Eye Movement Latency Research Articles

Regional cerebral blood flow in affective disorder.

The results of two-dimensional cerebral blood flow (CBF) studies in depression and the results of measurements of regional CBF (rCBF) using single photon emission computerized tomography (SPECT) are briefly reviewed. A technical outline of both types of method is described. The majority of SPECT studies point to a decreased CBF in untreated patients with a tendency towards normalization, but other studies suggest that, following treatment, there is an increase above normal either from a decreased or an abnormally high initial level. One study has pointed to unipolar patients having lower flow in the right temporal and parietal lobes relative to normals, whereas non-endogenous patients did not differ significantly from normal controls. Bipolar depressives have been found to have higher flow values than normals in the parietal and temporal lobes in the left hemispheres. This relevant aspect or a possible relationship between type of depression and hemispheric asymmetry needs further study for full classification. Thus, most investigations designed to determine which brain structures might be involved in regulating affect have not been very successful, which may be a consequence of the biological heterogeneity of these disorders or of the limited spatial resolution of the techniques used for investigation. Even if some of these technical difficulties can be overcome with measurements of receptor kinetics supplemented, other biological variables that have proved valuable in psychiatry (such as rapid eye movement latency and biogenic amines) should be studied to find more precise biological markers for depressive illness.

Ambulatory polysomnography of never-depressed borderline subjects: A high-risk approach to rapid eye movement latency

The sleep parameters of never-depressed borderline subjects and age- and sex-matched normal controls were compared by continuous 48-hr ambulatory electroencephalographic (EEG) monitoring. Borderline subjects had a significantly shorter rapid eye movement latency, normal architecture of rapid eye movements sleep, and had familial risks for mood disorders four times greater than in the families of controls. Reduced latency of rapid eye movement can be a trait indicator of liability to depression, present before the clinical appearance of the disorder, and demonstrable in a putative high-risk population.

奥行き方向の視線移動の年齢変化に関する検討

Changes in binocular eye movement occur when a subject changes his/her gaze point from a far/near to a near/far target, requiring both symmetric and asymmetric vergence. We measured these changes to investigate the effects of aging on vergence eye movement. Results indicated increases in the latency and time constants of vergence eye movement, decreases in convergence angle changes, and increases in the number of corrective saccades in subjects over 50 years, and increases in time constants in subjects below 10 years, compared with data for subjects between 10 and 50 years. This suggests that young and older subjects do not have the same vergence eye movement characteristics as those between 10 and 50 years. These differences should be considered in research about a subject's depth perception of stereoscopic images.

Good sleep, bad sleep: A meta-analysis of polysomnographic measures in insomnia, depression, and narcolepsy

Primary insomnia, major depression, and narcolepsy are usually considered to be separate disorders, distinguished by different polysomnographic profiles. But do polysomnographic data provide adequate evidence to segregate the three disorders, or might they display fundamentally the same sleep disturbance, differing only in degree? To test the viability of these two alternate hypotheses, the authors performed a meta-analysis of controlled polysomnographic studies of these disorders. A summary measure of degree of sleep disturbance was constructed from five variables: wakefulness after sleep onset, percentage of stage 1 sleep, percentage of stage 3 + 4 sleep, rapid eye movement (REM) latency, and REM density. The results of available studies for each variable were combined using a weighted average of effect sizes. An overall “sleep disturbance index” was then calculated by combining the estimates for the five above listed variables. On both the individual measures and especially on the summary index, insomnia, depression, and narcolepsy were arrayed on a simple continuum of progressively more severe sleep disturbance-congruent with the clinical observation that these disorders display progressively more disturbed sleep. These findings suggest that sleep can be disturbed in only a limited number of ways: in evaluating sleep architecture, it may not be possible to elaborate much beyond a single axis of good-to-bad sleep. Thus, polysomnographic measures may not provide adequate evidence to classify insomnia, depression, and narcolepsy as separate entities.

