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Biomedical subjects

R A Abrams

Publications and source records attributed to R A Abrams.

At least 37 records · Page 2Linked to original sources
PubMed1999

Intensified adjuvant therapy for pancreatic and periampullary adenocarcinoma: survival results and observations regarding patterns of failure, radiotherapy dose and CA19-9 levels.

PURPOSE: Primary endpoints were 1. To determine if, in the context of postoperative adjuvant therapy of pancreatic and nonpancreatic periampullary adenocarcinoma, continuous infusion (C.I.) 5-fluorouracil (5-FU) and leucovorin (Lv), combined with continuous-course external-beam radiotherapy (EBRT) to liver (23.4-27.0 Gy), regional lymph nodes (50.4-54.0 Gy) and tumor bed (50.4-57.6 Gy), followed by 4 months of C.I. 5-FU/Lv without EBRT could be given with acceptable toxicity. 2. To determine an estimate of disease-free and overall survival (DFS, OS) with this treatment in this context. Secondary endpoints were 1. To observe the effects of therapy at two different dose levels of irradiation, and 2. To observe for correlations among DFS, OS and CA 19-9 levels during therapy. METHODS: Patients received C.I. 5-FU 200 mg/m2 and Lv 5 mg/m2 Monday through Friday during EBRT, and 4 cycles of the same chemotherapy without EBRT were planned for each 2 weeks of 4, beginning 1 month following the completion of EBRT. Therapy was to begin within 10 weeks of surgery and patients were monitored for disease recurrence, toxicity, and CA 19-9 levels before the start of EBRT/5-FU/Lv, before each cycle of C.I. 5-FU/Lv, and periodically after the completion of therapy. There were two EBRT dosage groups: Low EBRT, 23.4 Gy to the whole liver, 50.4 Gy to regional nodes and 50.4 Gy to the tumor bed; High EBRT, 27.0 Gy to the whole liver, 54.0 Gy to regional nodes, and 57.6 Gy to the tumor bed. RESULTS: 29 patients were enrolled and treated (23 with pancreatic cancer, and 6 with nonpancreatic periampullary cancer). Of these, 18 had tumor sizes > or = 3 cm and 23 had at least one histologically involved lymph node; 6 had histologically positive resection margins. Mean time to start of EBRT/5-FU/Lv was 53 +/- 2 days following surgery. The first 18 patients were in the Low EBRT Group and the last 11 in the High EBRT Group. Toxicity was moderate and manageable, including a possible case of late radiation hepatitis. Median DFS was 8.3 months (pancreatic cancer patients 8.5 months) and OS was 14.1 months (pancreatic cancer patients 15.9 months). Among patients with pancreatic cancer, results were similar for the Low and High EBRT Groups (DFS: 8.3 vs. 8.6 months; OS: 14.4 vs. 16.9 months, respectively). With a mean follow up of 2.6 +/- 0.3 years for the surviving patients and a minimal follow-up of 2.5 years, 27 of 29 pts have relapsed and 25 pts have died. A rise in CA 19-9 levels preceded clinical relapse by 9.1 +/- 1.5 months. Time to first relapse by site showed inverse correlation with dose of radiotherapy to that site: peritoneal (5 +/- 1 month), hepatic (7 +/- 0.9 months), regional nodes/tumor bed (9.6 +/- 1.8 months). Mean postresection CA 19-9 level was 63.3 +/- 16.2 U/ml. Postresection CA 19-9 values did not correlate with survival, margin status, or with the identification of metastatic carcinoma in resected lymph nodes. However, among patients with histologically involved nodes in the resected specimen, postresection CA 19-9 values did correlate with the number of positive nodes identified (p = 0.05). CONCLUSIONS: Although toxicity was acceptable, survival results were not improved over those seen with standard adjuvant treatment. Most patients relapsed before the planned chemotherapy cycles were completed, or within 100 days thereof, suggesting disease resistance to C.I. 5-FU/Lv as used in this study. Although this regimen is not recommended for further study, the doses of EBRT utilized may be suitable for evaluation with other chemotherapy combinations. Postoperative CA 19-9 levels did not correlate with survival, but did correlate with the number of histologically involved lymph nodes found in the resected specimen among node-positive patients. Moreover, rising CA 19-9 levels anticipated ultimate clinical failure by 9 months.

Adenocarcinoma↗
PubMed1999

HIV-associated primary CNS lymorbidity and utility of brain biopsy.

