Prior studies have shown that procedural learning is severely impaired in patients with diffuse cerebellar damage (cortical degeneration) as measured by the serial reaction time task (SRTT). We hypothesize that focal cerebellar lesions can also have lateralized effects on procedural learning. Our objective was to assess the effects of focal cerebellar lesions in procedural learning as measured by the SRTT. We studied 14 patients with single, unilateral vascular lesions in the territory of the posterior-inferior or superior cerebellar artery, who were compared with ten age- and sex-matched controls in a one-handed version of the SRTT. Patients with lesions at any other level of the brain or posterior fossa were excluded by cranial magnetic resonance imaging. Our results show that patients do not acquire procedural knowledge when performing the task with the hand ipsilateral to the lesion, but show normal learning with the contralateral hand. No correlation was found with the side, size, or vascular territory of the lesion. We conclude that procedural learning is impaired in hemispheric cerebellar lesions and involves only the hand ipsilateral to the lesion, which suggests a critical role for the cerebellum and/or crossed cerebellar-prefrontal connections in this type of learning.

Objectives:To examine the efficacy of an integrative cognitive training program (REHACOP) to improve cognition, clinical symptoms, and functional disability of patients with Parkinson disease (PD).Methods:Forty-two patients diagnosed with PD in Hoehn & Yahr stages 1 to 3 were randomly assigned to either the cognitive training group (REHACOP) or the control group (occupational activities) for 3 months (3 sessions, 60 min/wk). Primary outcomes were change on processing speed, verbal memory, visual memory, executive functioning, and theory of mind. Secondary outcomes included changes on neuropsychiatric symptoms, depression, apathy, and functional disability. The trial was registered with clinicaltrials.gov (NCT02118480).Results:No baseline group differences were found. Bootstrapped analysis of variance results showed significant differences in the mean change scores between the REHACOP group and control group in processing speed (0.13 [SE = 0.07] vs −0.15 [SE = 0.09], p = 0.025), visual memory (0.10 [SE = 0.10] vs −0.24 [SE = 0.09], p = 0.011), theory of mind (1.00 [SE = 0.37] vs −0.27 [SE = 0.29], p = 0.013), and functional disability (−5.15 [SE = 1.35] vs 0.53 [SE = 1.49], p = 0.012).Conclusions:Patients with PD receiving cognitive training with REHACOP demonstrated statistically significant and clinically meaningful changes in processing speed, visual memory, theory of mind, and functional disability. Future studies should consider the long-term effect of this type of intervention. These findings support the integration of cognitive training into the standard of care for patients with PD.Classification of evidence:This study provides Class II evidence that for patients with PD, an integrative cognitive training program improves processing speed, visual memory, theory of mind, and functional disability.

By combining different neuroimaging techniques and cognitive data, results showed that functional connectivity alteration between the regions of the DMN is associated with lower cognitive performance and gray and white matter abnormalities in PD.

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