INTRODUCTION

IDENTIFICATION OF TEMPORAL PROCESSING DOMAINS RELEVANT TO ASSESSMENT OF PSYCHOTIC ILLNESS: DEVELOPMENT OF THE INTEGRITY OF TEMPORAL PROCESSING (ITP) BATTERY.

SARAH E. FORSTER, RYAN J. LACKNER, AND WILLIAM P. HETRICK

DEPT. OF PSYCHOLOGICAL & BRAIN SCIENCES, INDIANA UNIVERSITY, BLOOMINGTON, IN

APPROACH & PLANNED ANALYSIS

PARTICIPANTS & PROCEDURES

▪ Efforts to identify a common denominator in the characteristically heterogeneous clinical presentation of schizophrenia

have prompted the suggestion that a disturbance of temporal processing may underlie positive, negative, and disorganized

dimensions of schizopathology (Fuchs, 2007; Andreasen, 1999).

▪ According to this perspective, the abnormal perceptual experiences, disorganized thought, and disordered behavior that

typify schizophrenia can be attributed to a fundamental failure in the temporal coordination of sensory, cognitive, and

motor processes. Similarly, a central disturbance of temporal processing integrity may also provide a common

provenance for the diversity of cognitive deficits observed in conjunction with the disorder and thought to be integral to

long term functional impairment.

▪ While a recent impetus to discern mechanisms of cognitive dysfunction in schizophrenia has spurred a movement to

efficiently and consistently characterize specific domains of impairment (Green, et al., 2004; Carter, et al., 2008),

resulting assessment tools have heretofore omitted assessment of temporal processing ability.

▪ The current study aims to address this gap in measurement by developing a standardized battery for the assessment of

temporal processing dysfunction in schizophrenia-spectrum psychopathology. In order to achieve a comprehensive

assessment tool, task selection was informed by an extant dimensional analysis of timing ability (Rammsayer & Brandler,

2004) and review of relevant neuroimaging findings (Lewis & Miall, 2003; Penney & Vaitilingam, 2008; Wiener,

Turkeltaub, & Coslett, 2010; Coull & Nobre, 2008). Specifically, tasks probing timing ability across sub- and supra-

second, motor and non-motor, and implicit/predictive vs. explicit/reflective domains were selected for inclusion.

Participants:

▪Target Enrollment: 60 healthy individuals and 40 individuals with schizotypal personality traits will be enrolled in

the current study protocol. Individuals in the schizotypal trait group will exhibit subclinical expressions of

schizophrenic psychopathology such as ideas of reference, odd beliefs or magical thinking, odd thought process or

speech, suspiciousness or paranoia, abnormal affective expression, and social isolation.

▪Recruitment: Participants will be recruited through advertisements posted in the community and online.

Advertisements targeting individuals with schizotypal traits will specify features of schizotypy amongst study

eligibility requirements (e.g. a belief in telepathy or spirits).

▪Pilot Sample: The current sample includes 20 healthy individuals (8 males, Mean Age = 23 (SD = 5).

Procedures:

▪Session Structure: All temporal processing paradigms and self-report assessments are administered on the same

day. Additional cognitive testing and collection of cerebellar-dependent measures is conducted during a separate

visit. All tasks are administered in a fixed order. Each session is 1.5-2 hours in duration.

▪Stimulus Presentation: E-Prime software (Psychology Software Tools) was utilized for paradigm design and

presentation.

PRELIMINARY FINDINGS & CONCLUSIONS

Temporal Bisection

Velocity Judgment

Method of Dynamic

Stimuli

Causality Judgment

Finger Tapping

Temporal

Reproduction

Magnitude

Estimation

Auditory Flutter

Fusion

Temporal Order

Judgment

Auditory stimuli are comprised of 12 tempos, ranging from 1.45 to 2 Hz. Gradual

acceleration/deceleration of the tempo occurs on 75% of trials. Participants respond upon detection

of tempo change and classify as acceleration vs. deceleration (see Roy, et al., 2012).

Participants observe a point moving at a constant velocity before passing behind an occluder.

During occlusion, the point is perturbed on 80% of trials to appear earlier or later than expected.

Participants must detect and report changes in velocity during occlusion.

Participants classify auditory stimuli with reference to ‘short’ (300 ms) and ‘long’ (600 ms)

standard durations. Test stimuli are 880 Hz tones, ranging from 300-600 ms. Participants

complete 3 blocks of 35 trials, each preceded by review of standard durations.

Participants learn a fixed temporal contingency (250, 500, or 1,000 ms) between actions

(button press) and outcomes (target hit) before each block. Participants are asked to attribute

unexpected temporal contingencies (early or late) to the actions of another player.

Participants complete 6 blocks of tone- and self-paced finger tapping. Blocks begin with a

sequence of twelve 50 ms tones at 500 ms intervals. Participants tap in time to tones and then

continue with self-paced tapping for 30 counts after tones have been discontinued.

Participants reproduce 140 intervals ranging in duration from 500 ms to 3 s. Intervals are

presented using either auditory (tone) or visual (shape) cues and are either filled (stimulus on

during interval) or unfilled (stimuli demarcate an empty interval).

