Time estimation of depressive patients: the influence of interval content

Time dilation and acceleration in depression

BACKGROUND

A recent meta-analysis left open a significant question regarding altered time perception in depression: Why do depressed people overproduce short durations and under-produce longer durations if their present experience is that time flows slowly? Experience and judgement of time do not seem to accord with one another.

ANALYSIS

By excluding two of the six studies on methodological grounds from a previous meta-analysis of medium-length interval productions, and re-analysing the remaining four studies, the present paper finds that subjective time accelerates from initial dilation within present experience (approximately 1 s duration) to subsequent acceleration within working memory (approximately 30 s duration) when depressed.

PROPOSALS

It is proposed that depressive time dilation and acceleration refer to the default mode and central executive networks, respectively. The acceleration effect is suggested to occur due to mood congruency between long intervals, boredom, and depression. This mood congruency leads to the automatic recall of intrusive, negative, and non-specific autobiographical long-term memories used to judge intervals from previous experience. Acceleration in working memory then occurs according to the contextual change model of duration estimation.

LIMITATIONS

The meta-analysis is limited to four studies only, but provides a potential link between time experience and judgement within the same explanatory model.

CONCLUSIONS

Similarities between psychological time dilation/acceleration and physical time dilation/acceleration are discussed.

Time perception in anxious and depressed patients: A comparison between time reproduction and time production tasks

Several studies reported temporal dysfunctions in anxious and depressed patients. In particular, compared to controls, anxious patients report that time is passing fast whereas depressed patients report that time passes slowly. However, in some studies, no differences between patients and controls are reported. Direct comparison between studies may be complex because of methodological differences, including the fact of conducting investigations with different temporal ranges. In the present study, we tested a group of anxious patients, a group of depressed patients, and a control group with two temporal tasks (time reproduction and time production) with the same temporal intervals (500, 1000 and 1500ms) to further investigate the presence and cause of patients' temporal dysfunctions. Results showed that, compared to controls, anxious patients under-reproduced temporal intervals and depressed patients over-produced temporal intervals. The results suggest that time dysfunction in anxious patients would be mainly due to an attentional dysfunction whereas temporal dysfunction in depressed patients would be mainly due to variations in the pulses' emission rate of the pacemaker.

Aging and the subjective experience of time

BACKGROUND

The subjective experience of time involves several, not yet identified, mechanisms. Many cognitive and emotional factors, such as attention, memory and subjective mental states can influence time estimation.

AIMS

We aimed to assess the subjective experience of time and its relationships with cognitive and emotional characteristics in the elderly.

METHOD

Forty-nine non-demented patients hospitalized for orthopedic rehabilitation underwent an 'ecological' evaluation tool, the semi-structured QUEstionnaire for the Subjective experience of Time (QUEST) requiring retrospective and prospective judgements on self-relevant time intervals. All patients completed tests to assess general cognitive functioning and two questionnaires to evaluate emotional state.

RESULTS

Results showed that accuracy in time estimation did not differ in young-old vs. old-old individuals: both groups performed better on prospective than on retrospective items and on highly than on poorly self-relevant items. Multiple regression analysis showed that performance on QUEST was significantly related to depression and hospitalization duration, but not to age, education, or neuropsychological scores.

CONCLUSIONS

The influence of the emotional state is consistent with theories postulating that the "sense of time" is emergent from emotional and visceral states.

Time perception in depression: a meta-analysis

BACKGROUND

Depressive patients frequently report to perceive time as going by very slowly. Potential effects of depression on duration judgments have been investigated mostly by means of four different time perception tasks: verbal time estimation, time production, time reproduction, and duration discrimination. Ratings of the subjective flow of time have also been obtained.

METHODS

By means of a classical random-effects meta-regression model and a robust variance estimation model, this meta-analysis aims at evaluating the inconsistent results from 16 previous studies on time perception in depression, representing data of 433 depressive patients and 485 healthy control subjects.

