Unclassifiable parkinsonism in two European tertiary referral centres for movement disorders

Parkinson's disease

Parkinson's disease is a common progressive bradykinetic disorder that can be accurately diagnosed. It is characterised by the presence of severe pars-compacta nigral-cell loss, and accumulation of aggregated alpha-synuclein in specific brain stem, spinal cord, and cortical regions. The main known risk factor is age. Susceptibility genes including alpha-synuclein, leucine rich repeat kinase 2 (LRRK-2), and glucocerebrosidase (GBA) have shown that genetic predisposition is another important causal factor. Dopamine replacement therapy considerably reduces motor handicap, and effective treatment of associated depression, pain, constipation, and nocturnal difficulties can improve quality of life. Embryonic stem cells and gene therapy are promising research therapeutic approaches.

Prevalence of movement disorders in an elderly nursing home population

We studied the prevalence of movement disorders in a large nursing home population (397 patients, mean age 86 years) in New York City. Patients were first evaluated by specially trained research coordinators and final clinical diagnoses were confirmed by a movement disorder specialist. A movement disorder was identified in 21% of patients (83/397). The most frequent movement disorders were essential tremor (ET) (8.8%) and parkinsonism (7.1%). Only half of those admitted with a diagnosis of parkinsonism were confirmed in their diagnosis by the movement disorder specialists. Three percent of patients exhibited drug-induced tremor, 1.3% had dystonia, 0.5% had myoclonus and 0.3% had generalized dyskinesias. Overall, our findings underline the high frequency of movement disorders in a nursing home population. The discrepancy between our findings and the prevalence rates for parkinsonism reported on the initial transfer diagnosis emphasizes the difficulty of accurate diagnosis of movement disorders and in particular parkinsonism.

Clinical differential diagnosis of parkinsonism

Several clinical diagnostic criteria are available for differentiating Parkinson’s disease from the various forms of parkinsonism, but most clinical features have inadequate sensitivity and positive predictive value in the differential diagnosis of these conditions. Although a diagnosis of Parkinson’s disease can be a simple clinical exercise in typical patients with a positive response to dopaminergic treatment, the differential diagnosis versus other parkinsonian disorders can be challenging in some cases, particularly early in the disease. In this paper we have reviewed the motor and nonmotor clinical features that are helpful in the differential diagnosis of the most common forms of parkinsonism. A correct diagnosis in a parkinsonian patient is not simply an academic exercise, but it is crucial for planning any possible therapeutical intervention.

Primary lateral sclerosis mimicking atypical parkinsonism

Primary lateral sclerosis (PLS), the upper motor neurone variant of motor neurone disease, is characterized by progressive spinal or bulbar spasticity with minimal motor weakness. Rarely, PLS may present with clinical features resembling parkinsonism resulting in occasional misdiagnosis as one of the atypical parkinsonian syndromes. Here we describe five patients initially referred with a diagnosis of levodopa-unresponsive atypical parkinsonism (n = 4) or primary progressive multiple sclerosis (n = 1), but subsequently found to have features consistent with PLS instead. Onset age varied from 49 to 67 years. Unilateral limb slowness or clumsiness was the initial complaint in four, and bulbar symptoms in one. Repeated finger/foot tapping was slow in all five, but without fatiguing or decrement. Spasticity with hyperreflexia, exaggerated jaw jerk and extensor plantar responses were eventually seen in all patients. Anterior horn cell involvement developed in three cases. Early gait disturbances resulting in falls were seen in all patients and none of them responded to dopaminergic medications. Two patients underwent dopamine transporter (DaT) SPECT scanning with normal results. Other features included emotional lability (n = 5) and cognitive impairment involving frontal subcortical systems (n = 1). In conclusion, these cases represent a subgroup of PLS patients in whom pyramidal slowness may be mistaken for akinesia, and spasticity misconstrued as rigidity, leading to an erroneous diagnosis of atypical parkinsonism. However, the absence of fatiguing and decrement on repeated finger/foot tapping should help to distinguish these patients from the true atypical parkinsonian syndromes.

