Toshiaki Ieda

Cardiac (123)I-meta-iodobenzylguanidine (MIBG) uptake in dementia with Lewy bodies: comparison with Alzheimer's disease.

Cardiac 123I-meta-iodobenzylguanidine (MIBG) uptake was measured in 11 patients with dementia with Lewy bodies (DLB), 10 patients with Alzheimers disease (AD), and 10 age matched control subjects. The severity of cognitive impairment and duration of symptoms in patients with DLB matched that in the patients with AD. The heart/mediastinum (H/M) ratio of MIBG uptake in the patients with AD was indistinguishable from that in the control subjects. However, the H/M ratio in all patients with DLB was significantly lower than that in the patients with AD and control subjects (p<0.001). These findings indicate that local myocardial sympathetic nerves are affected in DLB and that cardiac 123I-MIBG scintigraphy may provide a means of differentiating DLB from AD.

Onset age and severity of motor impairment are associated with reduction of myocardial 123I-MIBG uptake in Parkinson's disease

Objectives: To elucidate the factors associated with severity of cardiac sympathetic nerve involvement in idiopathic Parkinson’s disease (PD). Methods:123I-metaiodobenzylguanidine uptake was examined in 88 patients with PD. The ratio of the uptake in the heart (H) to that in the mediastinum (M) (the H/M ratio) was calculated and correlated with age at onset, age at examination, and disease severity and duration. Twenty five healthy people were also examined as a control. Results: There was a mild but significant negative correlation between H/M ratio and age at onset (early, r = −0.33, p = 0.002; delayed, r = −0.34, p = 0.001) and between Hoehn and Yahr (H-Y) stage (early, r = −0.30, p = 0.006; delayed, r = −0.32, p = 0.003). There was no significant correlation between disease duration and H/M ratio. When patients with PD were classified into four subgroups on the basis of age at onset (> 62 or < 62 years) and disease severity (H-Y > III or H-Y ⩽ II), the median H/M ratio of the older and more severe group was significantly lower than that of the younger and less severe group (p = 0.005). Conclusion: This study suggests that late onset, high severity PD is associated with myocardial sympathetic dysfunction.

Clinical and physiological characteristics of autonomic failure with Parkinson's disease

We analyzed the clinical and physiological features of autonomic failure with Parkinsons disease (AF-PD) in seven patients and compared them with those of autonomic failure with multiple system atrophy (AF-MSA). In AF-PD, parkinsonism was more gradually progressive than in AF-MSA, and symptoms were responsive to L-dopa. All seven patients with AF-PD had orthostatic hypotension, postprandial hypotension, and constipation, but no urinary retention. Of these, three had hypohidrosis and five had frequent urination; five patients had subnormal plasma norepinephrine (NE) concentrations. Supersensitivity to NE infusion was observed in all patients. Head-up tilting (HUT) test resulted in no increase of plasma NE concentrations in both groups, but a significant increase of the plasma arginine vasopressin (AVP) concentrations in the patients with AF-PD. Urodynamic studies revealed that urinary bladder function was relatively well preserved in AF-PD in contrast to AF-MSA. In conclusion, there exists some clinical and physiological differences in autonomic features between AF-PD and AF-MSA, and postganglionic involvement predominates in AF-PD.

Parieto-occipital glucose hypometabolism in Parkinson's disease with autonomic failure

To investigate the characteristics of regional cerebral metabolism in a subgroup of patients with Parkinsons disease and autonomic failure, we studied seven patients with Parkinsons disease with autonomic failure (PA group), 11 patients with Parkinsons disease without apparent autonomic failure (PD group), and nine normal controls using fluoro-deoxyglucose positron emission tomography (FDG-PET). To determine differences in metabolic distribution among these groups, regional relative glucose metabolic rates (RGMR), which were normalized with cerebellar values, were calculated and age-adjusted covariance analyses were done. When compared with that of controls. RGMR in the cerebral cortex of the PA group was markedly reduced in the occipital cortex (P<0.001), inferior parietal cortex (P<0.005) and superior parietal cortex (P<0.005), but without a decrease in the sensory motor and medial temporal cortices, putamen and thalamus. In contrast, the PD group did not show significant focal hypometabolic distribution. Our findings raise the possibility that Parkinsons disease with autonomic failure may overlap with the features of dementia with Lewy bodies.

Auditory brainstem responses in patients with autonomic failure with Parkinson's disease and multiple system atrophy

Auditory brainstem responses (ABRs) were examined in six patients with autonomic failure with Parkinsons disease (AF with PD) and 10 patients with autonomic failure with multiple system atrophy (AF with MSA), all of which showed marked parkinsonian features as a principal sign. We designated the central abnormalities of ABRs as prolongation of latencies (wave III or V) and interpeak latencies (IPLs; I-III, I-V, and III-V IPL) or decreased amplitude ratios of wave III or V to those of wave I (less than 1.0). None of the patients with AF with PD showed abnormalities in ABRs. In contrast, in those with AF with MSA, the peak latencies or IPLs were prolonged in two of the 10 patients, and the amplitude ratios of wave III or V to those of wave I were decreased in other two of these patients. Moreover, both prolongation of latencies and a decreased ratio were observed in other one. Overall, five of the 10 patients with AF with MSA showed central abnormalities in ABRs. It is clinically difficult to differentiate AF with PD from AF with MSA, particularly when no cerebellar signs are apparent in AF with MSA patients. When central abnormalities of ABRs are observed in AF patients, AF with MSA should be suspected rather than AF with PD. In conclusion, ABRs provide useful information for the differential diagnosis of AF with PD and AF with MSA.