Biomedical subjects

Roberta L Klatzky

Publications and source records attributed to Roberta L Klatzky.

At least 19 recordsLinked to original sources

PubMed2026

Improving Patient Comfort of Vibratory Anesthetic Devices With a Dampener: A Pilot Study.

BACKGROUND: Vibratory anesthetic devices (VADs) reduce dermatologic injection pain, but their vibration can feel harsh at sensitive anatomical sites. Simple modifications improving patient comfort may enhance VAD adoption. OBJECTIVE: The authors evaluated whether dampening VAD vibration with a cotton buffer improves patient comfort and characterized tactile features influencing preferences. MATERIALS AND METHODS: In a single-site, participant-blinded pilot study (N = 53), adults received a dampened VAD (D-VAD) and standard VAD (S-VAD) at 5 sites-lateral nasal wall, submalar cheek, ear helix, lateral neck, and dorsal forearm-in randomized, contralateral application. Site-specific preference was analyzed with binomial and Cochran Q tests; demographic associations with univariate analyses. Word2vec and hierarchical clustering analyzed qualitative reasons behind patient preference. RESULTS: D-VAD was preferred at all sites across demographics-lateral nasal wall (88.7%), submalar cheek (84.9%), ear helix (88.7%), lateral neck (77.4%), and dorsal forearm (75.5%) (all p < .001), with strongest preference at face and head/neck (p = .018). Computational semantics analysis of qualitative responses identified 6 themes driving preference: Smoothness, Gentleness, Controlled, Low Frequency, Low Intensity, and Less Bothersome. CONCLUSION: Dampening VAD vibration with a cotton buffer enhances comfort across sensitive sites, with reduced harshness and smoother sensation underlying preference. This simple modification may improve patient experience, encouraging broader VAD adoption.

Humans↗

PubMed2006

Cognitive load of navigating without vision when guided by virtual sound versus spatial language.

A vibrotactile N-back task was used to generate cognitive load while participants were guided along virtual paths without vision. As participants stepped in place, they moved along a virtual path of linear segments. Information was provided en route about the direction of the next turning point, by spatial language ("left," "right," or "straight") or virtual sound (i.e., the perceived azimuth of the sound indicated the target direction). The authors hypothesized that virtual sound, being processed at direct perceptual levels, would have lower load than even simple language commands, which require cognitive mediation. As predicted, whereas the guidance modes did not differ significantly in the no-load condition, participants showed shorter distance traveled and less time to complete a path when performing the N-back task while navigating with virtual sound as guidance. Virtual sound also produced better N-back performance than spatial language. By indicating the superiority of virtual sound for guidance when cognitive load is present, as is characteristic of everyday navigation, these results have implications for guidance systems for the visually impaired and others.

Adult↗

PubMed2006

Vascular access: comparison of US guidance with the sonic flashlight and conventional US in phantoms.

PURPOSE: To prospectively evaluate whether ultrasonography (US)-guided vascular access can be learned and performed faster with the sonic flashlight than with conventional US and to demonstrate sonic flashlight-guided vascular access in a cadaver. MATERIALS AND METHODS: Institutional review board approval and oral and written informed consent were obtained. The sonic flashlight replaces the standard US monitor with a real-time US image that appears to float beneath the skin and is displayed where it is scanned. In studies 1 and 2, participants performed sonic flashlight-guided needle insertion tasks in vascular phantoms. In study 1, 16 participants (nine women, seven men) with no US experience performed 60 simulated vascular access trials with sonic flashlight or conventional US guidance. With analysis of variance (ANOVA) and power-curve fitting, improvement with practice rate and mean differences between techniques and tasks were examined. In study 2, 14 female nurses (mean age, 50.1 years) proficient with conventional US performed simulated vascular access trials on three tasks with the sonic flashlight and conventional US. With random assignment, half the participants used the sonic flashlight first and half used conventional US first. Mean performance with each technique and that with each task were compared by using ANOVA. In study 3, feasibility of sonic flashlight guidance for access to internal jugular and basilic veins was demonstrated in a cadaver. RESULTS: For study 1, learning rates (ie, decrease in access time over trials) did not differ for vascular access with sonic flashlight and conventional US. Overall, participants achieved faster vascular access times with sonic flashlight guidance (P < .007). In study 2, participants performed procedures faster overall with the sonic flashlight (P < .02) and found the sonic flashlight easier to use. In study 3, sonic flashlight-guided vascular access was gained in the cadaver. CONCLUSION: Learning and performance of vascular access were significantly faster with the sonic flashlight than with conventional US, and vascular access could be gained in a cadaver; the sonic flashlight is ready for clinical trials.