INTRODUCTION: Human immunodeficiency virus (HIV) infection is associated with several central nervous system (CNS) infections and neoplasms. These opportunistic processes generally occur with advanced immunosuppression, but if an accurate diagnosis is made, effective treatment can frequently be initiated. METHODS: In an attempt to assess the safety, diagnostic yield, and utility of stereotactic brain biopsy in the clinical management of suspected HIV-associated primary CNS lymphoma, we retrospectively studied the performance of biopsy in HIV-seropositive patients presenting with focal intracranial lesions. This analysis included 435 patients undergoing brain biopsy, identified through a local case series (n=47) combined with all published cases (n=388). The years of analysis for this study were 1984 and 1997. We also assessed the survival of HIV-associated intracranial mass lesions and of PCNSL patients treated at JHU. RESULTS: Definitive histopathological diagnoses were established in eighty-eight percent of biopsied cases: primary CNS lymphoma (PCNSL) (30%), CNS toxoplasmosis (CNS TOXO) (16%), progressive multifocal leukoencephalopathy (PML) (25%), and other specific diagnoses (17%). Post-biopsy morbidity within thirty days was 8.4% and mortality was 2.9%. PCNSL was the most common diagnosis among cases biopsied after failure of anti-toxoplasmosis therapy, 134/205 (65%). In the local case series, biopsy-related morbidity was associated with poor functional status, decreased platelet count, and number of lesions at presentation. The median survival of irradiated PCNSL cases was 29 days longer than untreated cases (median survival 50 days versus 21 days, respectively, Chi-square=6.73, P<0.01). DISCUSSION: Stereotactic brain biopsy had a high diagnostic yield for HIV-associated focal intracranial lesions, however, the biopsy complication rate in this patient population was relatively high. PCNSL was diagnosed in the majority of patients failing anti-toxoplasmosis therapy. Survival after irradiation for PCNSL remains very poor.

AIDS Dementia Complex↗
PubMed1999

The Gap effect for spatially oriented responses.

The gap effect refers to the finding that a temporal gap between fixation point offset and target onset typically results in shorter saccadic latencies than if the fixation point remains on. Recently, this gap effect was found for aimed hand movements as well as saccadic eye movements, but not for simple keypress responses. In order to examine the hypothesis that the hand gap effect occurs for different types of spatially oriented movements, two experiments were conducted. In the first experiment, subjects produced spatially oriented responses to a peripheral target and the target location was known in advance of the targets presentation. This spatially oriented detection task yielded gap effects for both eye and hand responses. In the second experiment, the duration of the temporal gap was varied between 0-400 ms. The duration of the temporal gap had similar effects on the magnitudes of both the eye and hand gap effects, suggesting that a common mechanism may underlie the gap effect for saccadic and manual pointing movements. Overall, the results of the present experiments confirm the finding of a gap effect for spatially oriented hand movements and suggest that this effect may be related to the functioning of the superior colliculus.

Fixation, Ocular↗
PubMed1999

Inhibition of return in discrimination tasks.

Although inhibition of return is known to affect a wide range of detection tasks, it has not been found consistently in discrimination tasks. To examine this issue, 5 experiments were conducted in which participants discriminated between a visual target and a distractor. The responses were not inhibited if, before the onset of stimuli, attention had been overtly oriented (i.e., an eye movement was made) to the future target location and the stimulus at that location was the same symbol as the upcoming target. However, if attention was covertly oriented (i.e., no eye movement was made) to the future location of the target, or if the stimulus at the earlier attended location was a symbol different from the target, responses to the target were inhibited. Overall, the findings provide insights into the relation between movements of attention and discrimination judgments and support the notion that inhibition of return is an attentional phenomenon.

Adult↗
PubMed1999

Metastatic nonresectable fibrolamellar hepatoma: prognostic features and natural history.

