Copyright © 2012 Ana Contreras and Francisco Grandas. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Linked References

1. D. J. Thurman, J. A. Stevens, and J. K. Rao, “Practice parameter: assessing patients in a neurology practice for risk of falls (an evidence-based review). Report of the quality standards subcommittee of the American Academy of Neurology,” Neurology, vol. 70, no. 6, pp. 473–479, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
2. P. Gray and K. Hildebrand, “Fall risk factors in Parkinson's disease,” Journal of Neuroscience Nursing, vol. 32, no. 4, pp. 222–228, 2000. View at Scopus
3. A. Ashburn, E. Stack, R. M. Pickering, and C. D. Ward, “Predicting fallers in a community-based sample of people with Parkinson's disease,” Gerontology, vol. 47, no. 5, pp. 277–281, 2001. View at Publisher · View at Google Scholar · View at Scopus
4. Y. Balash, C. Peretz, G. Leibovich, T. Herman, J. M. Hausdorff, and N. Giladi, “Falls in outpatients with Parkinson's disease: frequency, impact and identifying factors,” Journal of Neurology, vol. 252, no. 11, pp. 1310–1315, 2005. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
5. M. A. Hely, W. G. J. Reid, M. A. Adena, G. M. Halliday, and J. G. L. Morris, “The Sydney multicenter study of Parkinson's disease: the inevitability of dementia at 20 years,” Movement Disorders, vol. 23, no. 6, pp. 837–844, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
6. R. M. Pickering, Y. A. M. Grimbergen, U. Rigney et al., “A meta-analysis of six prospective studies of falling in Parkinson's disease,” Movement Disorders, vol. 22, no. 13, pp. 1892–1900, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
7. O. Johnell, L. J. Melton, E. J. Atkinson, W. M. O'Fallon, and L. T. Kurland, “Fracture risk in patients with parkinsonism: a population based study in Olmsted County, Minnesota,” Age and Ageing, vol. 21, no. 1, pp. 32–38, 1992. View at Scopus
8. L. J. Melton III, C. L. Leibson, S. J. Achenbach et al., “Fracture risk after the diagnosis of Parkinson's disease: influence of concomitant dementia,” Movement Disorders, vol. 21, no. 9, pp. 1361–1367, 2006. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
9. P. Vestergaard, L. Rejnmark, and L. Mosekilde, “Fracture risk associated with parkinsonism and anti-Parkinson drugs,” Calcified Tissue International, vol. 81, no. 3, pp. 153–161, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
10. G. K. Wenning, G. Ebersbach, M. Verny et al., “Progression of falls in postmortem-confirmed parkinsonian disorders,” Movement Disorders, vol. 14, no. 6, pp. 947–950, 1999. View at Publisher · View at Google Scholar · View at Scopus
11. A. L. Adkin, J. S. Frank, and M. S. Jog, “Fear of falling and postural control in Parkinson's disease,” Movement Disorders, vol. 18, no. 5, pp. 496–502, 2003. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
12. B. R. Bloem, J. M. Hausdorff, J. E. Visser, and N. Giladi, “Falls and freezing of gait in Parkinson's disease: a review of two interconnected, episodic phenomena,” Movement Disorders, vol. 19, no. 8, pp. 871–884, 2004. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
13. J. A. Temlett and P. D. Thompson, “Reasons for admission to hospital for Parkinson's disease,” Internal Medicine Journal, vol. 36, no. 8, pp. 524–526, 2006. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
14. A. E. Spottke, M. Reuter, O. Machat et al., “Cost of illness and its predictors for Parkinson's disease in Germany,” PharmacoEconomics, vol. 23, no. 8, pp. 817–836, 2005. View at Publisher · View at Google Scholar · View at Scopus
15. D. R. Williams, H. C. Watt, and A. J. Lees, “Predictors of falls and fractures in bradykinetic rigid syndromes: a retrospective study,” Journal of Neurology, Neurosurgery and Psychiatry, vol. 77, no. 4, pp. 468–473, 2006. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
16. W. C. Koller, S. Glatt, B. Vetere-Overfield, and R. Hassanein, “Falls and Parkinson's disease,” Clinical Neuropharmacology, vol. 12, no. 2, pp. 98–105, 1989. View at Scopus