Panic disorder and major depression: A comparative electroencephalographic sleep study

Family studies suggest some common etiological factors in panic disorder and depression. The observation of characteristic depression-like polysomnographic alterations in panic disorder patients would further underline the assumed biological interface between the two psychiatric disorders. In a polysomnographic study of 22 inpatients with panic disorder, 12 inpatients with major depression, and 12 control subjects, we found that both groups of patients had one major feature of depression-like sleep: a shortened rapid eye movement (REM) latency. However, the patterns of the first hours of polysomnography showed more differences than similarities between these psychiatric disorders, indicating that the shortened REM latency apparently is merely a common final pathway of different alterations in sleep regulation. Our findings, therefore, provide more evidence against than for a significant biological interface between panic disorder and depression.

Sleep in schizophrenic patients on and off haloperidol therapy. Clinically stable vs relapsed patients.

We examined the state-dependent contribution of neuroleptic withdrawal and psychotic relapse in influencing sleep measures. Eighteen clinically stable male schizophrenic patients taking haloperidol were studied with 3 nights of polysomnography for baseline measures and again after neuroleptic withdrawal. Sleep measures were also obtained at the point of relapse (n = 9) or after a 6-week drug-free period if the patient remained clinically stable (n = 9). Neuroleptic withdrawal led to a global deterioration of rapid eye movement and non-rapid eye movement sleep and a reduction of rapid eye movement latency in both groups. Relapsers differed from nonrelapsers in that they had a larger decrease in total sleep time, sleep efficiency, total non-rapid eye movement sleep, and stage 2 sleep. The level of psychosis was inversely correlated with sleep efficiency, total sleep time, and stage 4 sleep in the drug-free patients. Our data suggest that clinical state needs to be identified in sleep studies of drug-free patients.

Abnormal REM sleep in the irritable bowel syndrome

Motor abnormalities of the small bowel that occur only during the waking state have been reported in the irritable bowel syndrome (IBS), suggesting that central nervous system arousal is a necessary condition for expression of the disorder and that it may reflect inappropriate brain-gut interaction. This possible relationship was explored further by synchronous polysomnography and recording of upper small bowel motility in six healthy subjects and six patients with IBS. During sleep, there was no difference in the patterns of intestinal motility between the two groups. There was no difference between the rapid eye movement (REM) latency or number of REM episodes, but the proportion of REM sleep was markedly increased (36.5% ± 5.7% vs. 18.2% ± 5.7%; P < 0.01) in the IBS group, although the duration of sleep was similar (468 ± 13 minutes in IBS vs. 444 ± 10 minutes in controls; P > 0.1). Sleep apnea was detected in three of six patients with IBS but was not seen in controls. The data are consistent with the model of IBS as a disorder of brain-gut interaction.

Plasma cholinesterase isozymes and REM latency in schizophrenia

The relation between electroencephalographic sleep parameters and plasma cholinesterase isozymes was examined in a group of 19 unmedicated schizophrenic patients. Rapid eye movement (REM) latency was found to be significantly inversely correlated with isozyme 3 (mainly acetylcholinesterase). The results are discussed in relation to cholinergic involvement in the regulation of REM sleep and in the pathophysiology of schizophrenia.

EEG sleep in cushing's disease and cushing's syndrome: comparison with patients with major depressive disorder

Because patients with Cushing' syndrome (CS) and Major depressive disorder (MDD) share features of hypercortisolism and the depressive syndrome, we compared electroencephalographic (EEG) sleep in patients with pituitary-ACTH-dependent Cushing's syndrome (Cushing's disease, CD), patients with ACTH-independent Cushing's syndrome (AICS), patients with major depressive disorder (MDD), and normal subjects. There were substantial similarities in the abnormal polysomnography profiles of patients with CD, AICS, and MDD. All three patient groups demonstrated poorer sleep continuity, shortened rapid eye movement (REM) latency, and increased first REM period density compared with normal subjects. In addition, AICS patients and MDD patients had elevated REM activity and density. These findings are discussed in terms of models of pathophysiology that relate abnormalities in sleep, mood, and hypothalamic-pituitary-adrenal function.

