John-Ross Rizzo

Dr. John-Ross Rizzo


Research Focus & Metrics

Academic Career Length

27Years (2000-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 August 2017 in Journal of Vision
Verified
Journal Article
Open access
PDF file
WDWeiwei Dai
Weiwei Dai
ISIvan Selesnick
Ivan Selesnick
JRJohn-Ross Rizzo
John-Ross Rizzo
JRJanet C Rucker
Janet C Rucker
THTodd Hudson
Todd Hudson
The Savitzky-Golay (SG) filter is widely used to smooth and differentiate time series, especially biomedical data. However, time series that exhibit abrupt departures from their typical trends, such as sharp waves or steps, which are of physiological interest, tend to be oversmoothed by the SG filter. Hence, the SG filter tends to systematically underestimate physiological parameters in certain situations. This article proposes a generalization of the SG filter to more accurately track abrupt deviations in time series, leading to more accurate parameter estimates (e.g., peak velocity of saccadic eye movements). The proposed filtering methodology models a time series as the sum of two component time series: a low-frequency time series for which the conventional SG filter is well suited, and a second time series that exhibits instantaneous deviations (e.g., sharp waves, steps, or more generally, discontinuities in a higher order derivative). The generalized SG filter is then applied to the quantitative analysis of saccadic eye movements. It is demonstrated that (a) the conventional SG filter underestimates the peak velocity of saccades, especially those of small amplitude, and (b) the generalized SG filter estimates peak saccadic velocity more accurately than the conventional filter.

1 September 2016 in Annals of Clinical and Translational Neurology
Verified
Journal Article
Open access
PDF file
JRJohn-Ross Rizzo
John-Ross Rizzo
THTodd E. Hudson
Todd E. Hudson
WDWeiwei Dai
Weiwei Dai
JBJoel Birkemeier
Joel Birkemeier
RPRosa M. Pasculli
Rosa M. Pasculli
JRJanet C Rucker
Janet C Rucker
Objective: The King–Devick (KD) test, which is based on rapid number naming speed, is a performance measure that adds vision and eye movement assessments to sideline concussion testing. We performed a laboratory‐based study to characterize ocular motor behavior during the KD test in a patient cohort with chronic concussion to identify features associated with prolonged KD reading times.Methods: Twenty‐five patients with a concussion history (mean age: 31) were compared to control participants with no concussion history (n = 42, mean age: 32). Participants performed a computerized KD test under infrared‐based video‐oculography.Results: Average intersaccadic intervals for task‐specific saccades were significantly longer among concussed patients compared to controls (324.4 ± 85.6 msec vs. 286.1 ± 49.7 msec, P = 0.027). Digitized KD reading times were prolonged in concussed participants versus controls (53.43 ± 14.04 sec vs. 43.80 ± 8.55 sec, P = 0.004) and were highly correlated with intersaccadic intervals. Concussion was also associated with a greater number of saccades during number reading and larger average deviations of saccade endpoint distances from the centers of the to‐be‐read numbers (1.22 ± 0.29° vs. 0.98 ± 0.27°, P = 0.002). There were no differences in saccade peak velocity, duration, or amplitude.Interpretation: Prolonged intersaccadic intervals, greater numbers of saccades, and larger deviations of saccade endpoints underlie prolonged KD reading times in chronic concussion. The KD test relies upon a diffuse neurocognitive network that mediates the fine control of efferent visual function. One sequela of chronic concussion may be disruption of this system, which may produce deficits in spatial target selection and planning of eye movements.

18 December 2015 in Journal of Medicinal Chemistry
Verified
Journal Article
Closed access
MSMatthew A. Schiffler
Matthew A. Schiffler
SAStephen Antonysamy
Stephen Antonysamy
SBShobha N. Bhattachar
Shobha N. Bhattachar
KCKristina M. Campanale
Kristina M. Campanale
SCSrinivasan Chandrasekhar
Srinivasan Chandrasekhar
XYXiao-Peng Yu
Xiao-Peng Yu

1 March 2016 in Journal of the Neurological Sciences
Verified
Journal Article
Closed access
JRJohn-Ross Rizzo
John-Ross Rizzo
THTodd E. Hudson
Todd E. Hudson
WDWeiwei Dai
Weiwei Dai
NDNinad Desai
Ninad Desai
AYArash Yousefi
Arash Yousefi
JRJanet C Rucker
Janet C Rucker

