Biomedical subjects

F Hohagen

Publications and source records attributed to F Hohagen.

75 records · Page 5Linked to original sources

PubMedDate not supplied

Cholinergic REM induction test: muscarinic supersensitivity underlies polysomnographic findings in both depression and schizophrenia.

Disinhibition of rapid eye movement (REM) sleep (e.g. shortening of REM latency, heightened REM density) is frequently encountered in patients with a major depressive disorder (MDD). Administration of cholinomimetics prior to or during sleep leads to a more pronounced advance of REM sleep in depressed patients compared to healthy controls and patients with other psychiatric disorders. The present study tested whether the cholinergic REM induction test (CRIT) with 1.5 mg RS 86 (an orally acting muscarinic agonist) differentiates patients with MDD (n = 40) from those with schizophrenia (n = 43) and healthy controls (n = 36). The most pronounced shortening of REM latency after cholinergic stimulation occurred in patients with MDD. However, a significant number of patients with schizophrenia also displayed short REM latencies (REM latency < 25 minutes) under placebo conditions and after cholinergic stimulation. REM density measures more clearly differentiated patients with MDD from those with schizophrenia. It is concluded that a subgroup of patients suffering from schizophrenia displays signs of a muscarinic receptor supersensitivity.

Adolescent↗

PubMedDate not supplied

The value of REM sleep parameters in differentiating Alzheimer's disease from old-age depression and normal aging.

Pseudodementia as a common trait in elderly depressives presents a major problem in gerontopsychiatry, especially for the differential diagnosis between Old-Age Depression (OAD) and Dementia of the Alzheimer Type (DAT). The present polysomnographic study examined parameters of sleep continuity, sleep architecture, and REM sleep to differentiate DAT from OAD. The investigation was based on the theoretical framework of the cholinergic-aminergic imbalance model of depression, the cholinergic deficit hypothesis of Alzheimer's disease and the reciprocal interaction model of Non-REM/REM sleep regulation, according to which REM sleep parameters should have high discriminative value to differentiate OAD and DAT. We investigated 35 DAT patients, 39 OAD patients and 42 healthy controls for two consecutive nights in the sleep laboratory. The DAT patients were in relatively early/mild stages of the disease, the severity of depression in the OAD group was moderate to severe. Depressed patients showed characteristic 'depression-like' EEG sleep alterations, i.e. a lower sleep efficiency, a higher amount of nocturnal awakenings and decreased sleep stage 2. Sleep continuity and architecture in DAT was less disturbed. Nearly all REM sleep measures differentiated significantly between the diagnostic groups. OAD patients showed a shortened REM latency, increased REM density and a high rate of Sleep Onset REM periods (SOREM), whereas in DAT REM density was decreased in comparison to control subjects. REM latency in DAT was not prolonged as expected. To assess the discriminative power of REM sleep variables a series of discriminant analyses were conducted. Overall, 86% of patients were correctly classified, using REM density and REM latency measures. Our findings suggest that REM density as an indicator of phasic activity appears to be more sensitive as a biological marker for the differential diagnosis of OAD and DAT than REM latency. The results support the role of central cholinergic neurotransmission in REM sleep regulation and the pathogenesis of DAT and OAD.

Aged↗

PubMedDate not supplied

Cholinergic and noradrenergic neurotransmission: impact on REM sleep regulation in healthy subjects and depressed patients.

The reciprocal interaction model of NonREM- and REM sleep regulation suggests that the cycling alternating pattern of Non-REM- and REM sleep is under the control of noradrenergic/serotonergic and cholinergic neuronal networks. This model was tested in healthy humans by administration of cholinergic agonists/antagonists and noradrenergic antagonists prior to or during sleep. Cholinomimetics like physostigmine, RS 86 and galanthamine provoked an earlier onset of REM sleep, whereas subchronic treatment with scopolamine, a cholinergic antagonist, only led to a heightening of REM density. Simultaneous administration of noradrenergic antagonists with a cholinergic agonist did not provoke a more pronounced REM sleep advance. Comparative studies with the cholinergic agonist RS 86 in depressed patients, schizophrenic patients and patients with other psychiatric disorders revealed the most pronounced REM sleep response in the depressed group. The REM sleep response to cholinergic stimulation in depression did however not predict the treatment response to a differential-therapeutic strategy.

Adolescent↗