Cholinergic REM sleep induction test in subjects at high risk for psychiatric disorders

The influence of the cholinergic agonist RS 86 on electroencephalographic (EEG) sleep was investigated in 21 healthy members of families identified as being at high risk for psychiatric disorders and in 17 healthy control subjects without any personal or family history of a psychiatric illness. In comparison to the placebo night, the administration of RS 86 led to a shortening of rapid eye movement (REM) latency in both groups. This effect, however, was much more pronounced in the high-risk group, whereas in the control subjects the arousal system and the slow-wave sleep during the first nonREM period were more affected. These observations suggest that the cholinergic action on sleep regulating mechanisms has differing preferential targets in high-risk probands and in control subjects.

Biological correlates of the Newcastle Scale in depressive illness: a multivariate approach.

Rapid eye movement latency (RL), delta max thyroid-stimulating hormone (dmTSH) and 1600 (DST16) and 2300 (DST23) post-dexamethasone cortisol values were determined in a group of 93 depressed patients who were assessed with the Newcastle Endogenous Depression Diagnostic Index (NEDDI). After the effects of age, gender and severity of illness were controlled for, stepwise multiple regression showed that depressive psychomotor activity and weight loss were the 2 NEDDI items most contributing to explain DST23 variance, as was depressive psychomotor activity for dmTSH variance. When the depressive sample was dichotomized according to the presence of these 2 items, the 2 groups had significantly different DST16, DST23, dmTSH and RL values. This suggests that weight loss, agitation and retardation could represent a core feature of a biologically mediated depressive subtype.

CSF chromogranin A-like immunoreactivity in schizophrenia: Relationships with REM latency and slow wave sleep

Chromogranin A (CgA) is a calcium binding protein and a precursor of modulatory peptides in the brain. We measured CgA-like immunoreactivity (CgA-LI) in cerebrospinal fluid (CSF) in 15 male schizophrenic patients (diagnosed by DSM-III-R criteria) after 3 nights of polysomnography. Patients had been drug free for at least 33 days. Our earlier report that CSF CgA-LI in schizophrenic patients correlated significantly with negative symptoms and ventricle-brain ratios, which have been related to slow wave sleep, raised the possibility that CgA-LI might relate to slow wave sleep. CSF CgA-LI was significantly correlated with stage 4 sleep and rapid eye movement latency. Whether these positive relationships between CSF CgA-LI and electroencephalographic sleep measures are specific for schizophrenia awaits further study.

Neural activity in dorsolateral pontine nucleus of alert monkey during ocular following responses.

1. Movements of the visual scene evoke short-latency ocular following responses. To study the neural mediation of the ocular following responses, we investigated neurons in the dorsolateral pontine nucleus (DLPN) of behaving monkeys. The neurons discharged during brief, sudden movements of a large-field visual stimulus, eliciting ocular following. Most of them (100/112) responded to movements of a large-field visual stimulus with directional selectivity. 2. Response amplitude was measured in two components of the neural response: an initial transient component and a late sustained component. Most direction-selective DLPN neurons showed their strongest responses at high stimulus speeds (80-160 degrees/s), whether their response components were initial (63/87, 72%) or sustained (63/87, 72%). The average firing rates of 87 DLPN neurons increased as a linear function of the logarithm of stimulus speed up to 40 degrees/s for both initial and sustained responses. 3. Not only the magnitude but also the latency of the neural and ocular responses were dependent on stimulus speed. The latencies of both neural and ocular responses were inversely related to the stimulus speed. As a result, the time difference between the response latencies for neural and ocular responses did not vary much with changes of stimulus speed. 4. Response latency was measured when a large-field random dot pattern was moved in the preferred direction and at the preferred speed of each neuron. Seventy-three percent (56/77) of the neurons were activated less than 50 ms after the onset of the stimulus motion. In most cases (67/77, 87%), their increase of firing rate started before the eye movements, and 34% of them (26/77) started greater than 10 ms before the eye movements. 5. Blurring of the random dot pattern by interposing a sheet of ground glass increased the latency of both neural responses and eye movements. On the other hand, the blurred images did not change the timing of the effect of blanking the visual scene on the responses of the neurons or eye movements. 6. When a check pattern was used instead of random dots, both neural and ocular responses began to decrease rapidly when the temporal frequency of the visual stimulus exceeded 20 Hz. When the temporal frequency of the visual stimulus approached 40 Hz, the neurons showed a distinctive burst-and-pause firing pattern. The eye movements recorded at the same time showed signs of oscillation, and their temporal patterns were closely correlated to those of the firing rate.(ABSTRACT TRUNCATED AT 400 WORDS)

Relationship between REM sleep latency and nocturnal cortisol concentrations in depressed patients.