Adult↗

PubMed2005

What vs. where in touch: an fMRI study.

Two streams have been identified in cortical visual processing: a ventral stream for form, color, and features, and a dorsal stream for spatial characteristics and motion. We investigated whether similar "what" and "where" dissociations of function exist for human somatosensory processing. Using identical stimuli and hand movements, subjects either performed tactile object recognition (TOR) and ignored location or performed tactile object localization (LOC) and ignored identity. A matched-movement control task separated activation associated with sensorimotor input from higher-level cognitive contributions. Results confirmed separate processing streams for TOR and LOC. TOR activated the frontal pole as well as bilateral inferior parietal and left prefrontal regions involved in tactile feature integration and naming. LOC activated bilateral superior parietal areas involved in spatial processing. The dissociation of object and spatial processing streams appears to be a modality general organizational principle in the brain.

Adult↗

PubMed2005

Imagining material versus geometric properties of objects: an fMRI study.

Two experiments are reported that used fMRI to compare the brain activation during the imagery of material and geometric object features. In the first experiment, participants were to mentally evaluate objects along either a material dimension (roughness, hardness and temperature; e.g., Which is harder, a potato or a mushroom?) or a geometric dimension (size and shape; e.g., Which is larger, a pumpkin or a cucumber?). In the second experiment, when given the name of an object and either a material (roughness and hardness) or geometric (size and shape) property participants rated the object on a scale from 1 to 4. Both experiments were designed to examine the underlying neural substrate that supports the processing of material object properties with respect to geometric properties. Considering the relative amount of activation across the two types of object properties, we found that (1) the interrogation of geometric features differentially evokes visual imagery which involves the region in and around the intraparietal sulcus, (2) the interrogation of material features differentially evokes the processing of semantic object representations which involves the inferior extrastriate region, and (3) the lateral occipital cortex (LOC) responds to shape processing regardless of whether the feature being queried is a material or geometric feature.

Adult↗

PubMed2005

Perceptual limits for a robotic rehabilitation environment using visual feedback distortion.

Imperceptible visual distortion, in the form of a disguised progression of performance goals, may be a helpful addition to rehabilitation after stroke and other brain injuries. This paper describes work that has been done to lay the groundwork for testing this hypothesis. We have constructed and validated an experimental environment that provides controllable visual distortion and allows precise force and position measurements. To estimate the amount of visual distortion that should be imperceptible, we measured the limits for force and distance/position perception in our rehabilitation environment for young and elderly unimpaired subjects and for a single traumatic brain injury (TBI) patient. We found the Just Noticeable Difference (JND) for produced force to be 19.7% (0.296 N) and the JND for movement distance/finger position to be 13.0% (3.99 mm) for young subjects (ages 18-35). For elderly subjects (ages 61-80), the JND for force was measured to be 31.0% (0.619 N) and the JND for distance/po'sition was 16.1% (5.01 mm). JNDs of 46.0% (0.920 N) and 45.0% (14.8 mm) were found for the motor-impaired individual. In addition, a subject's rating of effort was found to be profoundly influenced by visual feedback concerning the force magnitude. Even when this feedback was distorted, it accounted for 99% of the variance of the effort rating. These results indicate that substantial visual distortions should be imperceptible to the subject, and that visual feedback can be used to influence the subject's perceived experience in our robotic environment. This means that we should be able to use imperceptible visual distortion to alter a patient's perception of therapeutic exercise in a robotic environment.

Adolescent↗

PubMed2004

Functional equivalence of spatial representations derived from vision and language: evidence from allocentric judgments.

Past research (e.g., J. M. Loomis, Y. Lippa, R. L. Klatzky, & R. G. Golledge, 2002) has indicated that spatial representations derived from spatial language can function equivalently to those derived from perception. The authors tested functional equivalence for reporting spatial relations that were not explicitly stated during learning. Participants learned a spatial layout by visual perception or spatial language and then made allocentric direction and distance judgments. Experiments 1 and 2 indicated allocentric relations could be accurately reported in all modalities, but visually perceived layouts, tested with or without vision, produced faster and less variable directional responses than language. In Experiment 3, when participants were forced to create a spatial image during learning (by spatially updating during a backward translation), functional equivalence of spatial language and visual perception was demonstrated by patterns of latency, systematic error, and variability.

