Akio Nakai

Publications (56) View all

• Article: http://dx.doi.org/10.1016/j.braindev.2012.01.005

  Akio Nakai
  Brain & development 05/2012; 34(5):408–409. · 1.74 Impact Factor
• Article: The Neurological Examination of the Child with Minor Neurological Dysfunction

  Akio Nakai
  Brain & development 05/2012; 34(5):408–409. · 1.74 Impact Factor
• Article: Focal EEG abnormalities might reflect neuropathological characteristics of pervasive developmental disorder and attention-deficit/hyperactivity disorder.

  Masao Kawatani, Michio Hiratani, Hiroshi Kometani, Akio Nakai, Hirokazu Tsukahara, Akemi Tomoda, Mitsufumi Mayumi, Yusei Ohshima
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  ABSTRACT: Neurophysiological characteristics in electroencephalograms (EEG) were investigated for patients with pervasive developmental disorder (PDD) and for patients with attention-deficit/hyperactivity disorder (AD/HD). This study examined 64 PDD children and 22 AD/HD children with no history of epilepsy or progressive neurological or psychiatric disorder. We used multivariate analysis to compare EEG abnormalities, clinical symptoms, and intelligence levels between PDD and AD/AD patient groups. Paroxysmal discharges at the frontopolar-frontal (Fp-F) brain regions and background EEG abnormalities tended to be detected preferentially in the PDD group, although paroxysmal discharges at central-temporal (C-T) regions tended to be detected preferentially in the AD/HD group. The paroxysmal discharges observed in patients expressing persistence and impulsivity are apparently localized respectively in the Fp-F and C-T regions. A combination of EEG abnormalities, including background EEG abnormalities and paroxysmal discharges at Fp-F and C-T regions, might be useful diagnostic hallmarks to distinguish PDD with AD/HD from AD/HD alone using a logistic regression model. The dysfunction of specific brain areas associated with EEG abnormalities might explain characteristics of clinical symptoms observed in PDD and AD/HD patients.
  Brain & development 01/2012; 34(9):723-30. · 1.74 Impact Factor
• Source

  Available from: Mirko Diksic

  Article: Brain regional α-[11C]methyl-L-tryptophan trapping in medication-free patients with obsessive-compulsive disorder.

  Alexandre Berney, Marco Leyton, Paul Gravel, Igor Sibon, Debbie Sookman, Pedro Rosa Neto, Mirko Diksic, Akio Nakai, Gilbert Pinard, Christo Todorov, Hidehiko Okazawa, Pierre Blier, Thomas Edward Nordahl, Chawki Benkelfat
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  ABSTRACT: The hypothesis of a serotonin (5-hydroxytryptamine [5-HT]) dysfunction in obsessive-compulsive disorder (OCD) stems largely from the clinical efficacy of 5-HT reuptake inhibitors. Serotonergic abnormalities in the unmedicated symptomatic state, however, remain to be fully characterized. To investigate brain regional 5-HT synthesis, as indexed by positron emission tomography and the α-[(11)C]methyl-L-tryptophan trapping constant (K*), in treatment-free adults meeting criteria for OCD. Between-group comparison. Department of Psychiatry and Montreal Neurological Institute, McGill University, and Department of Psychology, McGill University Health Centre, Quebec, Canada. Twenty-one medication-free patients with OCD (15 men with a mean [SD] age of 33.2 [9.3] years and 6 women with a mean [SD] age of 35.8 [7.1] years) and 21 healthy controls matched for age and sex (15 men with a mean [SD] age of 32.9 [10.1] years and 6 women with a mean [SD] age of 36.5.5 [8.6] years). Main Outcome Measure The α-[(11)C]methyl-L-tryptophan brain trapping constant K*, which was analyzed with Statistical Parametric Mapping (SPM8) and with proportional normalization (extent threshold of 100 voxels with a peak threshold of P ≤ .005). Compared with healthy controls, the patients with OCD exhibited significantly greater α-[(11)C]methyl-L-tryptophan trapping in the right hippocampus and left temporal gyrus (Brodmann area 20). In the larger subsample of all men, these same differences were also evident, as well as higher K* values in the caudate nucleus. Individual differences in symptom severity correlated positively with K* values sampled from the caudate and temporal lobe of the patients with OCD, respectively. There were no regions where the patients exhibited abnormally low K* values. Volumetric analyses found no morphometric alterations that would account for the group differences. The results support previous reports of greater striatal and temporal lobe activity in patients with OCD than in healthy controls and suggest that these disturbances include a serotonergic component. Previously reported glucose metabolic disturbances in OCD involving the orbitofrontal and cingulate cortices, in comparison, might reflect postsynaptic changes in the serotonergic system.
  Archives of general psychiatry 03/2011; 68(7):732-41. · 12.26 Impact Factor
• Article: A case of intracranial saccular aneurysm after primary varicella zoster virus infection.

  Masao Kawatani, Akio Nakai, Takashi Okuno, Hirokazu Tsukahara, Yusei Ohshima, Mitsufumi Mayumi
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  ABSTRACT: We report a case of intracranial saccular aneurysm that developed 3years after post-varicella ischemic stroke. A 6-year-old girl without apparent immunologic defects presented with right hemiparesis and expressive aphasia 1month after chickenpox. Her magnetic resonance imaging scans revealed left basal ganglia infarction because of left lenticulostriate artery occlusion. Although her neurologic symptoms improved gradually, segmental irregular narrowing remained in the A1 and M1 segments of the left anterior and middle cerebral arteries, respectively. Three years later, the follow-up magnetic resonance angiography indicated saccular aneurysm in the anterior communicating artery and the anti-VZV IgG antibody index in the cerebrospinal fluid was elevated. Subclinical reactivation of VZV and the segmental vascular narrowing might cause intracranial aneurysm, even in immunocompetent children.
  Brain & development 03/2011; 34(1):80-2. · 1.74 Impact Factor