Fibrolamellar hepatoma has a clinical course distinct from that of typical histologic hepatocellular carcinoma. The clinical behavior and prognostic features of nonresectable metastatic fibrolamellar hepatoma have not previously been fully addressed and are the focus of this report. Retrospective chart review of all patients (n = 17) with nonresectable metastatic fibrolamellar hepatoma referred to the Johns Hopkins Oncology Center from 1985 through 1990 was carried out. All patients had hepatic parenchymal involvement and regional node metastases at the time of referral. Metastases were limited to regional nodes in four patients. The remaining patients had lung metastases (n = 4), peritoneal metastases (n = 5), or both (n = 4). To assess the impact of the fibrolamellar variant, characteristic-matched control patients with typical histologic hepatocellular carcinoma were obtained from the Radiation Therapy Oncology Group database. Actuarial median survival from treatment was 14 months in the patients with fibrolamellar hepatoma and 7.7 months in the patients with hepatocellular carcinoma (p < 0.001). Karnofsky performance status and hepatic tumor volume at time of referral were important prognostic features. Multimodality treatment included radiation therapy and radiolabelled antibody, cisplatin-based chemotherapy, or both; results are discussed. Thirteen patients died, nine of liver failure, three of metastatic disease, and one of sepsis. Fibrolamellar histologic type, liver function tests, tumor volume, and patient performance status were significant predictors of survival. The cause of death in fibrolamellar hepatoma differs considerably from that observed in typical histologic hepatocellular carcinoma in the United States. The techniques of treatment of this uncommon disease were modeled after advances in the multimodality treatment of hepatocellular carcinoma and are discussed. Median survival was 14 months in patients with metastatic nonresectable fibrolamellar hepatoma.

Adult↗
PubMed1998

Adjuvant therapy for pancreatic cancer: back to the future.

PURPOSE: The role of adjuvant therapy in the management of pancreatic cancer, resected with curative intent, remains controversial. This editorial review updates the status of adjuvant therapy in this context and introduces the first North American co-operative group study in this arena in roughly 20 years. RESULTS: To the extent that there has been a "standard" of care in this context, it has been defined in large part by the early work of the Gastrointestinal Study Group (GITSG). Their trial was activated in the mid 1970's using split course radiation therapy and bolus 5-FU. In the intervening 20 + years the morbidity/mortality of pancreaticoduodenectomy (PDD) has been dramatically reduced; concurrently, understanding of prognostic factors impacting on outcomes for resected patients has been significantly enhanced. In major centers the mortality of PDD is roughly 1% and survival has been shown to correlate with a number of factors including tumor size, nodal involvement, and margin status. With currently available techniques doses of continuous course radiation therapy in the range of 50-55 Gy to sites of pancreatic tumor resection and adjacent lymph node regions have been given in a number of trials with acceptable morbidity. 5-FU sequencing and administration have been advanced and gemcitabine, an agent with clear radiosensitizing properties, has been approved for use against pancreatic cancer. CONCLUSIONS: Following PDD increasing numbers of physiologically intact patients are confronting the survival statistics associated with resected pancreatic cancer. Their interest in improved therapeutic outcomes, combined with the noted improvements in radiation and chemotherapeutic management, has set the stage for renewed and intensified study. Accordingly, the intergroup mechanism of the Cancer Therapy and Evaluation Program (CTEP) of the NCI has designed, approved, and activated a modern Phase III, adjuvant protocol incorporating recently gained knowledge in this management context. Prospective randomization will be utilized to compare gemcitabine and 5-FU as single agents before and after chemoradiotherapy with 5-FU. Successful and timely completion of this newly activated intergroup study, RTOG 97-04, will establish a current, cooperative group experience, data base, and standard in the context of adjuvant therapy for pancreatic cancer and serve to provide momentum for further studies.

Antimetabolites, Antineoplastic↗
PubMed1998

Tensile properties of the neurorrhaphy site in the rat sciatic nerve.

Forty-three epineurial rat sciatic neurorrhaphies were performed to gain insight into the duration necessary to protect a nerve repair. By killing animals at varying intervals after neurorrhaphy and harvesting the sciatic nerves, we investigated the timing of neurorrhaphy site tensile property recovery. There were 9 normal control nerves. No nerves ruptured after repair, even though the operated legs were not immobilized. Ultimate and maximal simulated in situ loads and elongations were measured, and stresses and strains were calculated from mechanical testing. Sixty-four percent of normal ultimate stress was gained during the first week after neurorrhaphy, with no significant increase for 10 to 12 weeks. Ultimate strains for control and repaired nerves for all time intervals ranged from 14.2% +/- 1.8% to 26.0% +/- 3.9%. Maximal simulated in situ stress and strain remained in the toe region of the stress versus strain curve, implying that no nerves ruptured because ultimate stress and strain were never approached. Caution must be exercised in extrapolating these data to the human clinical situation.