Participants estimated the duration (in ms) of 56 intervals, ranging in duration from 500 ms to 3 s.

Intervals are presented using either auditory (tone) or visual (shape) cues and are either filled (stimulus

on during interval) or unfilled (stimuli demarcate an empty interval).

Participants listen to bursts of white noise, separated in time by 1 to 60 ms. On each trial,

participants indicate whether 1 or 2 bursts have been detected. A self-adjusting staircase procedure

is used to estimate the 75% detection threshold (see Hairston, et al., 2008 for details).

Participants listen to high-low and low-high tone sequences, separated in time by 1 to 150 ms.

On each trial, participants indicate whether the high tone preceded the low tone or vice versa. A

self-adjusting staircase procedure is used to estimate the 75% detection threshold (see Hairston,

et al., 2008 for details).

▪ A dimensional analysis of temporal processing ability by Rammsayer & Brandler (2004) has

established important support for a common timing mechanism across duration discrimination,

temporal generalization, and temporal order judgment tasks in healthy individuals.

▪ The current study will employ a similar approach to discern domains of temporal processing

function within a sample in which substantive inter-individual variability is expected to coincide

with schizophrenia-spectrum psychopathology.

▪ Dependent measures from 9 timing tasks will be entered into an exploratory factor analysis

(EFA). Factor solutions and factor loadings will inform 1.) development of composite scores to

quantify individual performance within and across domains and 2.) elimination of redundant tasks

from the ITP Battery.

Temporal Processing Ability vs. Cognitive Control (n=16) Temporal Processing Ability vs.

Perceptual Anomalies (n=19)

Preliminary Findings:

▪ Correlations between temporal processing indices and cognitive control measures were explored within a pilot sample of

16 individuals. Trend-level correlations revealed negative associations between the magnitude of post-error slowing and

performance measures derived from temporal reproduction (response error), temporal bisection (bisection point), and

causality judgment (error rate) tasks. Bonferroni correction for multiple comparisons was not applied.

▪ Correlations between temporal processing indices and self report clinical indicators were also explored (n = 19). A

significant negative correlation was noted between performance on the temporal bisection task (bisection point) and

Sensory Gating Inventory score. Bonferroni correction for multiple comparisons was not applied.

Task Dependent Variable –

Primary [Secondary]

MDS Fn [Error Rate]

Velocity Error Rate

Bisection DL [BP, WF]

Causality Error Rate

Tapping Mean ITI [SD ITI]

Reproduction Response Error [Relative Error]

Estimation Response Error [Relative Error]

AFF 75% Threshold

TOJ 75% Threshold

Hypothetical Distribution of

3 Variables by Group

EFA

▪ Individual composite scores will be computed for each factor identified in the EFA analysis.

Composite scores will reflect factor loadings assigned to each dependent variable in the factor

solution.

▪ Composite scores will be entered into a post hoc correlational analysis to explore relationships

between identified temporal processing domains, cognitive variables (e.g. executive working

memory, IQ, post-error slowing), cerebellar-dependent measures (e.g. postural stability, eye blink

conditioning), and clinical indices (e.g. schizotypal traits, sensory gating deficits).

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development in schizophrenia: an overview of the first meeting of the Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia Initiative. Biol Psychiatry, 64(1), 4-10.; Coull, & Nobre, (2008). Dissociating explicit timing from

temporal expectation with fMRI. Curr Opin Neurobiol, 18(2), 137-144.; Fuchs, (2007). The temporal structure of intentionality and its disturbance in schizophrenia. Psychopathology, 40(4), 229-235.; Green, et al. (2004). Approaching a consensus cognitive

battery for clinical trials in schizophrenia: the NIMH-MATRICS conference to select cognitive domains and test criteria. Biol Psychiatry, 56(5), 301-307.; Hairston & Maldjian, (2008) An adaptive staircase procedure for the E-Prime programming

environment. Comput Methods Programs Biomed, doi:10.1016/j.cmpb.2008.08.003; Lewis & Miall, (2003b). Distinct systems for automatic and cognitively controlled time measurement: evidence from neuroimaging. Curr Opin Neurobiol, 13(2), 250-255.;

Penney & Vaitilingam, (2008). Imaging Time. In S. Grondin (Ed.), Psychology of Time (pp. 261-294). Bingley, UK: Emerald Group Publishing.; Rammsayer & Brandler, (2004). Aspects of temporal information processing: a dimensional analysis.

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Neuroimage, 49(2), 1728-1740.

Conclusions: Preliminary findings suggest that individuals with enhanced post-error slowing may tend to under-produce temporal

intervals, exhibit a ‘short’ classification bias during temporal bisection, and achieve superior accuracy in causality judgments. In addition, a

lower bisection point was also predictive of increased incidence of perceptual and attentional anomalies, associated with impaired sensory

gating. Importantly, preliminary results demonstrate ‘proof of concept’ and support the inclusion of selected cognitive and clinical measures

in the planned analysis.