Tamotsu Kubori

Dementia in Parkinson’s disease: diffusion tensor imaging

Objective –  Dementia occurs frequently in patients with Parkinson’s disease (PD). However, the nature of the dementing process remains controversial. We evaluated various cognitive functions in patients with PD, compared fractional anisotropy (FA) values between PD patients with and without dementia.

Depression in Parkinson's disease. Diffusion tensor imaging study.

ObjectivesThe pathophysiology of depression and anxiety in Parkinson’s disease remains obscure. We aimed to compare the fractional anisotropy (FA) values of Parkinson’s disease (PD) patients with and without depression to investigate the nature of depression in PD.MethodsTwenty-eight patients were divided into two groups: those with depression and those without. Diagnosis of depression was made using the DSM-IV criteria. Patients in the two groups were matched for Hoehn Yahr stage.ResultsThere were significant reductions in FA values in the bilateral frontal ROIs possibly representing anterior cingulate bundles.ConclusionsThe anterior cingulate bundles play an important role in depression in PD, and some aspects of depression in PD have pathological processes in common with de novo depression.

Abnormal contingent negative variation in writer's cramp.

OBJECTIVE To investigate the physiological abnormality in writers cramp, a focal dystonia which specifically affects writing. METHODS We recorded brain potentials that precede hand and neck movements (contingent negative variation or CNV) in 11 patients and 11 age-matched normal subjects. A 1000 Hz tone burst (S1) was delivered to the right or left ear in random sequence, and 2 s after, a 2000 Hz tone burst (S2) was delivered to both ears simultaneously. For the response task to S2, the subjects were instructed to extend their fingers ipsilateral to the ear to which S1 was given in one experiment or to rotate the head to the side of the S1 presentation in another. All the patients had symptoms in the right hand only, and performed both tasks normally. CNV amplitudes were compared between normals and patients using unpaired t test. RESULTS They showed normal CNV for neck movement but significantly decreased CNV amplitudes for movements both in the affected and unaffected hands. CONCLUSIONS Our findings suggest that motor programming is specifically abnormal for the affected body part, including the asymptomatic contralateral limb, and that the clinical symptom may result from a deficient compensatory mechanism for abnormal motor programs or subroutines.

Impaired Visual Acuity as a Risk Factor for Visual Hallucinations in Parkinson’s Disease

Pathophysiology of hallucinations in Parkinson’s disease is poorly understood. This study investigated relationships between visual hallucinations and visual acuity. Twenty-six consecutive patients with Parkinson’s disease participated in this study. Patients were divided into two groups: patients with visual hallucinations (VH group) and those without visual hallucinations (no-VH group). Unaided and corrected eyesight was evaluated in all patients, and if frequent use of prescription glasses or contact lenses was involved, eyesight using these lenses was also measured as the patient’s own best eyesight. If a patient did not use prescription glasses or contact lenses, the patient’s own best eyesight was defined as the unaided eyesight. Multivariate regression analysis demonstrated that agonist use and best eyesight were different after the backward elimination method. Visual hallucinations were closely related not to uncorrected eyesight or unaided eyesight but to the patient’s best eyesight. It is suggested that impaired visual acuity is a risk factor for visual hallucinations.

Three-dimensional stereotactic surface projection study of freezing of gait and brain perfusion image in Parkinson's disease

Gait disturbance is a cardinal symptom in patients with Parkinsons disease. Among the gait disturbances, freezing of gait is a unique and troublesome symptom, but its mechanism is unclear. We compared brain perfusion images using three‐dimensional stereotactic surface projection analysis of N‐isopropyl‐p‐123I iodoamphetamine single photon emission computed tomography between Parkinsons disease patients with freezing of gait and those without. Twenty‐four cases (freezing of gait group) with Parkinsons disease with freezing of gait, and 31 Hoehn and Yahr stage‐matched cases (no freezing of gait group) with Parkinsons disease without freezing of gait were studied. Bilateral Brodmann area 11 perfusion of the freezing of gait group decreased significantly compared to that of the no freezing of gait group. The Brodmann area 11 may play important roles in gait, and impairment in this region may have a close relationship with freezing of gait in Parkinsons disease.

