Search

Purpose: To evaluate the frequency of retinal detachments following prophylactic transpupillary retinopexy (PTPRP)., Methods: The medical records of dogs that received a PTPRP between 2014 and 2022 were retrospectively analyzed for age, sex, breed, reason for retinopexy, laser power setting, number of retinal burns, follow-up duration, and outcome. Laser power settings were increased until retinal burns could be visualized and were made 360° in a double row in the peripheral retina., Results: Fifty-seven cases (75 eyes), 28 males and 29 females, had PTPRP performed. The median age was 8 years (4 months-14 years) with Shih tzu (n = 12), Bichon (n = 5), Miniature Poodle (n = 5), and Yorkie (n = 4) being the most common breeds. PTPRP were performed due to severe vitreal degeneration (n = 66), retinal detachment in the contralateral eye (n = 25), capsular tear with escaped lens material during phacoemulsification (n = 6), intracapsular lens extraction (n = 2), and lens luxation during phacoemulsification (n = 3). The median power setting, number of retinal burns, and follow-up time were 300 mW (201-595 mW), 210 burns (35-921 burns), and 473 days (14-1862 days), respectively. Additionally, five patients had a barrier-pexy performed in the contralateral eye, due to partial detachment. Retinal detachment occurred in 3/75 (4.0%) of eyes that received a PTPRP at the final examination. Of the patients with a detachment in the contralateral eye (n = 25), no detachment was noted at the last follow-up examination. Two partial detachments that had barrier-pexies had progressed at the final examination., Conclusions: These results demonstrate that PTPRP may be beneficial in decreasing the risk of retinal detachment in selected cases., (© 2024 American College of Veterinary Ophthalmologists.)

The life and works of the great American artist Andy Warhol (1928-1987) are examined in the context of Warhol's compulsive and often gratuitous lying. Elements of early trauma-contracting St. Vitus Dance at age of 7, his father's death at age of 13, and the abject poverty in which he grew up as the son of immigrants-are viewed as central antecedents of his deceptiveness. The relevance of these dynamics to the clinical situation is examined., (© 2019 Wiley Periodicals, Inc.)

Numerous studies indicate the importance of the hippocampus to temporal order retrieval. However, behavioral studies suggest that there are different ways to retrieve temporal order information from encoded sequences, one involving an associative strategy (retrieving associations using neighboring items in a list) and another involving a recency strategy (determining which of two items came first). It remains unresolved, however, whether both strategies recruit the hippocampus or only associative strategies, consistent with the hippocampus's role in relational processing. To address this, we developed a paradigm in which we dissociated associative versus recency-based retrieval, involving the same stimulus presentation during retrieval. Associative retrieval involved an increase in RT (and decrease in performance) with greater distances between intervals, consistent with the need to retrieve intervening associations. Recency-based retrieval involved an increase in RT (and decrease in performance) with shorter distances between intervals, suggesting the use of a strength-based coding mechanism to retrieve information. We employed fMRI to determine the neural basis of the different strategies. Both strategies showed significant levels of hippocampal activation and connectivity that did not differ between tasks. In contrast, both univariate and connectivity pattern analyses revealed differences in extrahippocampal areas such as parietal and frontal cortices. A covariate analysis suggested that differences could not be explained by task difficulty alone. Together, these findings suggest that the hippocampus plays a role in both forms of temporal order retrieval, with neocortical networks mediating the different cognitive demands for associative versus recency-based temporal order retrieval.

The rodent hippocampus represents different spatial environments distinctly via changes in the pattern of "place cell" firing. It remains unclear, though, how spatial remapping in rodents relates more generally to human memory. Here participants retrieved four virtual reality environments with repeating or novel landmarks and configurations during high-resolution functional magnetic resonance imaging (fMRI). Both neural decoding performance and neural pattern similarity measures revealed environment-specific hippocampal neural codes. Conversely, an interfering spatial environment did not elicit neural codes specific to that environment, with neural activity patterns instead resembling those of competing environments, an effect linked to lower retrieval performance. We find that orthogonalized neural patterns accompany successful disambiguation of spatial environments while erroneous reinstatement of competing patterns characterized interference errors. These results provide the first evidence for environment-specific neural codes in the human hippocampus, suggesting that pattern separation/completion mechanisms play an important role in how we successfully retrieve memories.

Loss of autonomic balance characterized by increased sympathetic activity and decreased vagal activity has been implicated as a major cardiovascular risk factor. Aspirin's cardioprotective abilities involve a multitude of physiologic processes. However, the effects of aspirin on cardiac autonomic activity are unknown. In a double-blind crossover study, 22 subjects randomly received either aspirin or placebo in the amounts of 325 mg with each meal (three times per day) over a 2.5-day period. The total amount of aspirin ingested was 2,275 mg, which resulted in plasma levels of 3.3 mg/dl. At the conclusion of each treatment, subjects were evaluated for autonomic physiology activity using standard autonomic tests. Power spectral analyses of the electrocardiograms were used to delineate autonomic function. A 2 x 4 repeated measures analysis of variance revealed significant and favorable changes in autonomic activity after the use of aspirin. Specifically, at rest high-frequency (HF) power was significantly higher (mean, 1,090 + 1,463.5 msec2) compared with the placebo (mean, 692 742 msec2) (p <0.05). Low-frequency (LF) power was significantly reduced (mean, 963 745 msec2) after aspirin compared with placebo (mean, 1,100 906 msec2). After the aspirin treatment, a significantly lower LF-to-HF power ratio (mean, 1.7 2 msec2) was noted at rest when compared with the placebo (mean, 2.5 2.7 msec2) (p <0.05). Similar significant trends were seen during the sustained isometric contraction after aspirin therapy for HF power (mean 210 2.15 msec2) compared with placebo (mean, 213 184 msec2) (p <0.05). Accordingly, the LF-to-HF power ratio was lower as well when compared to placebo treatment (mean, 2.3 3.5 msec2) (mean, 5.3 8.4 msec2) (p <0.05). No differences were found in breathing rates for hemodynamic variables between any of the protocols. The significant reduction of LF-to-HF ratio, a marker of sympathovagal balance, for both protocols appeared to be largely due to a withdrawal of LF modulation and concomitant but lesser increase in HF modulation. Favorable alterations in autonomic outflow through prostaglandin inhibition may be one of the mechanisms by which low therapeutic amounts of aspirin provide prophylactic cardioprotection.