Due to conflicting reports on the possible association between shortening of rapid eye movement (REM) latency and increased cortisol secretion in patients with severe depression, this study examined the relationship between REM sleep latency and nocturnal cortisol concentration in 12 outpatients with major depression. The results showed a significant inverse correlation (r = -0.71, P < 0.01) between REM sleep latency and mean (23.00 hours-03.00 hours) plasma cortisol concentration. Age and severity of depression did not contribute to the inverse relationship. REM activity and density during the first REM period showed no significant correlations with the cortisol measures. A review of the literature suggests that this relationship might be unique to subjects with major depression, and again raises the possibility that these biological disruptions may have a common neurochemical basis.

Electroencephalographic sleep abnormalities in schizophrenia. Relationship to positive/negative symptoms and prior neuroleptic treatment.

Polysomnographic abnormalities in schizophrenia are not well characterized and their associations with schizophrenic symptomatology have not been adequately assessed. To address these issues, we recorded electroencephalographic sleep in 20 drug-naive schizophrenics, 20 drug-free but previously medicated schizophrenics, and 15 normal controls. Drug-naive and previously medicated patients had significantly greater impairment of sleep continuity and shorter rapid eye movement latency when compared with controls. In the previously medicated group, findings were significantly influenced by duration of drug-free status. Rapid eye movement latency was inversely correlated with the severity of negative symptoms (r = -.52) but was unrelated to depressive symptoms. Slow-wave sleep did not differ between schizophrenic patients and normal controls and was unrelated to any clinical parameter. Mechanisms underlying the observed associations between rapid eye movement sleep abnormalities and negative symptoms in the acute phase of schizophrenic illness need to be explored.

Eye movements in myotonic dystrophy.

Smooth pursuit eye movements were studied with infrared reflection equipment in 10 patients with myotonic dystrophy and in 10 age- and sex-matched controls. Smooth pursuit gain, measured after correction for catch-up saccades, was decreased in the patient group. Normal latencies of saccadic eye movements made a lack of attention an unlikely explanation for this low gain. Likewise, presence of catch-up saccades and normal fixation made it unlikely that extra-ocular myopathy explained the low smooth pursuit gain. We suggest that periventricular white matter abnormalities represent a more likely explanation.

Electroencephalographic sleep in spousal bereavement and bereavement-related depression of late life

Although spousal bereavement in late life is common and frequently leads to major depression, the boundary between bereavement without a depressive syndrome and bereavement-related depression has been insufficiently studied from a physiological perspective. Because other forms of depression are associated with physiological changes, including sleep, we have attempted to clarify the relationship of bereavement and bereavement-related depression by investigating electroencephalographic (EEG) sleep in 31 elderly volunteers with recent spousal bereavement, stratified by the presence ( n = 15) or the absence ( n = 16) of major depression (Research Diagnostic Criteria). Entry into the study was limited to volunteers without a personal history of psychiatric disorder. As hypothesized, bereaved subjects with major depression had significantly lower sleep efficiency, more early morning awakening, shorter rapid eye movement (REM) latency, greater REM sleep percent, and lower rates of delta wave generation in the first nonREM (NREM) period, compared with bereaved subjects without depression. Furthermore, the sleep of bereaved subjects with single-episode major depression resembled that of elderly patients with recurrent unipolar major depression ( n = 15) on measures noted above. Sleep in bereavement without depression was similar to that of 15 healthy control subjects (neither bereaved nor depressed). These findings suggest that the current DSM-III-R concept of uncomplicated bereavement is not confirmed, as the sleep patterns of subjects who develop a depressive syndrome in the context of bereavement, many of whom might be considered to have “uncomplicated bereavement” by DSM-III-R standards, are identical to sleep patterns found in major depressive episodes. To our knowledge, this is the first study of EEG sleep in spousal bereavement with and without major depression.

