Pupillographic Sleepiness Test and Polysomnography in Nondemented Patients with Ischemic White Matter Lesions

Landwehr, Ralf; Liszka, Robert

doi:10.1155/2015/150927

Cited by 2 publications

(3 citation statements)

References 32 publications

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“…The Pupillographic Sleepiness Test (PST) provides quantitative measures of the oscillations that can be used as indices of the degree of sedation (142, 143). Indeed, the two measures of pupil diameter fluctuations generated by the PST (total power, Pupillary Unrest Index), correlate with electroencephalographic and subjective measures of sedation (144, 145).…”

Section: Light-stimulated Sympathetic Pathwaysmentioning

confidence: 99%

Functional Organization of the Sympathetic Pathways Controlling the Pupil: Light-Inhibited and Light-Stimulated Pathways

Szabadi

2018

Front. Neurol.

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Pupil dilation is mediated by a sympathetic output acting in opposition to parasympathetically mediated pupil constriction. While light stimulates the parasympathetic output, giving rise to the light reflex, it can both inhibit and stimulate the sympathetic output. Light-inhibited sympathetic pathways originate in retina-receptive neurones of the pretectum and the suprachiasmatic nucleus (SCN): by attenuating sympathetic activity, they allow unimpeded operation of the light reflex. Light stimulates the noradrenergic and serotonergic pathways. The hub of the noradrenergic pathway is the locus coeruleus (LC) containing both excitatory sympathetic premotor neurones (SympPN) projecting to preganglionic neurones in the spinal cord, and inhibitory parasympathetic premotor neurones (ParaPN) projecting to preganglionic neurones in the Edinger-Westphal nucleus (EWN). SympPN receive inputs from the SCN via the dorsomedial hypothalamus, orexinergic neurones of the latero-posterior hypothalamus, wake- and sleep-promoting neurones of the hypothalamus and brain stem, nociceptive collaterals of the spinothalamic tract, whereas ParaPN receive inputs from the amygdala, sleep/arousal network, nociceptive spinothalamic collaterals. The activity of LC neurones is regulated by inhibitory α2-adrenoceptors. There is a species difference in the function of the preautonomic LC. In diurnal animals, the α2-adrenoceptor agonist clonidine stimulates mainly autoreceptors on SymPN, causing miosis, whereas in nocturnal animals it stimulates postsynaptic α2-arenoceptors in the EWN, causing mydriasis. Noxious stimulation activates SympPN in diurnal animals and ParaPN in nocturnal animals, leading to pupil dilation via sympathoexcitation and parasympathetic inhibition, respectively. These differences may be attributed to increased activity of excitatory LC neurones due to stimulation by light in diurnal animals. This may also underlie the wake-promoting effect of light in diurnal animals, in contrast to its sleep-promoting effect in nocturnal species. The hub of the serotonergic pathway is the dorsal raphe nucleus that is light-sensitive, both directly and indirectly (via an orexinergic input). The light-stimulated pathways mediate a latent mydriatic effect of light on the pupil that can be unmasked by drugs that either inhibit or stimulate SympPN in these pathways. The noradrenergic pathway has widespread connections to neural networks controlling a variety of functions, such as sleep/arousal, pain, and fear/anxiety. Many physiological and psychological variables modulate pupil function via this pathway.

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Section: Light-stimulated Sympathetic Pathwaysmentioning

confidence: 99%

Functional Organization of the Sympathetic Pathways Controlling the Pupil: Light-Inhibited and Light-Stimulated Pathways

Szabadi

2018

Front. Neurol.

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“…• the virtual independence of variations of the vigilance of the subject, • interpretability without the need of further theoretical assumptions. 12 The independence of PTI of the level of vigilance is an important feature especially when examining elderly patients, 23 who tend to get sleepy during an EEG derivation. The parameters we obtained in Ref.…”

Section: Discussionmentioning

confidence: 99%

“…The independence of PTI of the level of vigilance is an important feature especially when examining elderly patients, 23 who tend to get sleepy during an EEG derivation. The parameters we obtained in Ref.…”

Section: Discussionmentioning

confidence: 99%

EEG Synchronization—Parameters in Patients With Subcortical Arteriosclerotic Encephalopathy and Gait Disorder

Yazdani

Yücel

Landwehr

2020

Journal of Clinical Neurophysiology

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Purpose: Subcortical arteriosclerotic encephalopathy (SAE) is characterized by extensive white matter lesions in the MRI. Clinical symptoms are cognitive impairment, ranging from mild deficits to vascular dementia, impaired executive functioning, and gait disorders. In the EEG of SAE patients with vascular dementia, the lower frequencies are increased. However, it is unclear whether EEG changes also exist in SAE patients with gait disorders but without vascular dementia. Methods: The authors analyzed the EEGs of 50 nondemented patients with SAE and gait disorders and 50 healthy controls applying pointwise transinformation as a measure of synchronization. Results: Hundred seconds of waking EEG that appeared unaltered in visual analysis were sufficient to prove changes in synchronization. The authors found a decrease in the mean level of synchronization, combined with an elongation of synchronization time in all examined brain areas. These effects correlated slightly with the extent of subcortical lesions. Conclusions: Changes in EEG synchronization in patients with SAE and gait disorders seem to occur independently of cognitive function. The causal relationship of the changes in EEG synchronization and gait disorders remains to be clarified. The results of this study might point to a decrease in coupling efficiency in these patients, with the increase in synchronization duration as a possible compensatory mechanism. Because a time-efficient signal transmission particularly during gait execution is crucial, reduced efficiency might contribute to an impairment of postural stabilization. The study results might indicate a neuronal network for planning and execution of motor activity and particularly gait, extending from the frontal over the central to the parietal cortex.

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Pupillographic Sleepiness Test and Polysomnography in Nondemented Patients with Ischemic White Matter Lesions

Cited by 2 publications

References 32 publications

Functional Organization of the Sympathetic Pathways Controlling the Pupil: Light-Inhibited and Light-Stimulated Pathways

Functional Organization of the Sympathetic Pathways Controlling the Pupil: Light-Inhibited and Light-Stimulated Pathways

EEG Synchronization—Parameters in Patients With Subcortical Arteriosclerotic Encephalopathy and Gait Disorder

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