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Electronic response to: EDITORIALS Depression in Parkinson's disease Hervé Allain, Stéphane Schuck, and Nicolas Mauduit BMJ 2000; 320: 1287-1288 15 May 2000 Olfactory disorder and Parkinson’s Disease Dear Editor, Aside from motor and cognitive deficits, Parkinson patients also manifest an olfactory deficit. Decrease of olfactory function and odor aversion have been reported among the first symptoms in patients with Parkinson's disease (PD) by several authors [1-3]. A large number of clinical studies have also reported that olfactory loss in idiopathic PD is bilateral, present in hemiparkinsonism, unrelated to the stage or clinical subtype of the disease, and independent of antiparkinsonian medication.[4] [2] The intranasal chemosensory trigeminal system seemingly was neither affected by the neuronal degeneration seen in PD nor by treatment with antiparkinsonian drugs.[2]. The olfactory vector hypothesis even suggests that the causative agent for PD enters the brain via the nasal route, however the reason for olfactory dysfunction may be more subtle. It has been proposed that the initial causative event in PD may start in the rhinencephalon (olfactory brain) prior to damage in the basal ganglia.[7] Steven van Toller the impacted of olfactory loss on the quality of life and described that the inability to detect odours, anosmia, can cause profound psychological effects resulting in feelings of physical and social vulnerability and victimization. In addition, there may be unhappiness related to the loss of the ability to detect pleasurable food smells and, as a consequence, anosmics may develop problems relating to eating. These profound effects arise from a condition which can have a rapid onset and a very poor prognosis for recovery, and are largely treated with a lack of sympathy and indifference by people with normal olfactory ability. [9] The! se f indings could be the basis of the depression and by solving this problem the score of the quality of life could improve. In an animal experiment Fernandez-Ruiz et al [6] demonstrated that catecholamine replacement therapy leads not only to normal catecholamine levels, but also restored olfactory aversion. It was finally concluded from this study that catecholamine depletion of the amygdala is sufficient to produce a selective olfactory deficit, and that such a deficit can be reversed by adrenal medullary transplants. There was no human data available to us, although it would be very interessting. 1. Adler, C.H., K.A. Gwinn, and S. Newman, Olfactory function in restless legs syndrome. Mov Disord, 1998. 13(3): p. 563-5. 2. Barz, S., et al., Chemosensory event-related potentials in response to trigeminal and olfactory stimulation in idiopathic Parkinson's disease. Neurology, 1997. 49(5): p. 1424-31. 3. Doty, R.L., D.A. Deems, and S. Stellar, Olfactory dysfunction in parkinsonism: a general deficit unrelated to neurologic signs, disease stage, or disease duration. Neurology, 1988. 38(8): p.1237-44. 4. Liberini, P., et al., Olfaction in Parkinson's disease: methods of assessment and clinical relevance [In Process Citation]. J Neurol, 2000. 247(2): p. 88-96. 5. Doty, R.L., et al., Olfactory dysfunction in three neurodegenerative diseases. Geriatrics, 1991. 46 Suppl 1: p. 47-51. 6. Fernandez-Ruiz, J., et al., Adrenal medullary grafts restore olfactory deficits and catecholamine levels of 6-OHDA amygdala lesioned animals. J Neural Transplant Plast, 1993. 4(4): p. 289-97. 7. Hawkes, C.H., B.C. Shephard, and S.E. Daniel, Is Parkinson's disease a primary olfactory disorder? Qjm, 1999. 92(8): p. 473-80. 8. Levin, B.E. and H.L. Katzen, Early cognitive changes and nondementing behavioral abnormalities in Parkinson's disease. Adv Neurol, 1995. 65: p. 85-95. 9. Toller, S.V., Assessing the impact of anosmia: review of a questionnaire's findings. Chem Senses, 1999. 24(6): p. 705-12. Andreas F P Temmel, Christian Quint, Josef Toth, Senior Registrar Dept of ENT, University of Vienna [log in to unmask] BMJ 2000. janet paterson 53 now / 41 dx / 37 onset 613 256 8340 / PO Box 171 Almonte Ontario K0A 1A0 Canada visit my website "a new voice" at: http://www.geocities.com/janet313/