RESULTS

Depressive patients perceive time as going by less quickly relative to control subjects (g=0.66, p=0.033). However, the analyses showed no significant effects of depression in the four time perception tasks. There was a trend towards inferior time discrimination performance in depression (g=0.38, p=0.079). The meta-regression also showed no significant effects of interval duration. Thus, the lack of effects of depression on timing does not depend on interval duration. However, for time production, there was a tendency towards overproduction of short and underproduction of long durations in depressive patients compared to healthy controls.

LIMITATIONS

Several aspects, such as influences of medication and the dopaminergic neurotransmitter system on time perception in depression, have not been investigated in sufficient detail yet and were therefore not addressed by this meta-analysis.

CONCLUSIONS

Depression has medium effects on the subjective flow of time whereas duration judgments basically remain unaffected.

Effects of emotional stimuli on time perception in manic and euthymic patients with bipolar disorder

BACKGROUND

Time perception, which plays a fundamental role in decision-making and the evaluation of the environment, is also influenced by emotions. Patients with bipolar disorder have impairments in emotional processing as well as interval timing. We investigated the effects of emotional stimuli on time estimation and reproduction in manic and euthymic bipolar patients compared with healthy controls.

METHODS

We recruited 22 manic bipolar patients, 24 euthymic bipolar patients and 24 healthy controls. Each subject performed time estimation and reproduction tasks using standardized affective pictures that were classified into 4 stimulus groups according to valence and level of arousal and presented for durations of 2, 4, and 6s. We analyzed temporal performance on these tasks using transformed data expressed as a proportion of the target period.

RESULTS

The interactions between arousal and valence were different in manic patients compared with euthymic patients and healthy controls in both time estimation and reproduction tasks. Manic patients showed no effect of positive valence low arousal stimuli in the time estimation task compared to euthymic patients and healthy controls. In the time reproduction task, the effect of emotional stimuli was reversed in manic patients compared to euthymic patients and healthy controls. Significant correlations between the severity of manic symptoms or illness severity and average temporal performance scores were found in manic patients.

CONCLUSION

Our results suggest that altered emotion-related time judgments may be a state-dependent phenomenon observed in manic patients only. This difference in time perception for emotional stimuli may be related to the underlying neurobiological mechanisms of the manic state.

Depression does not affect time perception and time-to-contact estimation

Depressed patients frequently report a subjective slowing of the passage of time. However, experimental demonstrations of altered time perception in depressed patients are not conclusive. We added a timed action task (time-to-contact estimation, TTC) and compared this indirect time perception task to the more direct classical methods of verbal time estimation, time production, and time reproduction. In the TTC estimation task, the deviations of the estimates from the veridical values (relative errors) revealed no differences between depressed patients (N= 22) and healthy controls (N= 22). Neither did the relative errors of the TTC estimates differ between groups. There was a weak trend toward higher variability of the estimates in depressed patients but only at the shortest TTC and at the fastest velocities. Time experience (subjective flow of time) as well as time perception in terms of interval timing (verbal estimation, time production, time reproduction) performed on the same subjects likewise failed to produce effects of depression. We conclude that the notion that depression has a sizeable effect on time perception cannot be maintained.

Time perception at different EEG-vigilance levels

BACKGROUND

Human time perception is influenced by various factors such as attention and drowsiness. Nevertheless, the impact of cerebral vigilance fluctuations on temporal perception has not been sufficiently explored. We assumed that the state of vigilance ascertained by electroencephalography (EEG) during the perception of a given auditory rhythm would influence its reproduction. Thus, we hypothesised that the re-tapping interval length and the accuracy of reproduction performance would vary depending on the state of vigilance determined by EEG.

METHODS

12 female and 9 male subjects ranging from 21 to 38 years (M = 25.52, SD = 3.75) participated in a test paradigm comprising a) a resting EEG for the determination of vigilance while an auditory rhythm was presented, b) a short activity of the proband to be sure of sufficient alertness, and c) a tapping task to reproduce the presented rhythm. Vigilance states of three consecutive 1-sec-EEG-segments of the resting EEG before the reproduction phase were classified using the Vigilance Algorithm Leipzig (VIGALL).