Animals↗
PubMed1998

The role of ulnar nerve transposition in ulnar nerve repair: a cadaver study.

Ulnar nerve transposition at the elbow is recommended to diminish nerve gaps during neurorrhaphy. We undertook a cadaver study to determine the gap distance that can be overcome by subcutaneous transposition at the elbow, evaluating lacerations 2.0 cm distal to the medial epicondyle and 2.0 cm proximal to the wrist crease. With a 100-g load on each nerve stump, gaps that could be overcome were measured before and after transposition in different elbow and wrist positions. For the distal forearm lacerations, wrist position significantly affected nerve gap, while transposition and elbow position did not. Nerve gap was significantly reduced by approximately 11 mm with wrist flexion from 0 degrees to 45 degrees. For proximal forearm lacerations, gap distance was significantly affected by transposition and was dependent to a greater extent on the interaction between transposition and elbow position, with wrist position having no effect. A clinically relevant scenario for the proximal laceration compared the pretransposition gap with the elbow and wrist at neutral with the posttransposition gap with the elbow and wrist flexed. Posttransposition gap reduction, with elbow and wrist flexion at 45 degrees, was approximately 9 mm and was not significant. To span a gap near the elbow, we estimate that more than 45 degrees of elbow flexion is required.

Aged↗
PubMed1998

Aging and movement: variability of force pulses for saccadic eye movements.

Age-related differences in the trajectories of saccadic eye movements were examined. Younger and older adult subjects produced saccades to predictable target locations. Detailed features of the movements were examined such as the time of peak acceleration and the variability in the magnitude of the peak velocity. These and other measures reveal important details of the force pulses underlying the eye movements and the mental mechanisms that control them. Although minor differences were apparent between the eye movements of younger and older adults, the general patterns were the same across age groups. These results suggest that fundamental details of the brain mechanisms involved in the control of movement are the same for younger and older adults.

Adult↗
PubMed1998

Fixation point offsets facilitate endogenous saccades.

Subjects produced saccades to continuously visible targets that were signaled by the pitch, not the location, of an auditory signal. Such endogenous saccades were initiated more quickly when the visual fixation point disappeared 200 msec before the signal (thus producing a "gap"), even though the alerting benefits of such a warning were eliminated by an earlier warning tone. The presence of the gap effect under these circumstances shows that the effect is more general than was previously believed: Visual fixation point offsets facilitate saccades by affecting oculomotor processes related to both visually elicited (exogenous) and centrally produced (endogenous) saccades. In addition, the magnitude of the gap effect for endogenous saccades was significantly smaller than that for exogenous saccades, suggesting that at least some of the effect arises in relatively early processes, such as those involved in the processing of sensory signals, and not exclusively in later processes, such as those involved in the preparation and production of saccades.

Adult↗
PubMed1998

Exertional compartment syndrome of the upper extremity.

Exertional compartment syndrome is characterized by intracompartmental pressures that rise transiently following repetitive motion or exercise, thereby producing temporary, reversible ischemia, pain, weakness, and, occasionally, neurologic deficits. The exact cause or pathogenesis remains unclear; a disturbance of microvascular flow caused by elevated intramuscular pressure leads to tissue ischemia, depletion of high-energy phosphate stores, and cellular acidosis. Anatomic contributing factors may include a limited compartment size, increased intracompartmental volume, constricted fascia, loss of compartment elasticity, poor venous return, or increased muscle bulk. The diagnosis is suspected based on history and confirmed with physical examination and intramuscular pressure evaluation before and after exercise (stress test). Differential diagnosis includes claudication or other vascular abnormalities, myositis, tendinitis, periostitis, chronic strains or sprains, stress fracture, other compression or systemic neuropathies, and cardiac abnormalities with angina or referred extremity pain. Initial treatment includes activity modification; refractory symptoms can be managed with elective fasciotomy.

Chronic Disease↗
PubMed1997

Influence of prognostic groupings and treatment results in the management of unresectable hepatoma: experience with Cisplatinum-based chemoradiotherapy in 76 patients.

