The "Rod and Fran Test": relationship priming influences cognitive-perceptual performance.

We theorized that interpersonal relationships can provide structures for experience. In particular, we tested whether primes of same-sex versus mixed-sex relationships could foster cognitive-perceptual processing styles known to be associated with independence versus interdependence respectively. Seventy-two participants visualized either a same-sex or other-sex relationship partner and then performed two measures of cognitive-perceptual style. On a computerized Rod and Frame Test, individuals were more field-dependent after visualizing a mixed-sex versus same-sex relationship partner. On a measure involving perceptions of group behavior, participants demonstrated more holistic/contextually based perception after being primed with a female versus male relationship partner. These findings support the hypothesis that activated cognitive structures representing interpersonal relationships can shape individuals' cognitive-perceptual performance.

Perceptual lateralization on the Rod-and-Frame Test in young and older adults.

INTRODUCTION: There is an overall left visual field/right hemisphere advantage in young adults for masked, tachistoscopically presented images on the Rod-and-Frame Test (RFT). This study explored potential age-related lateralization differences in processing of visual context on the RFT. METHODS: The 35 young and 33 older adults aligned a rod surrounded either by no frame, a vertical, or leftward/rightward tilted frame to their perceived vertical. Algebraic errors of rod alignment were used to derive the rod-and-frame effect (RFE) and asymmetry index. RESULTS: Young adults had frequent indirect effects, mostly to the right-tilted frame, while older adults hardly produced any. Compared with nontilted frames, young adults displayed larger alignment errors with left-tilted frames; however, older adults exhibited this same effect for both frame tilt conditions. Young adults had smaller RFE values than older adults for the right-tilted frame, with no age-related difference in RFE for the left-tilted frame or asymmetry index. The negative asymmetry index was statistically different from the true vertical only in young adults. CONCLUSION: There is an age-related reduction in the right hemisphere processing of left-sided visual contexts on the RFT. Such findings can assist clinicians to improve interpretation of RFT findings in clinical patients.

Symptom severity is associated with leftward lateralization upon contextual modulation of visual vertical in patients with schizophrenia.

Background: Contextual processing dysfunction in patients with schizophrenia (SCZ) is not uniform and task-dependent. In SCZ, studies on the rod and frame test (RFT), which evaluates contextual modulation of verticality perception, are sparse. A main study that utilized a two-alternative forced choice design for judging rod verticality reported equivalent strength of RFT contextual modulation in healthy controls and SCZ. The current study aims to uncover any potential differences in contextual modulation between controls and SCZ with an adjustment method on a computerized RFT. Materials and methods: A total of 17 healthy controls and 15 SCZ aligned an oriented rod to their perceived vertical with a computer mouse under four randomized frame presentations: absent frame, non-tilted (Frame0°), or tilted by 18 degrees leftward (Frame-18°) or rightward (Frame+18°). Rod deviation error was assigned a negative or positive value when aligned leftward or rightward, respectively, of 0°. Signed and absolute errors, the rod and frame effect (RFE), and intra-individual variability (inconsistency) were used for analysis. Results: There was no group difference in rod alignment errors or derived measures, except that SCZ displayed greater inconsistency in rod alignment, compared to controls. The negative symptom scale (PANSS-N) scores correlated positively with the variability measure and with unsigned Frame-18° error. Conclusions: Only the variability measure was sensitive enough to distinguish between controls and SCZ. SCZ with more severe negative symptoms had larger variability in rod alignment, probably reflecting a state of indifference. The larger deviation errors only with a leftward tilted frame, as PANSS-N scores increased, may indicate a lateralized attentional abnormality that is correlated with severity of symptoms in SCZ.

Perceptual visual dependence for spatial orientation in patients with schizophrenia.

BACKGROUND: Patients with schizophrenia are reported to have vestibular dysfunction and to weigh vestibular input to a lesser extent compared to healthy controls. Such deficits may increase visual dependence (VD) for spatial orientation at a perceptual level in these patients. The aim of this study is to compare VD levels between healthy control and patients with schizophrenia and to explore associations between VD and clinical measures in these patients. Relation of VD to antipsychotic drug treatment is also discussed. METHOD: 18 patients with schizophrenia and 19 healthy controls participated in this study. The Rod and Disc Test (RDT) was used to create an optokinetic surround around a centrally located rod. Participants aligned the rod to their subjective visual vertical (SVV) in both static and dynamic disc conditions. VD was calculated as the difference in SVV between these two conditions. RESULTS: There was no group difference or gender difference in static or dynamic SVV as well as VD. There was no correlation between VD and any of the Positive and Negative Syndrome Scale (PANSS) scores, however VD was significantly correlated to illness duration in the patient group. CONCLUSIONS: Schizophrenia is not associated with greater VD levels at a perceptual level, compared to controls, indicating adequate visuo-vestibular integration for judging line verticality in these patients. Patients with greater chronicity of the disease are more visually dependent than those less chronically ill, consistent with previous reports of possible vestibular dysfunction in patients with schizophrenia. This may affect their daily functioning in dynamic visual environments.

