Most cerebral imaging studies of patients with progressive supranuclear palsy (PSP) have noted subtle atrophy, although the full extent of atrophy and any cor relates to clinical features have not been determined. We ...Most cerebral imaging studies of patients with progressive supranuclear palsy (PSP) have noted subtle atrophy, although the full extent of atrophy and any cor relates to clinical features have not been determined. We used voxel-based morp hometry analysis of grey matter, white matter and CSF on MRI brain scans to map the statistical probability of regional tissue atrophy in 21 patients with PSP, 17 patients with Parkinson’s disease and 23 controls. PSP and Parkinson’s dise ase cohorts were selected to approximate the mid-stages of their respective dis ease courses. Where regions of significant tissue atrophy were identified in a d isease group relative to controls, the probability of tissue loss within those r egions was correlated with global indices of motor disability, and behavioural a nd cognitive disturbance for that disease group. Minimal regional atrophy was ob served in Parkinson’s disease. PSP could be distinguished from both controls an d Parkinson’s disease by symmetrical tissue loss in the frontal cortex (maximal in the orbitofrontal and medial frontal cortices), subcortical nuclei (midbrain , caudate and thalamic) as well as periventricular white matter. For PSP, motor deficits correlated with atrophy of the caudate and motor cingulate, while behav ioural changes related to atrophy in the orbitofrontal cortex and midbrain. Thes e data suggest that intrinsic neurodegeneration of specific subcortical nuclei a nd frontal cortical subrogions together contribute to motor and behavioural dist urbances in PSP and differentiate this disorder from Parkinson’s disease within 2-4 years of symptom onset.展开更多
Background: The head-tilt phenomenon (difference between the vertical deviati ons with an ipsilateral and contralateral headtilt by 45 deg. each) occurring in patients with a superior oblique palsy has traditionally b...Background: The head-tilt phenomenon (difference between the vertical deviati ons with an ipsilateral and contralateral headtilt by 45 deg. each) occurring in patients with a superior oblique palsy has traditionally been explained by the lacking contraction of the superior oblique muscle within the synkinetic movemen t of ocular counterrolling. However, using a computer model, Robinson showed that the superior oblique palsy itself causes only a relatively small head-tilt ph enomenon. Adaptive mechanisms amplifying the otolith reflex were suggested to ex plain the increase of the head-tilt phenomenon in the course of time. In order to reduce the abnormal head posture required for binocular vision, the otolith r eflex would be amplified, accepting the greater vertical deviation when the head is tilted to the paretic side [23]. Question: If the head-tilt phenomenon were solely caused by the lacking contraction of the superior oblique muscle, it sho uld be greater in bilateral than in unilateral superior oblique palsies. If an a daptive mechanism were acting to reduce the abnormal head posture, the head-til t phenomenon should not be greater, and could even be smaller in bilateral than in unilateral superior oblique palsy, because in bilateral (symmetric) trochlear nerve palsies the vertical deviation at straight gaze is already small or absen t without adaptation. Patients and Methods: We have carried out a retrospective comparison of 10 patients with bilateral symmetric superior oblique palsies and 10 patients with unilateral superior oblique palsy. In all cases, the palsy was acquired and had been present for at least 1 year. Results: The patients with bi lateral superior oblique palsy had a head-tilt phenomenon ranging from 0 to 7 d egrees (median, 2 deg.). The patients with unilateral superior oblique palsy had a head-tilt phenomenon between 2 and 13 degrees (median, 8 deg.). The differen ce was significant (p=0.0117). Conclusions: The head-tilt phenomenon is smaller in long-standing bilateral symmetric superior oblique palsies than in long-st anding unilateral superior oblique palsy. This finding supports the hypothesis t hat in unilateral superior oblique palsy, an adaptive mechanism augments the hea d-tilt phenomenon by an amplification of the otolith reflex. However, we presum e that the amplification of the otolith reflex is only a side effect of the adap tive change of the vertical fusional vergence tonus and thus the price of the im proved vertical fusion, rather than a compensatory mechanism.展开更多
文摘Most cerebral imaging studies of patients with progressive supranuclear palsy (PSP) have noted subtle atrophy, although the full extent of atrophy and any cor relates to clinical features have not been determined. We used voxel-based morp hometry analysis of grey matter, white matter and CSF on MRI brain scans to map the statistical probability of regional tissue atrophy in 21 patients with PSP, 17 patients with Parkinson’s disease and 23 controls. PSP and Parkinson’s dise ase cohorts were selected to approximate the mid-stages of their respective dis ease courses. Where regions of significant tissue atrophy were identified in a d isease group relative to controls, the probability of tissue loss within those r egions was correlated with global indices of motor disability, and behavioural a nd cognitive disturbance for that disease group. Minimal regional atrophy was ob served in Parkinson’s disease. PSP could be distinguished from both controls an d Parkinson’s disease by symmetrical tissue loss in the frontal cortex (maximal in the orbitofrontal and medial frontal cortices), subcortical nuclei (midbrain , caudate and thalamic) as well as periventricular white matter. For PSP, motor deficits correlated with atrophy of the caudate and motor cingulate, while behav ioural changes related to atrophy in the orbitofrontal cortex and midbrain. Thes e data suggest that intrinsic neurodegeneration of specific subcortical nuclei a nd frontal cortical subrogions together contribute to motor and behavioural dist urbances in PSP and differentiate this disorder from Parkinson’s disease within 2-4 years of symptom onset.
文摘Background: The head-tilt phenomenon (difference between the vertical deviati ons with an ipsilateral and contralateral headtilt by 45 deg. each) occurring in patients with a superior oblique palsy has traditionally been explained by the lacking contraction of the superior oblique muscle within the synkinetic movemen t of ocular counterrolling. However, using a computer model, Robinson showed that the superior oblique palsy itself causes only a relatively small head-tilt ph enomenon. Adaptive mechanisms amplifying the otolith reflex were suggested to ex plain the increase of the head-tilt phenomenon in the course of time. In order to reduce the abnormal head posture required for binocular vision, the otolith r eflex would be amplified, accepting the greater vertical deviation when the head is tilted to the paretic side [23]. Question: If the head-tilt phenomenon were solely caused by the lacking contraction of the superior oblique muscle, it sho uld be greater in bilateral than in unilateral superior oblique palsies. If an a daptive mechanism were acting to reduce the abnormal head posture, the head-til t phenomenon should not be greater, and could even be smaller in bilateral than in unilateral superior oblique palsy, because in bilateral (symmetric) trochlear nerve palsies the vertical deviation at straight gaze is already small or absen t without adaptation. Patients and Methods: We have carried out a retrospective comparison of 10 patients with bilateral symmetric superior oblique palsies and 10 patients with unilateral superior oblique palsy. In all cases, the palsy was acquired and had been present for at least 1 year. Results: The patients with bi lateral superior oblique palsy had a head-tilt phenomenon ranging from 0 to 7 d egrees (median, 2 deg.). The patients with unilateral superior oblique palsy had a head-tilt phenomenon between 2 and 13 degrees (median, 8 deg.). The differen ce was significant (p=0.0117). Conclusions: The head-tilt phenomenon is smaller in long-standing bilateral symmetric superior oblique palsies than in long-st anding unilateral superior oblique palsy. This finding supports the hypothesis t hat in unilateral superior oblique palsy, an adaptive mechanism augments the hea d-tilt phenomenon by an amplification of the otolith reflex. However, we presum e that the amplification of the otolith reflex is only a side effect of the adap tive change of the vertical fusional vergence tonus and thus the price of the im proved vertical fusion, rather than a compensatory mechanism.
