The course of brain atrophy in Parkinson's disease

Axial Signs and Magnetic Resonance Imaging Correlates in Parkinson's Disease

Background:

Age-related brain changes may contribute to axial features in Parkinson's disease (PD).

Objectives:

To determine if ventricular volume and white matter high signal changes (WMC) are related to motor signs in PD and controls independent of age.

Methods:

Patients were rated with the Unified Parkinson's Disease Rating Scale (subscore A: tremor, rigidity, bradykinesia, and facial expression; subscore B: speech and axial impairment). Steps and time taken to walk 9.144 meters were measured. Total ventricular volume (TVV) and intracranial volume (ICV) were measured on T1-weighted MRI using manual tracing software. WMC were rated on axial T2-weighted, dual-echo or FLAIR MR images using a visual scale.

Results:

TVV (cm3) (PD: 36.48 ± 15.93; controls: 32.16 ± 14.20, p = 0.21) and WMC did not differ between groups (PD: 3.7 ± 4.2; controls: 3.2 ± 3.1, p = 0.55). Age correlated positively with ICV-corrected TVV and WMC in PD (cTVV: r = 0.48, p = 0.003; WMC: r=0.42, p=0.01) and controls (cTVV: r = 0.31, p = 0.04; WMC: r=0.44, p=0.003). Subscore B (r = 0.42, p = 0.01) but not subscore A (r = 0.25, p = 0.14) correlated with cTVV in PD. Steps and walking time correlated with cTVV and WMC in PD; cadence correlated with cTVV and steps with WMC in controls. Age-adjustment eliminated correlations.

Conclusion:

Subscore B, but not subscore A correlated positively with ventricular volume in PD, though this association was accounted for by age. Age-related brain change super-imposed on PD may contribute to axial features.

No global loss of neocortical neurons in parkinson's disease: A quantitative stereological study

The global total number of neocortical neurons was estimated in 10 patients with Parkinson's disease (PD; mean age, 74.8 years; range, 68-83) and compared to 12 comparison subjects (mean age, 75.8 years; range, 70 - 84). The total mean neocortical neuron number in the patients with PD was 18.6 x 10(9) with a coefficient of variation (CV = SD/mean) of 0.18, which was not statistically significantly different from that of the controls (18.8 x 10(9); CV = 0.16; P = 0.90). In contrast to some studies reporting neocortical atrophy this was not confirmed in our study, where the mean volume of neocortex was the same in the two groups (P = 0.59). No difference was found in the volume of white matter, central gray structures, archicortex, or the ventricular system between the two groups. Most patients with PD develop cognitive disturbances with time, and this study cannot exclude that local neuron loss in specific subpopulations of neocortical neurons or cell loss in small but essential neocortical subregions may be part of the structural defects of PD.

Degeneration of substantia nigra in chronic Parkinson's disease visualized by transcranial color-coded real-time sonography

To detect morphologic abnormalities in Parkinson's disease (PD), we examined 30 patients with PD and 30 age- and sex-matched nonparkinsonian controls by transcranial color-coded real-time sonography (TCCS). In 12 severely affected PD patients, the echogenicity of the substantia nigra was distinctly increased. In the remaining 18 PD patients and in all controls, the substantia nigra was poorly visualized or nondetectable by TCCS. The degree of hyperechogenicity of the substantia nigra closely correlated with the severity and duration of PD (p < 0.001). The increased echogenicity of the substantia nigra notably results from nigral gliosis and reflects the stage of degeneration.

Neuropsychological correlates of brain atrophy in Parkinson's disease: a CT-scan study

We examined the presence of cortical or subcortical brain atrophy (as shown by CT scans) in patients with Parkinson's disease (PD) and assessed whether there were significant correlations between CT measurements and the presence of cognitive deficits. There were three main findings. First, patients with bilateral symptoms of PD showed more severe cortical and subcortical atrophy than age-matched normal controls. Second, the presence of unilateral symptoms of PD was significantly associated with contralateral brain atrophy only in patients with right hemi-PD. Third, there was a significant correlation between neuropsychological deficits and atrophy in specific brain areas.

Benign and malignant types of Parkinson's disease: clinical and patho-physiological characterization

Parkinson's disease (P.D.) is characterized by two different types, a benign form found in 85% of patients and a malignant type in 15%. Computer tomography shows malignant patients, in the end stage of the disease process, to exhibit hydrocephalus internus and externus. Such patients exhibit early EEG-deterioration and pharmacotoxic psychosis. The application of neuroleptics to patients with P.D. is associated with an increase in the urinary excretion of acidic metabolites especially of 5-hydroxyindoleacetic acid. It is suggested, that this treatment might also be a useful therapeutic approach to optimizing the residual neuronal function in Parkinson's disease.