Female↗

PubMed2004

Haptic processing of the location of a known property: does knowing what you've touched tell you where it is?

The relationship between knowing where a haptic property is located and knowing what it is was investigated using a haptic-search paradigm. Across trials, from one to six stimuli were presented simultaneously to varying combinations of the middle three fingertips of both hands. Participants reported the presence/absence of a target or its location for four perceptual dimensions: rough/smooth, edge/no edge, relative position (right/left), and relative orientation (right/left). Reaction time data were plotted as a function of set size. The slope data indicated no difference in processing load for location as compared to identity processing. However, the intercept data did reveal a cost associated with processing location information. Location information was not obtained for "free" when identity was processed. The data also supported a critical distinction between material and edge dimensions versus geometric dimensions, as the size of the cost associated with processing location was larger for spatial than for intensive stimuli.

Adolescent↗

PubMed2004

Use of cognitive versus perceptual heading during imagined locomotion depends on the response mode.

Three experiments investigated whether the systematic errors previously observed in a triangle-completion task were caused by failures to form and update a cognitive heading or by use of perceived heading (even though an updated cognitive heading was available) during the response. These errors were replicated when participants indicated the origin of triangular paths they had imagined walking by turning their bodies toward the origin, but not when they responded verbally. The results indicate that participants are capable of updating their cognitive heading using imagined movements and suggest that the systematic errors previously observed were a result of the strong attachment of responses such as turns to a perceptual representation of the physical body.

Cognition↗

PubMed2004

Haptic identification of common objects: effects of constraining the manual exploration process.

In this article, we address the effects on haptic recognition of common objects when manual exploration is constrained by using two kinds of rigid links--sheaths (Experiment 1A) and probes (Experiments 1B and 2). The collective effects of five different constraints are considered, including three from previous research (i.e., reducing the number of end effectors, wearing a compliant finger cover, and splinting the fingers; Klatzky, Loomis, Lederman, Wake, & Fujita, 1993) and from two current constraints (i.e., wearing a rigid finger sheath and using a rigid probe). The resulting impairments are interpreted in terms of the loss of somatosensory information from cutaneous and/or kinesthetic inputs. In addition, we relate the results to the design of haptic interfaces for teleoperation and virtual environments, which share some of the same reduction of sensory cues that we have produced experimentally.

Fingers↗

PubMed2003

Representing spatial location and layout from sparse kinesthetic contacts.

Participants' fingers were guided to 2 locations on a table for 3 s, then back to the start. They reported distances and angles between the locations by (a) replacing 1 or 2 fingers, (b) translating the contacted configuration, or (c) estimating distance or angle alone. Distance error increased across these conditions. Angular error increased when the angular reference axis was rotated before the response. Replacing 1 finger was impaired by a change in posture from exposure to test. The results suggest a kinesthetic representation is used to replace the fingers, but to estimate distance and angle at new locations, a configural representation is computed. This presentation is oriented within an extrinsic reference frame and maintains shape more accurately than scale.

Adult↗

PubMed2003

Watching a cursor distorts haptically guided reproduction of mouse movement.

Participants moved a mouse along a force-feedback-defined linear path, either without vision or while watching a cursor set to 1 of 3 levels of visual:haptic gain (all >1:1). They attempted to haptically reproduce the movement without visual feedback. Errors increased with gain, reaching 70% overestimation at the highest gain. Forewarning participants about gain variability did not eliminate this effect. The gain level was potentially cued during the movement by the mismatch between visual feedback and kinesthetic feedback. Moreover, because participants did not achieve cursor-speed constancy across gain levels, visual speed was another cue to gain. Collectively, these cues failed to prevent visual distortion of movement reproduction.

Attention↗

PubMed2003

Feeling textures through a probe: effects of probe and surface geometry and exploratory factors.

