Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Via Olgettina, 60, 20132, Milan, Italy.
Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Azienda Ospedaliero-Universitaria Careggi, Florence, Italy.
J Neurol. 2019 May;266(5):1274-1279. doi: 10.1007/s00415-019-09298-w. Epub 2019 Mar 29.
To characterize patterns of language lateralization in a right-handed woman with nonfluent/agrammatic primary progressive aphasia (nfvPPA) clinical picture despite showing a prevalent right-sided brain damage.
We report a case of a 58-year-old woman with nfvPPA diagnosis (age at onset = 55) previously described as a crossed aphasia case with progranulin mutation. At 2 years from the first visit, patient underwent 3DT1-weighted and a task-based functional MRI (fMRI). During the fMRI task, she was asked to perform a letter fluency test as the task of interest and to count forward as the control condition. Image processing and data analysis were performed using SPM12 and the effect of each task was tested at p < 0.05 FWE corrected.
The structural MRI confirmed a widespread right fronto-temporal atrophy mainly involving the right inferior frontal gyrus. During the letter fluency task, we observed an increased activation centered at the right inferior orbitofrontal gyrus and right middle frontal gyrus. By reducing the threshold, the pattern of functional activation was still dramatically prevalent at the right side.
We provided evidence of the right language lateralization in a previously suspected crossed nfvPPA. Despite the long disease duration and the large amount of atrophy at the right side, there was no fMRI evidence of a left-hemisphere contribution to language function. We might speculate that compensatory effects do not appear when the premorbid language lateralization is purely right. The investigation of the underlying functional brain substrates in crossed nfvPPA cases may help understanding disease vulnerability in these neurodegenerative conditions.
描述一位右侧大脑损伤为主的右利手非流利/语法障碍型原发性进行性失语症（nfvPPA）患者的语言侧化模式。
我们报告了一例 58 岁女性患者，患有 nfvPPA（发病年龄为 55 岁），先前被描述为具有颗粒蛋白基因突变的交叉性失语症病例。在首次就诊后 2 年，患者接受了 3DT1 加权和任务型功能磁共振成像（fMRI）检查。在 fMRI 任务中，她被要求进行字母流畅性测试作为感兴趣的任务，并进行顺数计数作为对照条件。使用 SPM12 进行图像处理和数据分析，并在 p < 0.05 FWE 校正下测试每个任务的效果。
结构 MRI 证实了广泛的右侧额颞叶萎缩，主要累及右侧下额回。在字母流畅性任务中，我们观察到右眶额下回和右中额回的激活增加。降低阈值后，功能激活模式仍然明显偏向右侧。
我们提供了先前怀疑的交叉性 nfvPPA 右侧语言侧化的证据。尽管疾病持续时间长且右侧萎缩量大，但 fMRI 没有证据表明左半球对语言功能有贡献。我们可以推测，当语言侧化在病前就纯粹是右侧时，补偿效应不会出现。对交叉性 nfvPPA 病例的潜在功能脑基底的研究可能有助于理解这些神经退行性疾病中的易感性。
