syndrome [55]. Of the 29 adult American MMD patients included in the Festa et al. study, 36% were found to suffer mild depression and 28% to suffer moderate-tosevere depression, as measured by the Beck Depression Inventory (BDI) [55]. In their 2008 study, Karzmak et al. reported five patients with mild depression, and two patients with moderate depression, and later (in their 2012 study) reported clinically significant emotional distress (depression and/or anxiety) in (37% of their cohort) [62]. In summary, although exclusively psychiatric presentations of MMD in adults are exceedingly rare in the literature, complaints of depression or anxiety often do accompany new focal neurological symptoms, and psychosis can indeed occur. In this way, MMD carries with the risk of misdiagnosis as an affective or psychotic disorder. Transient ischemic events may be mistaken for anxiety and panic disorder, and so there is a call for careful screening of precipitating triggers and characterization of symptoms. When a MMD patient shows psychiatric clinical signs, in the absence of a family history (particularly one of psychotic illness), in combination with atypical features (age at onset, visual hallucinations), a neurological investigation is advised, namely MRI or M.R. angiography rather than C.T.