Identifying incident cases of parkinsonism among veterans using a tertiary medical center

To better understand the impact of incident Parkinson's disease (PD) on the Veteran's Health Administration (VHA) and to develop methods applicable to future epidemiological research, we performed a medical record review study at a tertiary referral VHA medical center. Searching the local data base, we identified 782 veterans with diagnostic codes for PD or secondary parkinsonism (SP) between 1998 and 2000. Based on structured medical record review, a movement disorders specialist confirmed diagnoses for incident parkinsonism cases. Among the 782, 191 incident parkinsonism cases were identified (100 PD, 75 SP, and 16 Parkinson's Plus). Incident PD cases were older at diagnosis (74.5 vs. 70.4 yr; P < 0.05) and more likely to be white (81% vs. 62; P < 0.07) than incident SP cases. Diagnostic codes were insufficient to distinguish between incident PD and SP (positive predictive value, 57% and 39%, respectively), and VHA sources failed to identify 21% of confirmed deaths among the incident PD cohort by November 2004. Although the large number of incident cases identified suggests PD is an important cause of disability among elderly VHA users, observed limitations of VHA sources for identifying incident PD cases and determining their vital status should be considered when designing future studies.

Morphological substrates of parkinsonism with and without dementia: a retrospective clinico-pathological study

A retrospective study of a 50-year autopsy series of 900 patients with the clinical diagnosis of parkinsonism (31.2% with dementia) revealed pure Lewy body disease (LBD) in 84.9%, but only 44.7% with idiopathic Parkinson disease (PD); 16% were associated with cerebrovascular lesions, 14.8% with Alzheimer pathology; 8.9% were classified dementia with Lewy bodies (DLB), 9.4% showed other degenerative disorders, and 5.6% other/ secondary parkinsonian syndromes. The frequency of LBD during different periods was fairly stable, with increase of DLB and PD plus Alzheimer changes, but decrease of associated cerebrovascular lesions during the last decades. Using variable clinical diagnostic criteria not only by specified neurologists, the misdiagnosis rate ranged from 11.5 to 23% and was similar to that in most previous clinico-pathological studies. The majority of cases with false clinical diagnosis of PD had a final pathological diagnosis of DLB with or without Alzheimer lesions. A postmortem series of 330 elderly patients clinically diagnosed as parkinsonism with (37.6%) and without dementia showed that IPD, Braak stages 3-5 were rarely associated with cognitive impairment, which was frequently seen in IPD with associated Alzheimer pathology (35.5%), DLB (33.9%), and in Alzheimer disease (AD) or mixed dementia (17%), whereas it almost never was associated with minor cerebrovascular lesions. Clinico-pathological studies in DBL, demented and nondemented PD, and AD cases showed a negative relation between cognitive impairment and Alzheimer changes, suggesting that these either alone or in combination with cortical Lewy body pathologies are major causes of cognitive dysfunction. Further prospective clinico-pathological studies are needed to validate the currently used clinical criteria for PD, to increase the diagnostic accuracy until effective biomarkers are available, and to clarify the impact of structural and functional changes on cognitive function in parkinsonism as an ultimate goal of early disease detection and effective treatment.

Two-year follow-up in 150 consecutive cases with normal dopamine transporter imaging

BACKGROUND AND AIMS

Functional pre-synaptic dopamine brain imaging is generally abnormal when parkinsonism is degenerative (such as in idiopathic Parkinson's disease) and normal in patients with non-degenerative movement disorder (such as essential tremor). However, some patients diagnosed as early Parkinson's disease have normal presynaptic dopamine imaging. Follow-up of patients with normal imaging should help determine whether such patients truly have degenerative parkinsonism (and therefore represent false negative imaging results), or emerge as cases of non-degenerative parkinsonism (and therefore represent initial clinical over-diagnosis of Parkinson's disease).