17. J. D. Schaafsma, N. Giladi, Y. Balash, A. L. Bartels, T. Gurevich, and J. M. Hausdorff, “Gait dynamics in Parkinson's disease: relationship to Parkinsonian features, falls and response to levodopa,” Journal of the Neurological Sciences, vol. 212, no. 1-2, pp. 47–53, 2003. View at Publisher · View at Google Scholar · View at Scopus
18. M. Matinolly, J. T. Korpelainen, R. Korpelainen, K. A. Sotaniemi, M. Virranniemi, and V. V. Myllyla, “Postural sway and falls in Parkinson's disease: a regression approach,” Movement Disorders, vol. 22, no. 13, pp. 1927–1935, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
19. A. Frenklach, S. Louie, M. M. Koop, and H. Bronte-Stewart, “Excessive postural sway and the risk of falls at different stages of Parkinson's disease,” Movement Disorders, vol. 24, no. 3, pp. 377–385, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
20. P. Valkovic, H. Brozova, K. Botzel, E. Ruzicka, and J. Benetin, “Push and release test predicts better Parkinson fallers and nonfallers than the pull test: comparison in OFF and ON medication states,” Movement Disorders, vol. 23, no. 10, pp. 1453–1457, 2008. View at Publisher · View at Google Scholar · View at PubMed
21. M. Morris, R. Iansek, F. Smithson, and F. Huxham, “Postural instability in Parkinson's disease: a comparison with and without a concurrent task,” Gait and Posture, vol. 12, no. 3, pp. 205–216, 2000. View at Publisher · View at Google Scholar
22. M. R. Landers, A. Backlund, J. Davenport, J. Fortune, S. Schuerman, and P. Altenburger, “Postural instability in idiopathic parkinson's disease: discriminating fallers from nonfallers based on standardized clinical measures,” Journal of Neurologic Physical Therapy, vol. 32, no. 2, pp. 56–61, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
23. M. D. Latt, S. R. Lord, J. G. L. Morris, and V. S. C. Fung, “Clinical and physiological assessments for elucidating falls risk in Parkinson's disease,” Movement Disorders, vol. 24, no. 9, pp. 1280–1289, 2009. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
24. K. Robinson, A. Dennison, D. Roalf et al., “Falling risk factors in Parkinson's disease,” NeuroRehabilitation, vol. 20, no. 3, pp. 169–182, 2005. View at Publisher · View at Google Scholar · View at Scopus
25. B. R. Bloem, Y. A. Grimbergen, M. Cramer, M. Willemsen, and A. H. Wwinderman, “Prospective assessment of falls in Parkinson's disease,” Journal of Neurology, vol. 248, no. 11, pp. 950–958, 2001. View at Publisher · View at Google Scholar · View at Scopus
26. B. H. Wood, J. A. Bilclough, A. Bowron, and R. W. Walker, “Incidence and prediction of falls in Parkinson's disease: a prospective multidisciplinary study,” Journal of Neurology Neurosurgery & Psychiatry, vol. 72, no. 6, pp. 721–725, 2002. View at Publisher · View at Google Scholar
27. G. K. Kerr, C. J. Worringham, M. H. Cole, P. F. Lacherez, J. M. Wood, and P. A. Silburn, “Predictors of future falls in Parkinson disease,” Neurology, vol. 75, no. 2, pp. 116–124, 2010. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
28. A. J. Hughes, Y. Ben-Shlomo, S. E. Daniel, and A. J. Lees, “What features improve the accuracy of clinical diagnosis in Parkinson's disease: a clinicopathologic study,” Neurology, vol. 42, no. 6, pp. 1142–1146, 1992. View at Scopus
29. M. E. Tinetti, M. Speechley, and S. F. Ginter, “Risk factors for falls among elderly persons living in the community,” The New England Journal of Medicine, vol. 319, no. 26, pp. 1701–1707, 1988. View at Scopus
30. M. E. Tinetti and C. S. Williams, “Falls, injuries due to falls, and the risk of admission to a nursing home,” The New England Journal of Medicine, vol. 337, no. 18, pp. 1279–1284, 1997. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
31. K. R. Chaudhuri, P. Martinez-Martin, R. G. Brown et al., “The metric properties of a novel non-motor symptoms scale for Parkinson's disease: results from an international pilot study,” Movement Disorders, vol. 22, no. 13, pp. 1901–1911, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
32. S. Fahn and R. L. Elton, “Unified Parkinson’s disease rating scale,” in Recent Developments in Parkinson’s Disease, S. Fahn, C. D. Marsden, M. Goldstein, and D. B. Calne, Eds., pp. 153–163, Macmillan Healthcare Information, Florham Park, NJ, USA, 1987.
