Atypical parkinsonism in the French West Indies

Abstract

The criteria Dominique Caparros-Lefebvre, Alexis Elbaz, and the Caribbean Parkinsonism Study Group (July 24, p 281)1Caparros-Lefebvre D Elbaz A the Caribbean Parkinsonism Study GroupPossible relation of atypical parkinsonism in the French West Indies with consumption of tropical plants: a case-control study.Lancet. 1999; 354: 281-286Summary Full Text Full Text PDF PubMed Scopus (197) Google Scholar used to make a diagnosis of progressive supranuclear palsy were not, contrary to their claims, the consensus criteria delineated by the National Institutes of Neurological Disorders and Stroke (NINDS) and Society for Progressive Supranuclear Palsy (SPSP). Instead, they used the nine-item inclusion criteria proposed by Blin and Colleagues.2Blin J Baron JC Dubois B et al.Positron emission tomography study in progressive supranuclear palsy. Brain hypometabolic pattern and clinicometabolic correlations.Arch Neurol. 1990; 47: 747-752Crossref PubMed Scopus (181) Google Scholar The NINDS-SPSP research criteria for the diagnosis of progressive supranuclear palsy have different degrees of certainty. The probable research criteria include the onset, after age 40, of progressive postural instability with falls during the first year of symptom-onset, supranuclear vertical gaze palsy, and no evidence of other diseases that could explain these features, as indicated by mandatory exclusionary criteria (eg, prominent, early unexplained dysautonomia manifested by striking hypotension, and urinary disturbances).3Litvan I Agid Y Calne D et al.Clinical research criteria for the diagnosis of progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome): report of the NINDS-SPSP international workshop.Neurology. 1996; 47: 1-9Crossref PubMed Scopus (2054) Google Scholar The criteria do not require specific disease duration, presence of frontal-lobe type features, pseudobulbar palsy, or predominance of axial rigidity, although some of these features are usually present when the criteria are met. The relevance of the distinction is not only to compare published studies, but to appropriately classify the population described. The sensitivity, specificity, and positive-predictive value of the different criteria differ.3Litvan I Agid Y Calne D et al.Clinical research criteria for the diagnosis of progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome): report of the NINDS-SPSP international workshop.Neurology. 1996; 47: 1-9Crossref PubMed Scopus (2054) Google Scholar, 4Litvan I Agid Y Jankovic J et al.Accuracy of clinical criteria for the diagnosis of progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome).Neurology. 1996; 46: 922-930Crossref PubMed Scopus (319) Google Scholar For example, the sensitivity (50%) of the probable NINDS-SPSP criteria for progressive supranuclear palsy and the sensitivity of the probable Blin2Blin J Baron JC Dubois B et al.Positron emission tomography study in progressive supranuclear palsy. Brain hypometabolic pattern and clinicometabolic correlations.Arch Neurol. 1990; 47: 747-752Crossref PubMed Scopus (181) Google Scholar criteria (23%) are not the same.3Litvan I Agid Y Calne D et al.Clinical research criteria for the diagnosis of progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome): report of the NINDS-SPSP international workshop.Neurology. 1996; 47: 1-9Crossref PubMed Scopus (2054) Google Scholar The differences are even greater if we compare the possible criteria (NINDS-SPSP criteria sensitivity 83%, specificity 93%, and positive-predictive value 83%; Blin2Blin J Baron JC Dubois B et al.Positron emission tomography study in progressive supranuclear palsy. Brain hypometabolic pattern and clinicometabolic correlations.Arch Neurol. 1990; 47: 747-752Crossref PubMed Scopus (181) Google Scholar criteria sensitivity 63%, specificity 85%, and positive-predictive value 63%).3Litvan I Agid Y Calne D et al.Clinical research criteria for the diagnosis of progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome): report of the NINDS-SPSP international workshop.Neurology. 1996; 47: 1-9Crossref PubMed Scopus (2054) Google Scholar With the less strict criteria for the diagnosis of progressive supranuclear palsy, Caparros-Lefebvre and colleagues seem to have included many patients in their study with features that have rarely been described in patients with pathologically confirmed progressive supranuclear palsy (eg, signs of motor neuron disease, postural hypotension, and rubral tremor). They state that eight of their patients did not have gaze palsy, but in the table only six patients with progressive supranuclear palsy are listed as lacking supranuclear gaze palsy. My impression is that many of the patients reported by Caparros-Lefebvre and colleagues more closely resemble patients with lytico and bodig disease of Guam (previously amyotrophic lateral sclerosis-parkin-sonism-dementia complex of Guam). Atypical parkinsonism in the French West IndiesAuthors' reply Full-Text PDF