Co-Planar Stereotaxic Atlas of the Human Brain—3-Dimensional Proportional System: An Approach to Cerebral Imaging, J. Talairach, P. Tournoux. Georg Thieme Verlag, New York (1988), 122 pp., 130 figs. DM 268

Dementia has been increasingly more recognized to be a common feature in patients with Parkinson's disease (PD), especially in old age. Specific criteria for the clinical diagnosis of dementia associated with PD (PD-D), however, have been lacking. A Task Force, organized by the Movement Disorder Study, was charged with the development of clinical diagnostic criteria for PD-D. The Task Force members were assigned to sub-committees and performed a systematic review of the literature, based on pre-defined selection criteria, in order to identify the epidemiological, clinical, auxillary, and pathological features of PD-D. Clinical diagnostic criteria were then developed based on these findings and group consensus. The incidence of dementia in PD is increased up to six times, point-prevelance is close to 30%, older age and akinetic-rigid form are associated with higher risk. PD-D is characterized by impairment in attention, memory, executive and visuo-spatial functions, behavioral symptoms such as affective changes, hallucinations, and apathy are frequent. There are no specific ancillary investigations for the diagnosis; the main pathological correlate is Lewy body-type degeneration in cerebral cortex and limbic structures. Based on the characteristic features associated with this condition, clinical diagnostic criteria for probable and possible PD-D are proposed.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/mds.21507

Clinical diagnostic criteria for dementia associated with Parkinson's disease.

Structural imaging based on magnetic resonance is an integral part of the clinical assessment of patients with suspected Alzheimer dementia. Prospective data on the natural history of change in structural markers from preclinical to overt stages of Alzheimer disease are radically changing how the disease is conceptualized, and will influence its future diagnosis and treatment. Atrophy of medial temporal structures is now considered to be a valid diagnostic marker at the mild cognitive impairment stage. Structural imaging is also included in diagnostic criteria for the most prevalent non-Alzheimer dementias, reflecting its value in differential diagnosis. In addition, rates of whole-brain and hippocampal atrophy are sensitive markers of neurodegeneration, and are increasingly used as outcome measures in trials of potentially disease-modifying therapies. Large multicenter studies are currently investigating the value of other imaging and nonimaging markers as adjuncts to clinical assessment in diagnosis and monitoring of progression. The utility of structural imaging and other markers will be increased by standardization of acquisition and analysis methods, and by development of robust algorithms for automated assessment.

http://users.loni.usc.edu/~thompson/PDF/FrisoniNRN-09.pdf

The clinical use of structural MRI in Alzheimer disease

The present study used pleasant and unpleasant music to evoke emotion and functional magnetic resonance imaging (fMRI) to determine neural correlates of emotion processing. Unpleasant (permanently dissonant) music contrasted with pleasant (consonant) music showed activations of amygdala, hippocampus, parahippocampal gyrus, and temporal poles. These structures have previously been implicated in the emotional processing of stimuli with (negative) emotional valence; the present data show that a cerebral network comprising these structures can be activated during the perception of auditory (musical) information. Pleasant (contrasted to unpleasant) music showed activations of the inferior frontal gyrus (IFG, inferior Brodmann's area (BA) 44, BA 45, and BA 46), the anterior superior insula, the ventral striatum, Heschl's gyrus, and the Rolandic operculum. IFG activations appear to reflect processes of music-syntactic analysis and working memory operations. Activations of Rolandic opercular areas possibly reflect the activation of mirror-function mechanisms during the perception of the pleasant tunes. Rolandic operculum, anterior superior insula, and ventral striatum may form a motor-related circuitry that serves the formation of (premotor) representations for vocal sound production during the perception of pleasant auditory information. In all of the mentioned structures, except the hippocampus, activations increased over time during the presentation of the musical stimuli, indicating that the effects of emotion processing have temporal dynamics; the temporal dynamics of emotion have so far mainly been neglected in the functional imaging literature.

/pdf/investigating-emotion-with-music-an-fmri-study-4sfjq6btlc.pdf

Investigating emotion with music: an fMRI study.

Neural modeling and imaging of the cortical interactions underlying syllable production.