Oculomotor Control and Cognitive Processes: Normal and Pathological Aspects

Neural networks applied to the oculomotor system (D.A. Robinson). Eye movements in neurological diagnosis: Huntington's disease and congenital nystagmus (D.S. Zee). Neurophysiology of Eye Movements. Localization of targets in humans: the role of ocular muscle proprioception (D. Nommay et al). Effects of severance of the vestibular commissural pathway on the neural integrator of the oculomotor system in cat (E. Godaux, G. Cheron). Representation of three-dimensional eye movements in the cerebellar flocculus of the rabbit (J. van der Steen et al). Effects of floccular injections of noradrenergic agonists and antagonists on adaptive changes in the VOR gain (J. van Neerven et al). The Control of Eye Movements. Human vestibuloocular reflex (VOR) and vestibular velocity storage as influenced by optokinetic stimuli (E. Koenig et al). Vertical gaze stability in cat: otolithic contribution (V.E. Pettorossi et al). Post-rotational nystagmus suppression by the presentation of a single visual target in cat and man (G. Magenes et al). Adaptive mechanisms in the monkey saccadic system (P. Inchingolo et al). Human express saccades: catch trails influence the probability of their occurrence (M. Juttner, W. Wolf). Eye-Head Coordination. Adaptation of eye and head movements to reduced peripheral vision (G.M. Gauthier et al). Coupled and dissociated modes of eye-head coordination in humans to flashed visual target (S. Ron, A. Berthoz). Superior colliculus and feedback control of gaze shift in the head-free cat (D. Pelisson et al). Strategies of eye-head coordination (R. Schmid, D. Zambarbieri). Eye Movements in Pathology. Sensory and motor aspects of congenital nystagmus (R.V. Abadi et al). Head-shaking nystagmus - A clinical tool to detect peripheral and central vestibular asymmetries (M. Fetter et al). Saccadic and smooth pursuit eye movements in olivo-ponto-cerebellar atrophies (M. Spanio et al). Slow eye movement abnormalities in Wallenberg's lateral medullary syndrome (W. Waespe). Eye tracking dysfunctions in schizophrenic patients - Why is there no neuroleptic side-effect? (N. Hock et al). Eye Movements and Cognitive Processes. A mathematical analysis of the convenient viewing position hypothesis and its components (M. Brysbaert, G. d'Ydewalle). Is there an optimal landing position in words during reading of texts? (F. Vitu, J.K. O'Regan). Processing of prepositions as reflected by gaze durations (A. Wilbertz et al). The latency of saccadic eye movements to texture-defined stimuli (H. Deubel, H. Frank). Does thinking aloud influence the structure of cognitive processes? (U. Lass et al). Eye movements in visual search: a test of the limited cognitive effort hypothesis and an analysis of the search operating characteristic (A.M. Jacobs). Applied Research. Colour, effective contrast and search performance (J.L. Barbur et al). Video-oculography - An alternative method for measurement of three-dimensional eye movements (A.H. Clarke et al).

Electroencephalographic sleep and cerebral morphology in functional psychoses: A preliminary study with computed tomography

We investigated the association between cerebral morphology as revealed by computed tomography and sleep polysomnographic findings in patients with functional psychoses. The third ventricle-brain ratios, caudate ratios, and anterior horn ratios were significantly negatively associated with sleep maintenance and were positively correlated with rapid eye movement (REM) latency. When the effects of illness severity were covaried out, the relation between REM latency and anterior horn ratios remained significant. Disturbances in sleep in some patients with schizophrenia and schizoaffective disorders may be related to dysfunction of forebrain structures, and may be similar to those seen in dementia.

Adjustment disorders of sleep: The sleep effects of a major stressful event and its resolution

Seventy volunteers had 3 nights of sleep recording during a period of marital separation, and 61 returned for repeat studies 1 year later. At that time, the divorce was final for 42. Forty of the volunteers were depressed when first screened, and 30 were not. Initially all those undergoing marital separation had less delta sleep than an age-matched married comparison sample. Delta increased at followup for those whose divorce was completed. Rapid eye movement (REM) latency was reduced and REM percent was elevated only in the depressed. Among the not depressed, those whose divorces remained incomplete at the followup had lower delta, higher REM percent, and shorter REM latency than did those whose divorces were finalized. This suggests that prolonged emotional stress may put these subjects at some risk for a mood disorder.