Davis Medical Center, MIND Institute, University of California, Sacramento, CA 95817 USA ; War Related Illness and Injury Study Center, Veterans Affairs Medical Center, Washington, DC 20422 USA.
Davis Medical Center, MIND Institute, University of California, Sacramento, CA 95817 USA.
J Neurodev Disord. 2014;6(1):45. doi: 10.1186/1866-1955-6-45. Epub 2014 Dec 11.
Fragile X premutation carriers (fXPCs) have an expansion of 55-200 CGG repeats in the FMR1 gene. Male fXPCs are at risk for developing a neurodegenerative motor disorder (fragile X-associated tremor/ataxia syndrome (FXTAS)) often accompanied by cognitive decline. Several broad domains are implicated as core systems of dysfunction in fXPCs, including perceptual processing of spatial information, orienting of attention to space, and inhibiting attention to irrelevant distractors. We tested whether orienting of spatial attention is impaired in fXPCs.
Participants were fXPCs or healthy controls (HCs) asymptomatic for FXTAS. In experiment 1, they were male and female children and adults (aged 7-45 years). They oriented attention in response to volitional (endogenous) and reflexive (exogenous) cues. In experiment 2, the participants were men (aged 18-48 years). They oriented attention in an endogenous cueing task that manipulated the amount of information in the cue.
In women, fXPCs exhibited slower reaction times than HCs in both the endogenous and exogenous conditions. In men, fXPCs exhibited slower reaction times than HCs in the exogenous condition and in the challenging endogenous cueing task with probabilistic cues. In children, fXPCs did not differ from HCs.
Because adult fXPCs were slower even when controlling for psychomotor speed, results support the interpretation that a core dysfunction in fXPCs is the allocation of spatial attention, while perceptual processing and attention orienting are intact. These findings indicate the importance of considering age and sex when interpreting and generalizing studies of fXPCs.
脆性 X 前突变携带者（fXPCs）在 FMR1 基因中具有 55-200 个 CGG 重复扩展。男性 fXPCs 有发展为神经退行性运动障碍（脆性 X 相关震颤/共济失调综合征（FXTAS））的风险，通常伴有认知能力下降。几个广泛的领域被认为是 fXPCs 中功能障碍的核心系统，包括空间信息的知觉处理、对空间的注意定向以及对无关干扰的注意抑制。我们测试了 fXPCs 中空间注意的定向是否受损。
参与者为 fXPCs 或无症状 FXTAS 的健康对照（HCs）。在实验 1 中，他们是男性和女性儿童和成人（年龄 7-45 岁）。他们根据自愿（内源性）和反射（外源性）线索来定向注意力。在实验 2 中，参与者为男性（年龄 18-48 岁）。他们在一个内源性线索任务中定向注意力，该任务操纵线索中的信息量。
在女性中，fXPCs 在内外源条件下的反应时间均慢于 HCs。在男性中，fXPCs 在外源条件下和具有概率线索的具有挑战性的内源性线索任务中的反应时间慢于 HCs。在儿童中，fXPCs 与 HCs 没有差异。
由于即使控制了精神运动速度，成年 fXPCs 的反应时间仍然较慢，因此结果支持了 fXPCs 核心功能障碍是空间注意力分配的解释，而知觉处理和注意力定向保持完整。这些发现表明，在解释和推广 fXPCs 的研究时，考虑年龄和性别非常重要。
