Neural substrates of executive dysfunction in fragile X-associated tremor/ataxia syndrome (FXTAS): a brain potential study.
Cereb Cortex
; 23(11): 2657-66, 2013 Nov.
Article
em En
| MEDLINE
| ID: mdl-22918986
ABSTRACT
Executive dysfunction in fragile X-associated tremor/ataxia syndrome (FXTAS) has been suggested to mediate other cognitive impairments. In the present study, event-related potentials and neuropsychological testing were combined to investigate the brain mechanisms underlying the executive dysfunction in FXTAS. Thirty-two-channel electroencephalography was recorded during an auditory "oddball" task requiring dual responses. FXTAS patients (N= 41, mean age= 62) displayed prolonged latencies of N1 and P3 and reduced amplitudes of P2 and P3, whereas their N2 measures remained within the normal range, indicating relatively preserved early-stage auditory attention but markedly impaired late-stage attention and working memory updating processes (as indexed by P3). Topographical mapping revealed a typical parietal P3 peak preceded by a prominent fronto-central P3 in normal control subjects (N= 32), whereas FXTAS patients had decreased parietal P3 amplitude and diminished fronto-central positivities with a delayed onset (â¼50 ms later than controls, P < 0.002). The P3 abnormalities were associated with lower executive function test (e.g., BDS-2) scores. Smaller P3 amplitudes also correlated with increased CGG repeat length of fragile X mental retardation 1 (FMR1) gene and higher FMR1 mRNA levels. These results indicate that abnormal fronto-parietal attentional network dynamics underlie executive dysfunction, the cardinal feature of cognitive impairment in FXTAS.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Córtex Cerebral
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Potenciais Evocados Auditivos
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Função Executiva
Tipo de estudo:
Risk_factors_studies
Idioma:
En
Revista:
Cereb Cortex
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
Estados Unidos