We investigated the disease progression and survival in 230 Japanese patients with multiple system atrophy (MSA; 131 men, 99 women; 208 probable MSA, 22 definite; mean age at onset, 55.4 years). Cerebellar dysfunction (multiple system atrophy-cerebellar; MSA-C) predominated in 155 patients, and parkinsonism (multiple system atrophy-parkinsonian; MSA-P) in 75. The median time from initial symptom to combined motor and autonomic dysfunction was 2 years (range 1-10). Median intervals from onset to aid-requiring walking, confinement to a wheelchair, a bedridden state and death were 3, 5, 8 and 9 years, respectively. Patients manifesting combined motor and autonomic involvement within 3 years of onset had a significantly increased risk of not only developing advanced disease stage but also shorter survival (P < 0.01). MSA-P patients had more rapid functional deterioration than MSA-C patients (aid-requiring walking, P = 0.03; confinement to a wheelchair, P < 0.01; bedridden state, P < 0.01), but showed similar survival. Onset in older individuals showed increased risk of confinement to a wheelchair (P < 0.05), bedridden state (P = 0.03) and death (P < 0.01). Patients initially complaining of motor symptoms had accelerated risk of aid-requiring walking (P < 0.01) and confinement to a wheelchair (P < 0.01) compared with those initially complaining of autonomic symptoms, while the time until confinement to a bedridden state and survival were no worse. Gender was not associated with differences in worsening of function or survival. On MRI, a hyperintense rim at the lateral edge of the dorsolateral putamen was seen in 34.5% of cases, and a 'hot cross bun' sign in the pontine basis (PB) in 63.3%. These putaminal and pontine abnormalities became more prominent as MSA-P and MSA-C features advanced. The atrophy of the cerebellar vermis and PB showed a significant correlation particularly with the interval following the appearance of cerebellar symptoms in MSA-C (r = 0.71, P < 0.01, r = 0.76 and P < 0.01, respectively), but the relationship between atrophy and functional status was highly variable among the individuals, suggesting that other factors influenced the functional deterioration. Atrophy of the corpus callosum was seen in a subpopulation of MSA, suggesting hemispheric involvement in a subgroup of MSA patients. The present study suggested that many factors are involved in the progression of MSA but, most importantly, the interval from initial symptom to combined motor and autonomic dysfunction can predict functional deterioration and survival in MSA.

/pdf/progression-and-prognosis-in-multiple-system-atrophy-an-58npx878a2.pdf

Progression and prognosis in multiple system atrophy: an analysis of 230 Japanese patients.

Somatosensory Homunculus as Drawn by MEG

We investigated the relative differences in dopaminergic function through the whole brain in patients with Parkinson's disease without dementia (PD) and with dementia (PDD) using 6-[18F]fluoro-L-dopa (18F-dopa) PET and a voxel-by-voxel analysis. The 10 PD and 10 PDD patients were equivalently disabled, having mean scores of 3.2 +/- 0.6 and 3.2 +/- 0.7, respectively, on the Hoehn and Yahr rating scale. 18F-dopa influx constant (Ki) images of those patients and 15 normal age-matched subjects were transformed into standard stereotactic space. The significant differences between the groups (expressed in mean regional Ki values) were localized with statistical parametric mapping (SPM) on a voxel-by-voxel basis. Compared with the normal group, SPM localized declines of the 18F-dopa Ki bilaterally in the putamen, the right caudate nucleus and the left ventral midbrain for the PD group (P < 0.01, corrected). Compared with the normal group, the PDD group showed reduced 18F-dopa Ki bilaterally in the striatum, midbrain and anterior cingulate area (P < 0.01, corrected). A relative difference in 18F-dopa uptake between PD and PDD was the bilateral decline in the anterior cingulate area and ventral striatum and in the right caudate nucleus in the PDD group (P < 0.001, corrected). Accordingly, we conclude that dementia in PD is associated with impaired mesolimbic and caudate dopaminergic function.

/pdf/striatal-and-extrastriatal-dysfunction-in-parkinson-s-5aw7gvl076.pdf

Striatal and extrastriatal dysfunction in Parkinson's disease with dementia: A 6-[18F]fluoro-L-dopa PET study

Objective: The purpose of this study was to analyse changes in regional cerebral blood flow (rCBF) in Parkinson's disease (PD) without dementia. 

Methods: Twenty eight non-demented patients with PD and 17 age matched normal subjects underwent single photon emission computed tomography with N-isopropyl-p-[123I]iodoamphetamine to measure rCBF. The statistical parametric mapping 96 programme was used for statistical analysis. 

Results: The PD patients showed significantly reduced rCBF in the bilateral occipital and posterior parietal cortices (p<0.01, corrected for multiple comparison p<0.05), when compared with the control subjects. There was a strong positive correlation between the score of Raven's coloured progressive matrices (RCPM) and the rCBF in the right visual association area (p<0.01, corrected for multiple comparison p<0.05) among the PD patients. 

Conclusions: This study showed occipital and posterior parietal hypoperfusion in PD patients without dementia. Furthermore, it was demonstrated that occipital hypoperfusion is likely to underlie impairment of visual cognition according to the RCPM test, which is not related to motor impairment.

https://jnnp.bmj.com/content/jnnp/74/4/419.full.pdf

Occipital hypoperfusion in Parkinson’s disease without dementia: correlation to impaired cortical visual processing

To determine the characteristics of cerebral glucose metabolism in Parkinson's disease patients with visual hallucinations, group comparison studies using [18F]fluorodeoxyglucose positron emission tomography were performed. Nondemented Parkinson's disease patients in advanced stages were classified into two groups: (1) patients without visual hallucinations; (2) patients with visual hallucinations. Compared to patients without hallucinations, the relative regional cerebral glucose metabolic rate was greater in the frontal areas in patients with visual hallucinations, and the increase reached a significant level in the left superior frontal gyrus. Relative frontal hypermetabolism may be a feature of Parkinson's disease patients with visual hallucinations.

Yuji Abe

Papers

Progression and prognosis in multiple system atrophy: an analysis of 230 Japanese patients.

Somatosensory Homunculus as Drawn by MEG

Striatal and extrastriatal dysfunction in Parkinson's disease with dementia: A 6-[18F]fluoro-L-dopa PET study

Occipital hypoperfusion in Parkinson’s disease without dementia: correlation to impaired cortical visual processing

Visual hallucination in Parkinson's disease with FDG PET