Young and Older Adults Differ in Integration of Sensory Cues for Vertical Perception.

INTRODUCTION: The subjective visual vertical (SVV) measures the perception of a person's spatial orientation relative to gravity. Weighted central integration of vestibular, visual, and proprioceptive inputs is essential for SVV perception. Without any visual references and minimal proprioceptive contribution, the static SVV reflects balance of the otolith organs. Normal aging is associated with bilateral and progressive decline in otolith organ function, but age-dependent effects on SVV are inconclusive. Studies on sensory reweighting for visual vertical and multisensory integration strategies reveal age-dependent differences, but most studies have included elderly participants in comparison to younger adults. The aim of this study was to compare young adults with older adults, an age group younger than the elderly. METHODS: Thirty-three young and 28 older adults (50-65 years old) adjusted a tilted line accurately to their perceived vertical. The rod's final position from true vertical was recorded as tilt error in degrees. For otolithic balance, visual vertical was recorded in the dark without any visual references. The rod and frame task (RFT) with tilted disorienting visual frames was used for creating visuovestibular conflict. We adopted Nyborg's analysis method to derive the rod and frame effect (RFE) and trial-to-trial variability measures. Rod alignment times were also analyzed. RESULTS: There was no age difference in signed tilts of SVV without visual reference. There was an age effect on RFE and on overall trial-to-trial variability of rod tilt, with older adults displaying larger frame effects and greater variability in rod tilts. Alignment times were longer in the tilted-frame conditions for both groups and in the older adults compared to their younger counterparts. The association between tilt accuracy and tilt precision was significant for older adults only during visuovestibular conflict, revealing an increase in RFE with an increase in tilt variability. Correlation of σ SVV, which represents vestibular input precision, with RFE yielded exactly the same contribution of σ SVV to the variance in RFE for both age groups. CONCLUSIONS: Older adults have balanced otolithic input in an upright position. Increased reliance on visual cues may begin at ages younger than what is considered elderly. Increased alignment times for older adults may create a broader time window for integration of relevant and irrelevant sensory information, thus enhancing their multisensory integration. In parallel with the elderly, older adults may differ from young adults in their integration of sensory cues for visual vertical perception.

High-normal blood glucose levels may be associated with decreased spatial perception in young healthy adults.

The negative effects of high normal glucose on cognitive function were previously reported in euglycemic individuals of middle age and the elderly population. This study aimed at examining the effect of baseline blood glucose levels on spatial ability, specifically verticality perception on the computerized rod and frame test (CRFT) in young healthy adults. 63 healthy male medical students (age range from 18-23 years), of whom 30 were non-fasting outside the month of Ramadan and 33 fasting during Ramadan of the year 2016, were recruited in order to create varying degrees of glycemia during which verticality perception was carried out. Baseline blood glucose reading was obtained prior to commencing the CRFT test. Blood glucose levels at the time of testing decreased as the duration between the last meal and testing increased. A blood glucose range of 62-117 mg/dl was achieved among participants for this study. Linear regression analysis showed that blood glucose level at testing correlated positively with all alignment spatial error parameters, indicating a probable reduction of spatial perception ability with higher blood glucose levels. These results are consistent with other cognitive studies in older healthy humans and emphasize the critical impact of early glucose dys-homeostasis on cognitive function. They also indicate that elevated blood glucose may affect cognitive functioning outside of the usual complications of diabetes.

The immediate effect of multiple mechanical impulses on electromyography and pressure pain threshold of lumbar latent trigger points: an experimental study.