PURPOSE: Internationally, hepatoma is a common cause of cancer death. Although the only curative therapy is surgical, most tumors are unresectable and cause death. The value of nonsurgical, antineoplastic therapy for such tumors is controversial. This study was undertaken to extend and confirm promising, but preliminary, treatment observations in the unresectable context. METHODS AND MATERIALS: From 1988 to 1993, 76 patients with unresectable, biopsy proven, hepatoma underwent uniform pretreatment assessment followed by induction therapy with external beam radiotherapy (21 Gy/7 fractions/10 days) and intravenous Cisplatinum, 50 mg/m2. One month later patients began monthly intrahepatic artery Cisplatinum, 50 mg/m2. Clinical course and treatment outcomes were correlated with previously published prognostic factors and groupings (Nomura et al., Okuda et al., Stillwagon, et al.). RESULTS: The toxicity of this therapy was modest and nonlimiting. Twenty-four patients (32%) progressed during induction and prior to receiving two cycles of intrahepatic artery Cisplatinum without evidence of benefit. Patients showing this early progression were more likely to be Stillwagon unfavorable than favorable (p = 0.013), Okuda Stage II than Stage I (p = 0.024), and slightly but not statistically more likely to be alpha-fetoprotein positive than alpha-fetoprotein negative (p = 0.098). The overall objective response rate was 43% (38% among AFP positive and 62% among AFP negative patients) (p = 0.15). Although 21 patients had evidence of extra hepatic metastases, survival for these patients did not differ from patients without metastases (p = 0.09) and patients with extra hepatic metastases were just as likely to show intrahepatic response (p = 0.84). CONCLUSION: The chemoradiotherapy program utilized produced objective response and minimal toxicity. One-third of patients progressed rapidly in spite of treatment. Among the remaining patients, response occurred frequently. This treatment appears to represent an important therapeutic option for many, but not all, patients with unresectable hepatoma.

Adult↗
PubMed1997

p53 status and prognosis of locally advanced prostatic adenocarcinoma: a study based on RTOG 8610.

BACKGROUND: The p53 tumor suppressor gene (also known as TP53) is one of the most frequently mutated genes in human cancer. Several studies have shown that p53 mutations are infrequent in prostate cancer and are associated with advanced disease. PURPOSE: We assessed the prognostic value of identifying abnormal p53 protein expression in the tumors of patients with locally advanced prostate cancer who were treated with either external-beam radiation therapy alone or total androgen blockade before and during the radiation therapy. METHODS: The study population consisted of a subset of patients entered in Radiation Therapy Oncology Group protocol 8610 ("a phase III trial of Zoladex and flutamide used as cytoreductive agents in locally advanced carcinoma of the prostate treated with definitive radiotherapy"). Immunohistochemical detection of abnormal p53 protein in pretreatment specimens (i.e., needle biopsies or transurethral resections) was achieved by use of the monoclonal anti-p53 antibody DO7; specimens in which 20% or more of the tumor cell nuclei showed positive immunoreactivity were considered to have abnormal p53 protein expression. Associations between p53 protein expression status and the time to local progression, the incidence of distant metastases, progression-free survival, and overall survival were evaluated in univariate (logrank test) and multivariate (Cox proportional hazards model) analyses. Reported P values are two-sided. RESULTS: One hundred twenty-nine (27%) of the 471 patients entered in the trial had sufficient tumor material for analysis. Abnormal p53 protein expression was detected in the tumors of 23 (18%) of these 129 patients. Statistically significant associations were found between the presence of abnormal p53 protein expression and increased incidence of distant metastases (P = .04), decreased progression-free survival (P = .03), and decreased overall survival (P = .02); no association was found between abnormal p53 protein expression and the time to local progression (P = .58). These results were independent of the Gleason score and clinical stage. A significant treatment interaction was detected with respect to the development of distant metastases: Among patients receiving both radiation therapy and hormone therapy, those with tumors exhibiting abnormal p53 protein expression experienced a reduced time to the development of distant metastases (P = .001); for patients treated with radiation therapy alone, the time to distant metastases was unrelated to p53 protein expression status (P = .91). CONCLUSIONS: Determination of p53 protein expression status yield significant, independent prognostic information concerning the development of distant metastases, progression-free survival, and overall survival for patients with locally advanced prostate cancer who are treated primarily with radiation therapy. IMPLICATIONS: The interaction of radiation therapy plus hormone therapy and abnormal p53 protein expression may provide a clinical link to experimental evidence that radiation therapy and/or hormone therapy act, at least in part, by the induction of apoptosis (a cell death program) and suggests that this mechanism may be blocked in patients whose tumors have p53 mutations.

Adenocarcinoma↗
PubMed1997

Functional recovery following neurorrhaphy of the rat sciatic nerve by epineurial repair compared with tubulization.

