Decision-Making Impairment May Precede Limb Apraxia in Corticobasal Degeneration

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Back to table of contents Previous article Next article LettersFull AccessDecision-Making Impairment May Precede Limb Apraxia in Corticobasal DegenerationMichele Poletti, M.D., and Ubaldo Bonuccelli, M.D.Michele PolettiSearch for more papers by this author, M.D., and Ubaldo BonuccelliSearch for more papers by this author, M.D.Published Online:1 Apr 2011AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail To the Editor: Corticobasal degeneration (CBD) is characterized by asymmetric akinesis and rigidity, dystonia of the upper limb, apraxia, myoclonus, and dementia.1 Even if cognitive deficits, in particular of executive functions, are associated with CBD,2 no findings are available about orbitofrontal executive functions,2 usually assessed by decision-making tasks, such as the Iowa Gambling Task (IGT).3 In our movement-disorder tertiary clinic, we consecutively assessed patients who present signs compatible with a diagnosis of Parkinson's disease4 or parkinsonism with this task. Two of these patients, initially diagnosed with parkinsonism, subsequently developed a manifest upper-limb apraxia and were clinically diagnosed with CBD.One patient, Ms. DB, 60 years old, came to our attention in April 2008 for symptoms of bradykinesia and left upper-limb rigidity. She underwent a DaT-SCAN SPECT (bilateral hypocaptation in both putamen nuclei, more marked on the right), an RMI (showing diffuse cortical atrophy, more marked in the right parietal-prefrontal-insular cortex), and an 18-FDG-PET (mild hypometabolism in the right temporo-prefrontal cortex, the right ventral temporal cortex, and the right thalamus). Cognitively, she presented mild executive dysfunction. In March 2009 she developed a left upper-limb apraxia (Movement Imitation Test5: normal score >62; right upper limb: 67; left upper limb: 26). In November 2009 apraxia also affected the right upper limb (Movement Imitation Test: right upper limb: 47; left upper limb not assessable).Another patient, Mr. EH, a 66-year-old, right-handed man, came to our attention in September 2007 for symptoms of bradykinesia and right upper-limb rigidity. He underwent a DaT-SCAN SPECT (bilateral hypocaptation in both putamen nuclei, more marked on the left, and in the left caudate nucleus) and an 18-FDG-PET (marked bilateral hypometabolism in the parieto-prefrontal cortex, more marked on the left). He presented mild impairment of memory and executive functions. In January 2009 he developed a marked right-limb apraxia (Movement ImitationTest5: left upper limb: 63; right upper limb: 20).During their baseline assessments, at the onset of parkinsonism and before the appearance of upper-limb apraxia, both CBD patients performed the IGT, and were unable to develop a strategy of choice from more advantageous decks along the task. Mr. EH received a final score of 0, choosing equally from advantageous and disadvantageous decks in the latter two blocks of choices. Ms. DB received a positive final score (+18), selecting almost all advantageous decks in Blocks 2 and 5 and selecting almost all disadvantageous decks in Block 4. This pattern reflected more impulsive, perseverative behavior than a progressive development of an explicit strategy of choice. Instead, patients with de novo Parkinson's disease were able to develop a strategy of choice from more advantageous decks along the IGT.4 These neuropsychological findings suggest that, in CBD patients, decision-making may be impaired early in the course of the disease and may sometimes precede the appearance of upper-limb apraxia. These findings also suggest that the IGT is a useful task to detect early cognitive impairments in patients with parkinsonism whose clinical symptoms are suggestive of CBD.Neurology Unit, USL of Viareggio, Italy Neuroscience Department, University of Pisa1. Mahaoatra RK , Edwards MJ , Schott JM : Corticobasal degeneration. Lancet Neurol 2004; 3:736–443Crossref, Medline, Google Scholar2. Graham NL , Bak TH , Hodges JR : Corticobasal degeneration as cognitive disorder. Mov Disord 2003; 18:1224–1232Crossref, Medline, Google Scholar3. Bechara A , Damasio AR , Damasio H , et al.: Insensitivity to future consequences following damage to human prefrontal cortex. Cognition 1994; 50:7–15Crossref, Medline, Google Scholar4. Poletti M , Frosini D , Lucetti C , et al.: Decision-making in de novo Parkinson's disease. Mov Disord 2010; 29:March, E-pub ahead of printGoogle Scholar5. De Renzi E , Lucchelli F : Ideational apraxia. Brain 1988; 111:1173–1185Crossref, Medline, Google Scholar FiguresReferencesCited byDetailsCited ByNone Volume 23Issue 2 Spring 2011Pages E29-E29 Metrics PDF download History Published online 1 April 2011 Published in print 1 April 2011