BACKGROUND: Myofascial pain is a common syndrome, which has not been studied extensively in the low back. Despite a variety of manual and instrument assisted interventions available, little work has targeted the possible effects of fast mechanical impulses on myofascial trigger points (MTrPs) on its sensitivity and electrical activity. The purpose of this experimental study was to quantify the immediate effect of one session of mechanical impulses to lumbar latent MTrPs and to normal muscle tissue with pressure pain threshold (PPT) and surface electromyography (sEMG) as outcome measures. METHODS: During the autumn of 2009, in 41 asymptomatic subjects between 17-40 years of age the lumbar musculature was searched for a latent MTrP by a trained clinician. Using 3 disposable pre-gelled electrodes bilaterally, sEMG was recorded continuously from muscle containing either latent or no MTrP. Both the trigger point group and control group received the intervention and were blinded to group allocation. The immediate effects of mechanical impulses were assessed by sEMG and PPT before and after intervention using Wilcoxon matched-pairs signed-ranks test, Mann-Whitney U test and paired t-tests. RESULTS: The PPT increased significantly across both groups (p < 0.01) after intervention. The proportionate increase (14.6 %) was comparable in both MTrP and control groups. The electrical activity on the MTrP side was not significantly higher in the MTrP group compared to the contralateral side. The decrease of resting electrical activity after intervention was significant in the MTrP group on the side of the latent MTrP (P = 0.001) as well as the contralateral side (p=0.022), and not significant in the control group on either side (p=0.33 and p=0.93). CONCLUSION: In this study, the immediate effect of one session of mechanical impulses was associated with a significant increase in PPT for both groups and a significant decrease in the resting electrical activity of the lumbar muscles only in the MTrP group. It is unknown if these effects have clinical significance.

Effects of nociceptin and analogues of nociceptin upon spontaneous dorsal root activity recorded from an in vitro preparation of rat spinal cord.

The 17 amino acid peptide nociceptin has been implicated in pain modulation in the central nervous system. The effects of bath applied nociceptin, and some analogues of nociceptin, upon spontaneous lumbar dorsal root activity have been investigated in an isolated preparation of rat spinal cord. Nociceptin was found to reversibly depress spontaneous dorsal root activity at concentrations of 1.0 microM and 10.0 microM (IC50 2.0 microM), whereas acetyl-nociceptin at concentrations up to 10 microM had no detectable effect. Omission of the last four amino acids (nociceptin 1-13), increased the potency of the effect upon dorsal root activity by approximately 100-fold (IC50 30 nM), but activity was lost when only the first seven amino acids of the nociceptin molecule (nociceptin 1-7) were tested.

Changes in rod and frame test scores recorded in schoolchildren during development--a longitudinal study.

The Rod and Frame Test has been used to assess the degree to which subjects rely on the visual frame of reference to perceive vertical (visual field dependence-independence perceptual style). Early investigations found children exhibited a wide range of alignment errors, which reduced as they matured. These studies used a mechanical Rod and Frame system, and presented only mean values of grouped data. The current study also considered changes in individual performance. Changes in rod alignment accuracy in 419 school children were measured using a computer-based Rod and Frame test. Each child was tested at school Grade 2 and retested in Grades 4 and 6. The results confirmed that children displayed a wide range of alignment errors, which decreased with age but did not reach the expected adult values. Although most children showed a decrease in frame dependency over the 4 years of the study, almost 20% had increased alignment errors suggesting that they were becoming more frame-dependent. Plots of individual variation (SD) against mean error allowed the sample to be divided into 4 groups; the majority with small errors and SDs; a group with small SDs, but alignments clustering around the frame angle of 18°; a group showing large errors in the opposite direction to the frame tilt; and a small number with large SDs whose alignment appeared to be random. The errors in the last 3 groups could largely be explained by alignment of the rod to different aspects of the frame. At corresponding ages females exhibited larger alignment errors than males although this did not reach statistical significance. This study confirms that children rely more heavily on the visual frame of reference for processing spatial orientation cues. Most become less frame-dependent as they mature, but there are considerable individual differences.

Inspiratory conductance: an alternative index of the relationship between inspiratory effort and airflow with potential for clinical use.