METHODS AND RESULTS

One hundred and fifty cases with normal I-FP-CIT SPECT undertaken during routine care over a 3-year period were reviewed 2.4 years (interquartile range, 2.2-3.1 years) after SPECT. Diagnosis after follow-up was non-degenerative parkinsonism or tremor in 146 (97%), who did not progress clinically, and degenerative parkinsonism in four (3%), in whom clinical progression was noted. Anti-Parkinson therapy was used in 36, and withdrawn in 27 with no deterioration in 25. Patients strictly fulfilling Brain Bank criteria (part 1) were more likely to undergo a trial of anti-Parkinson therapy (P < 0.05) but were no more likely to maintain or respond to anti-Parkinson therapy than those not fulfilling criteria.

CONCLUSION

The clinical profile and therapy response during follow-up of patients with normal presynaptic dopamine imaging supports the diagnosis of a non-degenerative movement disorder in nearly all cases.

Ten steps to identify atypical parkinsonism

Credibility of the 10‐step test in atypical parkinsonism

Successful antiparkinsonian medication withdrawal in patients with Parkinsonism and normal FP-CIT SPECT

Between 4% and 14% of patients diagnosed with Parkinson's disease and entering clinical trials have normal presynaptic dopaminergic imaging. The effects of antiparkinsonian therapy have varied in these studies, and the consequences of stopping treatment are not reported. We present 11 patients who initially fulfilled diagnostic criteria and were treated for Parkinson's disease but in whom emerging diagnostic doubts led to antiparkinsonian therapy withdrawal, which was achieved without deterioration. Such cases represent a nondegenerative form of Parkinsonism, which does not benefit from dopaminergic therapy. Prospective vigilance regarding this category is of importance in clinical practice and clinical trials.

Atypical unclassifiable parkinsonism on Guadeloupe: An environmental toxic hypothesis

We characterize the clinical features of Parkinson's syndrome on Guadeloupe and describe possible environmental causes. Consecutive patients who were referred to the University Hospital at Pointe a Pitre with parkinsonism from September 1996 to May 2002 were included. All cases were examined in a standardized manner by a neurologist with a special interest in movement disorders and independently by 3 external movement disorders specialists, using standard operational clinical diagnostic criteria. The subjects were 265 patients with Parkinson's syndrome living on Guadeloupe, four fifths of whom had been referred by primary care physicians and one fifth by neurologists. The levodopa response was assessed after a minimum period of 1 month of continuous treatment. All patients had brain computed tomography or brain magnetic resonance imaging scans and detailed neuropsychological examinations. Of 265 patients, only 66 were classified as Parkinson's disease, whereas 58 fulfilled the National Institute of Neurological Disorders and Stroke (NINDS) and Society for Progressive Supranuclear Palsy (SPSP) criteria for progressive supranuclear palsy, 100 had unclassifiable parkinsonism, characterized by dopa-unresponsiveness, marked axial rigidity, relative symmetry of parkinsonian features, early dysarthria, and frontolimbic cognitive impairment. Within this group, early postural instability, dysarthria, a frontal behavior disorder, cortical or subcortical atrophy, pyramidal signs, axial rigidity, and family history of neurodegenerative disorders were associated with poorer prognosis. A very large number of unclassifiable cases of atypical parkinsonism that do not fulfill operational criteria for Parkinson's disease or other defined motor neurodegenerations has been observed on Guadeloupe. Most patients closely resemble descriptions of bodig from Guam. In both geographic isolates, an environmental cause has been discussed. Annonaceae fruits and herbal teas are consumed on both islands. These plants contain several neurotoxins, particularly acetogenins, which induce dopaminergic neuron loss in animals. Neuronal death involves cholinergic and dopaminergic cells of the substantia nigra and GABAergic neurons of the striatum, associated with microglial proliferation. The development of atypical parkinsonism in Guadeloupe and probably elsewhere, could result from synergistic toxicity, but acetogenins are probably the most potent neurotoxin, acting as mitochondrial complex I inhibitor.