Vibratory roughness perception occurs when people feel a surface with a rigid probe. Accordingly, perceived roughness should reflect probe and surface geometry, exploratory speed, and force. Experiments 1 and 2 compared magnitude estimation of roughness with the bare finger and two types of probes, one designed to eliminate force moments, under the subject's active control. Experiments 3 and 4 varied speed under passive control. Log magnitude was consistently a quadratic function of log spacing between elements in the surface. The location of the function's peak was related to the drop point--that is, the spacing at which the probe can just drop between elements--which is affected by probe tip diameter, element height, and speed. Other parameters of the quadratic were affected by probe type and speed.

Female↗

PubMed2002

Encoding, learning, and spatial updating of multiple object locations specified by 3-D sound, spatial language, and vision.

Participants standing at an origin learned the distance and azimuth of target objects that were specified by 3-D sound, spatial language, or vision. We tested whether the ensuing target representations functioned equivalently across modalities for purposes of spatial updating. In experiment 1, participants localized targets by pointing to each and verbalizing its distance, both directly from the origin and at an indirect waypoint. In experiment 2, participants localized targets by walking to each directly from the origin and via an indirect waypoint. Spatial updating bias was estimated by the spatial-coordinate difference between indirect and direct localization; noise from updating was estimated by the difference in variability of localization. Learning rate and noise favored vision over the two auditory modalities. For all modalities, bias during updating tended to move targets forward, comparably so for three and five targets and for forward and rightward indirect-walking directions. Spatial language produced additional updating bias and noise from updating. Although spatial representations formed from language afford updating, they do not function entirely equivalently to those from intrinsically spatial modalities.

Adult↗

PubMed2002

The tolerance for visual feedback distortions in a virtual environment.

We are interested in using a virtual environment with a robotic device to extend the strength and mobility of people recovering from strokes by steering them beyond what they had thought they were capable of doing. Previously, we identified just noticeable differences (JND) of a finger's force production and position displacement in a virtual environment. In this paper, we extend this investigation by identifying peoples' tolerance for distortions of visual representations of force production and positional displacement in a virtual environment. We determined that subjects are not capable of reliably detecting inaccuracies in visual representation until there is 36% distortion. This discrepancy between actual and perceived movements is significantly larger than the JNDs reported in the past, indicating that a virtual robotic environment could be a valuable tool for steering actual movements further away from perceived movements. We believe this distorted condition may allow people recovering from strokes, even those who have perceptual or cognitive deficits, to rehabilitate with greater ease.

Adult↗

PubMed2002

Spatial updating of locations specified by 3-d sound and spatial language.

Blind and blindfolded sighted observers were presented with auditory stimuli specifying target locations. The stimulus was either sound from a loudspeaker or spatial language (e.g., "2 o'clock, 16 ft"). On each trial, an observer attempted to walk to the target location along a direct or indirect path. The ability to mentally keep track of the target location without concurrent perceptual information about it (spatial updating) was assessed in terms of the separation between the stopping points for the 2 paths. Updating performance was very nearly the same for the 2 modalities, indicating that once an internal representation of a location has been determined, subsequent updating performance is nearly independent of the modality used to specify the representation.

Adult↗

PubMed2002

The phonological-similarity effect differentiates between two working memory tasks.

Working memory is a set of interactive cognitive processes that maintain information on-line and available for analysis. Part of the system is specialized for maintaining verbal information, a core component of which is thought to be a phonological store. On the basis of the study of patients with acquired brain lesions, this store has been localized to the supramarginal and angular gyri of the speech-dominant hemisphere, and some functional neuroimaging studies support this localization. However, other imaging studies localize the phonological store in a more dorsal region of the parietal lobe. To reconcile these findings, we examined the phonological-similarity effect in two different tasks. A phonological-similarity effect was observed only in the task that involved sequential presentation and explicit verbal rehearsal. We conclude that at least one possible source of the differences in brain activation between different working memory tasks may be differences in phonological processing.

Adult↗

PubMedDate not supplied

Learning directions of objects specified by vision, spatial audition, or auditory spatial language.

The modality by which object azimuths (directions) are presented affects learning of multiple locations. In Experiment 1, participants learned sets of three and five object azimuths specified by a visual virtual environment, spatial audition (3D sound), or auditory spatial language. Five azimuths were learned faster when specified by spatial modalities (vision, audition) than by language. Experiment 2 equated the modalities for proprioceptive cues and eliminated spatial cues unique to vision (optic flow) and audition (differential binaural signals). There remained a learning disadvantage for spatial language. We attribute this result to the cost of indirect processing from words to spatial representations.

Adult↗