Hypoperfusion of the visual pathway in parkinsonian patients with visual hallucinations

Little is known about the developing mechanisms of visual hallucinations in Parkinsons disease. This study aimed to investigate perfusion changes in parkinsonian patients with visual hallucinations using n‐isopropyl‐p‐[123I]iodoamphetamine ([123I]IMP) single photon emission computed tomography imaging. A total of 70 consecutive patients, including 31 patients with visual hallucinations, and 39 patients without hallucinations, participated in this study. Patients with severe cognitive impairment (Mini‐Mental State Examination score < 20), nonvisual hallucinations, or confusion were excluded. We compared brain perfusion changes between the two groups. We found that hallucinatory patients had significant perfusion reductions in the bilateral inferior parietal lobule, inferior temporal gyrus, precuneus gyrus, and occipital cortex compared to nonhallucinatory patients. These results suggested that hypoperfusion of the visual pathway was closely related to visual hallucinations in Parkinsons disease.

Sympathetic disturbances increase risk of sudden cardiac arrest in sporadic ALS

BACKGROUND ALS exclusively involves motor neurons, however, accumulating evidence suggests involvement of sympathetic neurons, as in other diseases including Parkinsons disease and multiple system atrophy. In these diseases increased risk of sudden cardiac arrest is established, while that in ALS remains uncertain. METHODS The authors retrospectively studied 12 pathologically confirmed sporadic ALS patients who received no assisted ventilation. Among them, two patients died of sudden cardiac arrest. Changes in QTc interval and dispersion, indices of sympathetic activities obtainable by routine electrocardiograms, were evaluated at the early stage and the terminal stage. Pathologically, intermediolateral nucleus (IML) sympathetic neurons in the upper thoracic cord were examined. RESULTS The QTc intervals and dispersion were significantly increased at the terminal stage compared with that at the early stage (p<0.01). The numbers of IML neurons were significantly lower in ALS patients than in controls (p=0.017), and had linear inverse correlation with the rate of increases in maximum QTc interval and QTc dispersion (p=0.01, r=-0.915 and p=0.02, r=-0.884). Notably, two patients with sudden cardiac arrest showed longer QTc interval, larger QTc dispersion, and lower number of IML neurons than most of others. CONCLUSIONS Patients with ALS had reduced sympathetic activities at the terminal stage of disease, presumably due to neuronal loss in IML, which may increase risk of sudden cardiac arrest. Thus, prolonged QTc intervals and increased QTc dispersion may suggest an increased risk of sudden death in ALS, as in other neurodegenerative diseases.

Frontal Assessment Battery and Brain Perfusion Image in Parkinson’s Disease

The objective was to compare brain perfusion image using 3-dimensional stereotactic surface projection analysis of N-isopropyl-p-123I iodoamphetamine single photon emission computed tomography between Parkinson’s disease patients with a high frontal assessment battery score and those with a low frontal assessment battery score. Thirty nondemented patients with Parkinson’s disease were studied. Patients were divided into 2 groups: a high-scoring group whose frontal assessment battery score was 12 or more and a low-scoring group whose frontal assessment battery score was 11 or less. The high-scoring group included 21 patients, and the low-scoring group included 9 patients. They underwent N-isopropyl-p-123I iodoamphetamine single photon emission computed tomography, and we analyzed the data by the 3-dimensional stereotactic surface projection method. Results showed that left inferior parietal lobule and left supramarginal gyrus perfusion of the low-scoring group were significantly decreased compared with the high-scoring group. It is concluded that_patients with Parkinson’s disease may have frontal lobe dysfunction, but the decreased frontal assessment battery score may be caused not by progressed frontal lobe dysfunction but by parietal lobe dysfunction added to their preexisting frontal lobe impairment.

Wisconsin Card Sorting Test in Parkinson's disease: diffusion tensor imaging.

Introduction –  It is generally assumed that executive dysfunctions in Parkinsons disease (PD) are caused by degeneration of the basal ganglia or frontal cortex or both. However, there have been few studies investigating the relationship between executive dysfunctions and cerebral pathological change. The objective of this study was to evaluate various cognitive functions in non‐demented patients with PD, and to compare the fractional anisotropy (FA) values of PD patients with and without executive dysfunction.

Minor depression and brain perfusion images in Parkinson's disease

Depression is common in individuals with Parkinsons disease. However, the pathophysiology of depression in Parkinsons disease remains obscure. Here we compared brain perfusion images of Parkinsons disease patients with and without depression to investigate correlations between depression and brain perfusion images in Parkinsons disease. We divided 40 consecutive patients with Parkinsons disease into two groups: patients with minor depression (n = 22) and patients without depression (n = 18). We then compared brain perfusion images between the two groups. As a result, hypoperfusion of the left superior and inferior frontal gyrus was demonstrated in depressed patients. These results were partially in agreement with previous studies on de novo and parkinsonian major depression. We could not conclude on whether pathophysiological mechanisms differed between de novo depression and depression with Parkinsons disease, and between major and minor depressions.