RESULTS AND DISCUSSION

Reproduction accuracy was more precise after high EEG-vigilance stages. Thus, the subjects' mean deviation from the given rhythm was lower (t(17) = -2.733, p < 0.05) after high vigilance stage A (MW = 0.046, SD = 0.049) than after low vigilance stage B (MW = 0.065, SD = 0.067). The re-tapping-length was significantly shorter (t(17) = -2.190, p < 0.05) for reproduction phases following high EEG-vigilance stage A compared to the lower EEG-vigilance stage B.

CONCLUSION

These findings support the hypothesis of a varying time perception and of speed alterations of the internal clock after different states of EEG-vigilance, which were automatically classified by VIGALL. Thus, alterations of cognitive processing may be assessable by specific EEG-patterns.

The effect of mild depression on time discrimination

Depressed mood states affect subjective perceptions of time but it is not clear whether this is due to changes in the underlying timing mechanisms, such as the speed of the internal clock. In order to study depression effects on time perception, two experiments using time discrimination methods with short (<300 ms) and long (>1,000 ms) durations were conducted. Student participants who were categorized as mildly depressed by their scores on the Beck Depression Inventory were less able than controls to discriminate between two longer durations but were equally able to discriminate shorter intervals. The results suggest that mildly depressed or dysphoric moods do not affect pacemaker speed. It is more likely that depression affects the ability to maintain attention to elapsing duration.

How cognitive load affects duration judgments: A meta-analytic review

A meta-analysis of 117 experiments evaluated the effects of cognitive load on duration judgments. Cognitive load refers to information-processing (attentional or working-memory) demands. Six types of cognitive load were analyzed to resolve ongoing controversies and to test current duration judgment theories. Duration judgments depend on whether or not participants are informed in advance that they are needed: prospective paradigm (informed) versus retrospective paradigm (not informed). With higher cognitive load, the prospective duration judgment ratio (subjective duration to objective duration) decreases but the retrospective ratio increases. Thus, the duration judgment ratio differs depending on the paradigm and the specific type of cognitive load. As assessed by the coefficient of variation, relative variability of prospective, but not retrospective, judgments increases with cognitive load. The prospective findings support models emphasizing attentional resources, especially executive control. The retrospective findings support models emphasizing memory changes. Alternative theories do not fit with the meta-analytic findings and are rejected.

Neuropsychology of timing and time perception

Interval timing in the range of milliseconds to minutes is affected in a variety of neurological and psychiatric populations involving disruption of the frontal cortex, hippocampus, basal ganglia, and cerebellum. Our understanding of these distortions in timing and time perception are aided by the analysis of the sources of variance attributable to clock, memory, decision, and motor-control processes. The conclusion is that the representation of time depends on the integration of multiple neural systems that can be fruitfully studied in selected patient populations.

Time experience and time judgment in major depression, mania and healthy subjects. A controlled study of 93 subjects

OBJECTIVE

Studies on the time sense of depressed patients have revealed inconsistent results. Manic patients have been almost neglected.

METHOD

Patients with a major depressive episode (n = 32), or a manic episode (n = 30) (both Diagnostic and Statistical Manual of Mental Disorders-IV, Mini-International Neuropsychiatric Interview-confirmed), and 31 healthy controls were included. The subjective time experience was assessed by a visual analog scale (VAS), the objectively measurable time judgment abilities by the Chronotest, a computer program developed for this study, consisting of time estimation and time production tasks.

RESULTS

Controls reported a balanced, manic patients an enhanced, and depressive patients a slowed experience of time flow in the VAS (P < 0.001). In the time judgment tasks, however, both depressed and manic patients showed time overestimation for the longer time spans (P < 0.008).

CONCLUSION

This largest study on time sense in manic patients confirmed results of a divergent alteration of time experience in depressive and in manic patients but revealed an uniform time overestimation by both patient groups in time judgment tasks.