INTRODUCTION AND OBJECTIVES: There is a need for a measure of airway status that is easier for patients to use. If airflow is briefly occluded at the onset of inspiration, the maximum rate of pressure fall, dP/dtmax can be measured. After the occlusion is released, the maximum rate of change of inspiratory airflow (dF/dtmax) can be measured and expressed as a ratio of dP/dtmax to generate an index of inspiratory conductance (IC). We explored the characteristics of IC as a preliminary step towards developing it as an easy-to-use alternative. METHODS: To measure IC, we constructed an apparatus consisting of a pneumotachograph, a low-resistance spring-loaded valve and a pressure transducer to measure airflow and pressure drop at the start of inspiration. We studied 30 healthy adults to define the values of the index, its stability and its response to external inspiratory resistive loads. RESULTS: Mean IC was 2.49 (SD 0.96) Ls(-1) kPa(-1) , with no significant difference between men and women. The index was stable with a mean long-term variation of 11.25% around the normalised mean, compared with 2.1% for forced expiratory volume in 1 s (FEV1) and within-test variation < 5%. In response to external resistive loading, IC fell in a non-linear but consistent manner from 3.96 (0.32) to 0.96 (0.10) Ls(-1) kPa(-1) across an added resistance range of 0-70 kPasL(-1) . CONCLUSION: We showed that IC was measurable with a minimal need for subject participation. It was stable and reproducible in normal individuals and responded to added inspiratory resistive loads in a way that suggested it could be of clinical utility.

Perception of subjective visual vertical and horizontal in patients with chronic neck pain: a cross-sectional observational study.

Previous studies have shown that chronic neck pain (CNP) patients have a larger spread of perceptual errors for subjective visual vertical (SVV) than those exhibited by asymptomatic controls. The current study investigated whether this was also the case for perception of subjective visual horizontal (SVH) and whether there was a correlation between the two measurements. Fifty patients with CNP were compared with a group of 50 age- and gender-matched controls. All subjects were required to complete a test to measure SVH as well as SVV using the computerised rod and frame (CRAF) test. These tests were conducted under various frame conditions. No difference was found between the errors of the CNP and control groups in the absence of a surrounding frame. When a tilted frame was added to the CRAF test, the range of errors observed in the CNP group increased for both SVV and SVH. In particular, significantly more CNP patients fell outside the reference range of errors and a subgroup of patients, characterised by higher neck pain disability indices, was identified who demonstrated higher than expected errors for both SVV and SVH. However no conclusion could be drawn with regards to the direction of error asymmetry and laterality of pain as those patients with unilateral pain exhibited errors both towards and away from the affected area.

Subjective visual vertical perception and sense of smell in Parkinson disease.

This article describes an open cross-sectional observational study involving 47 participants with Parkinson disease (PD) and 47 (age- and sex-matched) nondisabled controls without PD. The aim was to determine the profiles of subjective visual vertical (SVV) perception and sense of smell perception in both groups. There was a statistically significant difference (p < 0.001) between patients and controls on their smell test performance. Controls were more likely to correctly identify odors, with a median score of 10 out of 12 compared with 6.5 out of 12 for patients with PD. The median SVV error for the PD group when the frame was untilted was 0.75 degrees compared with 0.50 degrees for controls. This difference was statistically significant (p = 0.02). When the frame was tilted, the median SVV error for the PD group was 2.31 degrees compared with 2.00 degrees for controls (not statistically significant), with both groups showing similar distribution pattern of errors. There was no statistical correlation between number of correctly identified odors and an individual's SVV error. However, a statistically significant negative correlation (r = -0.45, p = 0.01) was found between Mini-Mental State Examination score and mean time taken to complete each rod and frame test in patients with PD, suggesting that SVV errors might be more correlated with cognitive function than with loss of sense of smell.

From line to dots: an improved computerised rod and frame system for testing subjective visual vertical and horizontal.

BACKGROUND: Perception of subjective visual vertical (SVV) and horizontal (SVH) has traditionally been measured by rotating a mechanical rod either with or without a frame present. The computerised rod and frame (CRAF) system has previously only been used to measure SVV. We have expanded the use of this system by testing its feasibility to measure SVH. This was done by comparing two groups of subjects (n = 103) randomly assigned to be tested for SVV or SVH. FINDINGS: Preliminary results showed a higher than expected percentage of individuals with SVH errors < 0.5 degrees . This was attributed to additional visual cues provided by the changing appearance of the rod as it approached the horizontal. A solution to this problem was sought by replacing the rod by two dots to mark its ends. In a second investigation 30 subjects were tested using both the "rod as line" and "rod as dots" presentation. Bland and Altman analysis showed no difference between the rod and dots presentations in the measurement of SVV, but confirmed a fixed error of -0.93 degrees between rods and dots for SVH. Changing the rod from a line to dots in the computer system resulted in errors for both SVV and SVH that were comparable to previous studies using manual systems. CONCLUSIONS: The computerized rod and frame system may be improved by replacement of the line with two dots. This reduces clues provided to the subject by the appearance of the rod on the screen.

