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ARTICLES: Naida L. Graham, Thomas Bak, Karalyn Patterson, and John R. Hodges Language function and dysfunction in corticobasal degeneration Neurology 2003; 61: 493-499 [Abstract] [Full text] [PDF]

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Language function and dysfunction in corticobasal degeneration

Andrew J. Larner, Mark Doran   (28 October 2003)

Reply to Larner

Naida L. Graham, Thomas H. Bak, Karalyn Patterson, and John R. Hodges   (28 October 2003)

Language function and dysfunction in corticobasal degeneration 28 October 2003
Andrew J. Larner, Walton Centre for Neurology and Neurosurgery Lower Lane, Liverpool, L9 7LJ, UK, Mark Doran Send Correspondence to journal: Re: Language function and dysfunction in corticobasal degeneration andrew.larner{at}thewaltoncentre.nhs.uk Andrew J. Larner, et al.	Dr. Graham et al studied language function in ten patients with clinically diagnosed corticobasal degeneration (CBD), one with pathological confirmation. They concluded that the language dysfunction seen in CBD forms a continuum which overlaps with cases of progressive nonfluent aphasia. [1] However, as with all studies involving clinically ascertained cases of CBD, the conclusions may be subject to pathological confounding. CBD phenocopies are well described, with diverse pathological substrates including Alzheimer’s disease, Pick’s disease, progressive supranuclear palsy, non-specific histology, motor neuron disease dementia, and Creutzfeldt-Jakob disease. [2] Furthermore, these phenocopies may be common. In one study, 6 of 13 clinically diagnosed cases of CBD had a final pathological diagnosis other than CBD. [3] It would seem that clinical phenotype reflects the neuroanatomical distribution of pathological change, rather than the precise histological nature of that change. For this reason, we have suggested that all clinically diagnosed cases be labelled "corticobasal degeneration syndrome" until their precise pathological substrate is known . [2] Identfying pathological cases of CBD premortem remains a significant clinical challenge, even using suggested diagnostic criteria [4] and clinical predictors. [5] References [1] Graham NL, Bak T, Patterson K, Hodges JR. Language function and dysfunction in corticobasal degeneration. Neurology 2003; 61: 493-499. [2] Doran M, du Plessis DG, Enevoldson TP, Fletcher NA, Ghadiali E, Larner AJ. Pathological heterogeneity of clinically diagnosed corticobasal degeneration. J Neurol Sci (in press). [3] Boeve BF, Maraganore MD, Parisi JE et al. Pathological heterogeneity in clinically diagnosed corticobasal degeneration. Neurology 1999; 53: 795-800. [4] Lang AE, Riley DE, Bergeron C. Cortical-basal ganglionic degeneration. In: Calne DB (ed.). Neurodegenerative diseases. Philadelphia: Saunders, 1994: 877-894. [5] Litvan I, Agid Y, Goetz C et al. Accuracy of the clinical diagnosis of corticobasal degeneration: a clinicopathological study. Neurology 1997; 48: 119-125.
Reply to Larner 28 October 2003
Naida L. Graham, MRC Cognition & Brain Sciences Unit 15 Chaucer Rd, Cambridge UK CB2 2EF, Thomas H. Bak, Karalyn Patterson, and John R. Hodges Send Correspondence to journal: Re: Reply to Larner naida.graham{at}mrc-cbu.cam.ac.uk Naida L. Graham, et al.	Dr. Larner expresses concern about the potential discrepancy between clinical and pathological diagnoses of corticobasal degeneration (CBD). We have addressed this question in previous studies [1] and a recent review. [2] We agree that, in an ideal world, clinical criteria would correspond with pathological diagnosis. In the thirty-five years since the original description of CBD, it has become obvious that the overlap between clinically and pathologically diagnosed cases is only partial. [3] Although we direct considerable effort to longitudinal studies of CBD patients [4] with the final goal of obtaining pathological confirmation, describing the full range of symptoms characterizing what Dr. Larner calls clinically diagnosed "corticobasal degeneration syndrome" is important. In the study he mentions, the central contribution was to demonstrate that cognitive and particularly linguistic features form a significant but often overlooked part of the clinical syndrome of CBD. Only future prospective longitudinal clinico-pathological studies will be able to determine the predictive value of these cognitive and linguistic symptoms for the pathological diagnosis of CBD. References 1. Mathuranath PS, Xuereb JH, Bak T, Hodges JR. Corticobasal ganglionic degeneration and/or frontotemporal dementia? A report of two overlap cases and review of literature. Journal of Neurology, Neurosurgery and Psychiatry 2000;68:304-312. 2. Graham NL, Bak T, Hodges JR. Corticobasal degeneration as a cognitive disorder. Movement Disorders in press. 3. Bergeron C, Pollanen MS, Weyer L, Black SE, Lang AE. Unusual clinical presentations of cortical-basal ganglionic degeneration. Annals of Neurology 1996;40:893-900. 4. Graham NL, Zeman A, Young AW, Patterson K, Hodges JR. Dyspraxia in a patient with corticobasal degeneration: The role of visual and tactile inputs to action. Journal of Neurology, Neurosurgery and Psychiatry 1999;67:334-344.