Recovery of motor function is often poor following transection injuries to peripheral nerves. The purpose of this study was to measure and compare functional recovery of the sciatic nerve in the rat following transection and neurorrhaphy with the use of a nerve guide tube and with traditional end-to-end epineurial repair. Muscle recovery was also evaluated following a crush injury, a model of an axonotmetic lesion. Recovery was assessed at 8, 16, and 32 weeks after injury by measuring the isometric contractile properties of the soleus muscle and at 8 and 16 weeks by measuring the conduction properties of the sciatic nerve. The mean conduction velocity of the sciatic nerve in the crush group and both transection groups was significantly slower than that of controls at both 8 and 16 weeks. Following a transection injury, the soleus became a significantly faster muscle as measured by time to peak twitch tension. By 32 weeks, the maximum isometric tension of the soleus muscle recovered to 90% that of the control group following a crush injury and to less than 70% following a transection injury and repair. Recovery was better in the epineurial repair group than in the tube repair group at 8 weeks, but no difference was found between the groups at 16 or 32 weeks. These results demonstrate that nerve guide tubes are a potential alternative to epineurial repair. The poor motor recovery following repair of transection injuries may be related to poor specificity of reinnervation.

Anastomosis, Surgical↗
PubMed1997

Anatomy of the radial nerve motor branches in the forearm.

Knowledge of radial nerve motor branch anatomy is important when performing surgery in its vicinity, neurorrhaphy, and nerve blocks and for understanding the rate and order of recovery of muscle function after injury. Twenty normal fresh cadaver arms were dissected to quantitate radial nerve motor branch anatomy in the forearm. Though variable in individual specimens, innervation order from proximal to distal (based on mean shortest branch lengths) was brachioradialis, extensor carpi radialis longus, supinator, extensor carpi radialis brevis, extensor digitorum communis, extensor carpi ulnaris, extensor digiti quinti, abductor policis longus, extensor policis longus, extensor policis brevis, and extensor indicis proprius. In 10 specimens, branches innervated the branchialis. Mean distances from a point 100 mm proximal to the lateral epicondyle to the muscle measured along the shortest nerve branch ranged from 97.2 mm for the brachioradialis to 299.8 mm for the EIP. The mean number of muscular branches ranged from 1.1 in the EIP to 4.6 in the EDC. Mean nerve length from the radial styloid to the last motor branch was 115.8 mm.

Cadaver↗
PubMed1997

Age Group Differences in Postural Adjustments Associated With a Stepping Task.

In this study, differences among age groups in the postural adjustments associated with a stepping task were identified. Twenty subjects from each of 3 age groups, children (8-12 years), young adults (25-35 years), and older adults (65-73 years), performed the task in 2 movement contexts: place and step. In place, the subject simply lifted the foot and placed it on the step. In step, the subject lifted the foot, placed it on the step, and stepped up onto the step. Latencies of postural and focal muscle activation were determined by using surface electromyography and pressure switches. Center of pressure (CP) data were obtained by using a force platform. Subjects in all 3 age groups consistently demonstrated postural adjustments before movement initiation. Children displayed longer postural latencies than young adults as well as disproportionately large values for CP path length. Older adults showed prolonged postural-focal latencies and decreased CP excursions compared with the 2 younger age groups. These results suggest that maturation of coordination between posture and movement may not be fully complete in 8- to 12-year-olds and that increased restraint characterizes the performance of postural adjustments in healthy persons over 65 years of age.

center of pressure↗
PubMed1997

Initiation and inhibition of saccadic eye movements in younger and older adults: an analysis of the gap effect.

Previous research with young adults has shown that the latency to initiate a saccadic eye movement is typically reduced when the visual fixation stimulus is removed prior to the appearance of a peripheral target stimulus (the "gap effect"). The present study sought to determine whether such fixation offsets would produce similar reductions in reaction time in both younger and older adults. The results indicated that older adults have longer overall latencies to initiate saccadic eye movements and that they exhibit the gap effect. However, the reduction in reaction time due to the fixation offset was approximately equal between younger and older adults relative to the overall saccadic latencies. These findings, along with some other recent evidence, suggest that some of the mechanisms involved in the production of saccadic eye movements may not reveal the changes often found in the skeletal motor system with increasing age. The implications of the findings to age-related differences in inhibitory function are discussed.

Acoustic Stimulation↗