1 June 2017 in Frontiers in Neurology
Verified
Journal Article
Open access
JRJohn-Ross Rizzo
John-Ross Rizzo
MHMaryam Hosseini
Maryam Hosseini
EWEric A. Wong
Eric A. Wong
WMWayne E. Mackey
Wayne E. Mackey
JFJames K. Fung
James K. Fung
THTodd E. Hudson
Todd E. Hudson
Acute and chronic disease processes that lead to cerebral injury can often be clinically challenging diagnostically, prognostically, and therapeutically. Neurodegenerative processes are one such elusive diagnostic group, given their often diffuse and indolent nature, creating difficulties in pinpointing specific structural abnormalities that relate to functional limitations. A number of studies in recent years have focused on eye-hand coordination in the setting of acquired brain injury (ABI), highlighting the important set of interconnected functions of the eye and hand and their relevance in neurological conditions. These experiments, which have concentrated on focal lesion-based models, have significantly improved our understanding of neurophysiology and underscored the sensitivity of biomarkers in acute and chronic neurological disease processes, especially when such biomarkers are combined synergistically. To better understand eye-hand coordination and its connection with ABI, there is a need to clarify its definition and to delineate its neuroanatomical and computational underpinnings. Successful eye-hand coordination relies on the complex feedback- and prediction-mediated relationship between the visual, ocular-motor, and manual motor systems and takes advantage of finely orchestrated synergies between these systems in both the spatial and temporal domains. Interactions of this type are representative of functional sensory-motor control, and whose disruption constitutes one of the most frequent deficits secondary to brain injury. The present review describes the visually mediated planning and control of eye movements, hand movements, and their coordination, with a particular focus on deficits that occur following neurovascular, neurotraumatic, and neurodegenerative conditions. Following this review, we also discuss potential future research directions, highlighting objective eye-hand coordination as a sensitive biomarker complement within acute and chronic neurological disease processes.

26 April 2024 in Journal of Imaging
Verified
Journal Article
Open access
PDF file
YHYu Hao
Yu Hao
FYFan Yang
Fan Yang
HHHao Huang
Hao Huang
SYShuaihang Yuan
Shuaihang Yuan
SRSundeep Rangan
Sundeep Rangan
Yi FangYi Fang
Yi Fang
People with blindness and low vision (pBLV) encounter substantial challenges when it comes to comprehensive scene recognition and precise object identification in unfamiliar environments. Additionally, due to the vision loss, pBLV have difficulty in accessing and identifying potential tripping hazards independently. Previous assistive technologies for the visually impaired often struggle in real-world scenarios due to the need for constant training and lack of robustness, which limits their effectiveness, especially in dynamic and unfamiliar environments, where accurate and efficient perception is crucial. Therefore, we frame our research question in this paper as: How can we assist pBLV in recognizing scenes, identifying objects, and detecting potential tripping hazards in unfamiliar environments, where existing assistive technologies often falter due to their lack of robustness? We hypothesize that by leveraging large pretrained foundation models and prompt engineering, we can create a system that effectively addresses the challenges faced by pBLV in unfamiliar environments. Motivated by the prevalence of large pretrained foundation models, particularly in assistive robotics applications, due to their accurate perception and robust contextual understanding in real-world scenarios induced by extensive pretraining, we present a pioneering approach that leverages foundation models to enhance visual perception for pBLV, offering detailed and comprehensive descriptions of the surrounding environment and providing warnings about potential risks. Specifically, our method begins by leveraging a large-image tagging model (i.e., Recognize Anything Model (RAM)) to identify all common objects present in the captured images. The recognition results and user query are then integrated into a prompt, tailored specifically for pBLV, using prompt engineering. By combining the prompt and input image, a vision-language foundation model (i.e., InstructBLIP) generates detailed and comprehensive descriptions of the environment and identifies potential risks in the environment by analyzing environmental objects and scenic landmarks, relevant to the prompt. We evaluate our approach through experiments conducted on both indoor and outdoor datasets. Our results demonstrate that our method can recognize objects accurately and provide insightful descriptions and analysis of the environment for pBLV.