Midlumbar lateral flexion stability measured in healthy volunteers by in vivo fluoroscopy.

STUDY DESIGN: Prospective fluoroscopic and electromyographic study of coronal plane lumbar spine motion in healthy male volunteers. OBJECTIVES: Assess the intervertebral motion profiles in healthy volunteers for symmetry, regularity, and neutral zone laxity during passive recumbent lateral bending motion. SUMMARY OF BACKGROUND DATA: Previous continuous in vivo motion studies of the lumbar spine have mainly been limited to active, weight-bearing, flexion-extension (sagittal plane) motion. No data are available for passive lateral bending or to indicate the motion profiles when muscle activity is minimized. METHODS: Thirty asymptomatic male volunteers underwent video-fluoroscopy of their lumbar spines during passive, recumbent lumbar lateral bending through 80 degrees using a motor-driven motion table. Approximately 120 consecutive images of segments L2-L5 were captured, and the position of each vertebra was tracked throughout the sequence using automated frame-to-frame registration. Reference intervals for intervertebral motion parameters were calculated. Surface electromyography recordings of erector spinae were obtained in a similar group of volunteers using the same protocol without fluoroscopy to determine to what extent the motion was completely passive. RESULTS: Correlations between intervertebral and lumbar motion were always positive in controls and asymmetry was less than 55% of intervertebral range. The upper reference interval for the slope of intervertebral rotation in the first 10 degrees of trunk motion did not exceed 0.46 for any level. Muscle electrical activity during the motion was very low. Examples from patient studies showed markedly different results. CONCLUSION: These results suggest that reference limits from asymptomatic data for coronal plane passive recumbent intervertebral motion may be a useful resource for investigating the relationship between symptoms of chronic (nonspecific) low back pain and biomechanics and in the clinical assessment of patients and interventions that target the passive holding elements of the spine. Data pooling from multiple studies would be necessary to establish a complete database.

Effects of amino acid antagonists on spontaneous dorsal root activity and evoked dorsal horn field potentials in an isolated preparation of rat spinal cord.

Fast and slow dorsal horn field potentials and spontaneous dorsal root activity were recorded from 19-23-day-old rat isolated spinal cord preparations. The effects of GABA, glycine, and glutamate antagonists were tested on these recordings. CNQX, an AMPA/kainate antagonist, reduced all 3 components of the dorsal horn field potential whereas MK801, an NMDA ion channel antagonist, reduced the fast S2 component and the slow wave. Both reduced spontaneous dorsal root activity. NMDA antagonists, D-AP5, 7-chlorokynurenic acid and arcaine, and the metabotropic glutamate antagonists L-AP3 and ethylglutamic acid, while having little effect on the fast components of the field potential, all reduced the slow component. The GABA antagonist, bicuculline, and the glycine antagonist, strychnine, while having no effect on the fast S1 and slow components of the field potential, reduced both the fast S2 component of the field potential and spontaneous dorsal root activity. These results suggest that non-NMDA glutamate receptors are involved in low and high threshold transmission to dorsal horn neurones while NMDA and metabotropic glutamate receptors are primarily involved in high threshold transmission and both GABA and glycine have roles in the transmission or modulation of sensory information within the dorsal horn of the cord.

Assessment of verticality perception by a rod-and-frame test: preliminary observations on the use of a computer monitor and video eye glasses.

A computer-based version of the rod-and-frame test for verticality perception has been developed. The task tested verticality perception of subjects by using the computer mouse to rotate a bright rod to a vertical orientation within a square frame that was tilted through a range of angles from 30 degrees counterclockwise to 30 degrees clockwise. In 16 healthy subjects, errors from the true vertical were generated in the direction of the frame tilt. The errors reached statistical significance ( P <.05) when the frame was rotated by 10 degrees in either direction. In a second study, the images were presented to the subjects who wore a pair of video eyeglasses. The pattern of errors generated by rotation of the frame were similar but were of larger amplitude than those produced in the first experiment and reached statistical significance with frame angles of 10 degrees and 20 degrees in both directions. These preliminary investigations suggest that the computer-based rod-and-frame test may provide a more convenient alternative to the mechanical rod-and-frame test for verticality perception.