33. R. S. Schwab, A. C. England, and E. Peterson, “Akinesia in Parkinson’s disease,” Neurology, vol. 9, pp. 65–72, 1959.
34. M. M. Hoehn and M. D. Yahr, “Parkinsonism: onset, progression and mortality,” Neurology, vol. 17, no. 5, pp. 427–442, 1967. View at Scopus
35. M. F. Folstein, S. E. Folstein, and P. R. McHugh, “‘Mini mental state’: a practical method for grading the cognitive state of patients for the clinician,” Journal of Psychiatric Research, vol. 12, no. 3, pp. 189–198, 1975. View at Publisher · View at Google Scholar · View at Scopus
36. M. E. Tinetti, “Performance-orientated assessment of mobility problems in elderly patients,” Journal of the American Geriatrics Society, vol. 34, no. 2, pp. 119–126, 1986. View at Scopus
37. N. Giladi, H. Shabtai, E. S. Simon, S. Biran, J. Tal, and A. D. Korczyn, “Construction of freezing of gait questionnaire for patients with parkinsonism,” Parkinsonism and Related Disorders, vol. 6, no. 3, pp. 165–170, 2000. View at Publisher · View at Google Scholar · View at Scopus
38. D. Podsiadlo and S. Richardson, “The timed “Up & Go”: a test of basic functional mobility for frail elderly persons,” Journal of the American Geriatrics Society, vol. 39, no. 2, pp. 142–148, 1991. View at Scopus
39. T. Boonstra, H. Van der Kooij, M. Munneke, and B. R. Bloem, “Gait disorders and balance disturbances in Parkinson's disease. Clinical update and pathophysiology,” Current Opinion in Neurology, vol. 21, no. 4, pp. 461–471, 2008. View at Scopus
40. D. A. Kegelmeyer, A. D. Kloos, K. M. Thomas, and S. K. Kostyk, “Reliability and validity of the Tinetti mobility test for individuals with Parkinson disease,” Physical Therapy, vol. 87, no. 10, pp. 1369–1378, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
41. L. M. Shulman, A. L. Gruber-Baldini, K. E. Anderson et al., “The evolution of disability in Parkinson’s disease,” Movement Disorders, vol. 23, no. 6, pp. 790–796, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
42. F. B. Horak, D. Dimitrova, and J. G. Nutt, “Direction-specific postural instability in subjects with Parkinson's disease,” Experimental Neurology, vol. 193, no. 2, pp. 504–521, 2005. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
43. W. G. Wright, V. S. Gurfinkel, L. A. King, J. G. Nutt, P. J. Cordo, and F. B. Horak, “Axial kinesthesia is impaired in Parkinson's disease: effects of levodopa,” Experimental Neurology, vol. 225, no. 1, pp. 202–209, 2010. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
44. A. H. Rajput, A. Voll, M. L. Rajput, C. A. Robinson, and A. Rajput, “Course in parkinson disease subtypes: a 39-year clinicopathologic study,” Neurology, vol. 73, no. 3, pp. 206–212, 2009. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
45. G. Yogev-Seligmann, J. M. Hausdorff, and N. Giladi, “The role of executive function and attention in gait,” Movement Disorders, vol. 23, no. 3, pp. 329–342, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
46. J. D. Holmes, M. E. Jenkins, A. M. Johnson, S. G. Adams, and S. J. Spaulding, “Dual-task interference: the effects of verbal cognitive tasks on upright postural instability in Parkinson’s disease,” Parkinson's Disease, vol. 2010, Article ID 696492, 5 pages, 2010. View at Publisher · View at Google Scholar · View at PubMed
47. P. A. Kempster, S. S. O'Sullivan, J. L. Holton, T. Revesz, and A. J. Lees, “Relationships between age and late progression of Parkinson's disease: a clinico-pathological study,” Brain, vol. 133, no. 6, pp. 1755–1762, 2010. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
48. S. R. Cummings, M. C. Nevitt, and S. Kidd, “Forgetting falls. The limited accuracy of recall of falls in the elderly,” Journal of the American Geriatrics Society, vol. 36, no. 7, pp. 613–616, 1988. View at Scopus
49. C. Sherrington, J. C. Whitney, S. R. Lord, R. D. Herbert, R. G. Cumming, and J. C. T. Close, “Effective exercise for the prevention of falls—a systematic review and meta-analysis,” Journal of the American Geriatrics Society, vol. 56, no. 12, pp. 2234–2243, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
50. A. Ashburn, L. Fazakarley, C. A. Ballinger, R. Pickering, L. D. McLellan, and C. A. Fitton, “A randomised controlled trial of a home based exercise programme to reduce the risk of falling among people with Parkinson's disease,” Journal of Neurology, Neurosurgery and Psychiatry, vol. 78, no. 7, pp. 678–684, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
51. A. Nieuwboer, G. Kwakkel, L. Rochester et al., “Cueing training in the home improves gait-related mobility in Parkinson's disease: the RESCUE trial,” Journal of Neurology, Neurosurgery and Psychiatry, vol. 78, no. 2, pp. 134–140, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
52. K. A. Chung, B. M. Lobb, J. G. Nutt, and F. B. Horak, “Effects of a central cholinesterase inhibitor on reducing falls in Parkinson disease,” Neurology, vol. 75, no. 14, pp. 1263–1269, 2010. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
53. M. Ganesan, P. K. Pal, A. Gupta, and T. Sathyaprabha, “Dynamic posturography in evaluation of balance in patients of Parkinson's disease with normal pull test: concept of a diagonal pull test,” Parkinsonism and Related Disorders, vol. 16, no. 9, pp. 595–599, 2010. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
54. A. L. Adkin, B. R. Bloem, and J. H. J. Allum, “Trunk sway measurements during stance and gait tasks in Parkinson's disease,” Gait and Posture, vol. 22, no. 3, pp. 240–249, 2005. View at Publisher · View at Google Scholar · View at Scopus