Twenty-six healthy subjects with a diagnosis of Präder-Willi syndrome were compared with 26 age-, gender-, and body mass index-matched controls for autonomic modulation and baroreflex sensitivity. Electrocardiograms, beat-to-beat finger blood pressures, and respiration were recorded for several minutes in the following sequence: (1) supine, (2) after transition from supine to standing, (3) sitting, (4) during a Valsalva maneuver, (5) while performing moderate exercise, and (6) during recovery from exercise while seated. All recordings were channeled and stored in a computer; analyses were carried out at a later date. Power spectral analysis (fast-Fourier transform) of heart period variability was used to assess cardiac autonomic modulation. The slope of the regression equation between heart period and blood pressure rise after the Valsalva maneuver was used as an index of baroreflex sensitivity. Analysis of variance failed to reveal significant differences in any of the autonomic and baroreflex sensitivity variables between the two groups. Because breathing patterns entrain autonomic modulation, we verified respiration and found no differences between the two groups. Therefore, findings in the current investigation indicate that cardiac autonomic modulation in patients with Präder-Willi syndrome does not differ from age and body mass index-matched subjects.

Mechanoreceptor contribution to efferent autonomic outflow is incompletely understood. To determine the effects of mechanoreceptor stimulation on autonomic reflexes, we compared autonomic responses in 34 subjects using a cross-over, counter-balanced design, in which hemodynamic, electromyographic, metabolic, and autonomic data were gathered during rest, passive, and active movement protocols. Because metaboreceptors and ventilatory responses influence autonomic outflow we verified and controlled for these influences during all protocols through comparisons of breath-by-breath gas exchange measurements. Verification of active and passive movements was made via electromyographic recordings of the moving legs. Spectral analysis of R-R variability was used to assess autonomic activity, and low to high frequency ratios were considered representative of sympathovagal balance. A repeated measures analysis of variance revealed significant modulating effects of mechanoreceptor stimulation on sympathovagal balance during passive movement upon efferent autonomic outflow (p < 0.01) independent of central command, chemoreceptor, and metaboreceptor stimulation. Furthermore, breathing frequency and volume were identical for both movement protocols. Therefore, findings in this investigation suggest that modulating influences are being exerted by mechanoreceptor stimulation on autonomic outflow to the heart.

The pathogenesis of blood pressure (BP) rise in aging women remains unexplained, and one of the many incriminating factors may include abnormalities in arteriolar resistance vessels. The aim of this study was to determine the effects of unopposed estrogen on arteriolar distensibility, baroreceptor sensitivity (BRS), BP changes, and rate-pressure product (RPP). We tested the hypotheses that estrogen replacement therapy (ERT) enhances arteriolar distensibility and ameliorates BRS, which leads to decreases in BP and RPP. Postmenopausal women participated in a single-blind crossover study; the participants of this study, after baseline measurements, were randomly assigned to receive estrogen (ERT) or a drug-free treatment with a 6-wk washout period between treatments. The single-blind design was instituted because subjects become unblinded due to physiological changes (i.e., fluid shifts, weight gain, and secretory changes) associated with estrogen intake. However, investigators and technicians involved in data collection and analyses remained blind. After each treatment, subjects performed identical autonomic tests, during which electrocardiograms, beat-by-beat BPs, and respiration were recorded. The area under the dicrotic notch of the BP wave was used as an index of arteriolar distensibility. The magnitude of the reflex bradycardia after a precipitous rise in BP was used to determine BRS. Power spectral analysis of heart rate variability was used to assess autonomic activity. BPs were recorded from resistance vessels in the finger using a beat-by-beat photoplethysmographic device. RPP, a noninvasive marker of myocardial oxygen consumption, was calculated. Repeated-measures analyses of variance revealed a significantly enhanced arteriolar distensibility and BRS after ERT (P < 0.05). A trend of a lower sympathovagal balance at rest was observed after ERT, however, this trend did not reach statistical significance (P = 0.061) compared with the other treatments. The above autonomic changes produced significantly lower systolic and diastolic BP changes and RPPs (P < 0.05) at rest and during isometric exercise. We conclude that short-term unopposed ERT favorably enhances arteriolar distensibility, BRS, and hemodynamic parameters in postmenopausal women. These findings have clinical implications in the goals for treating cardiovascular risk factors in aging women.

Length of stay (LOS) differences were not observed between the dually entitled and other Medicare stroke patients when complexity of disease was considered. LOS for dually entitled heart failure patients was 33.2 percent longer than other Medicare heart failures and were equally likely to be in the extreme DRG subclass. Patients with extreme heart failure stayed 15.5 days longer than those with mild heart failure. LOS differences (+4.5 days) were observed between the dually entitled and other Medicare heart failures when complexity of disease was considered. Within these two DRGs, incremental health care needs for dually entitled equalled 10 percent of the hospital's total Medicare days associated with stroke and heart failure.

Glomerular function was evaluated longitudinally over a 24- to 48-month period in 18 patients with diabetic glomerular disease (DGD) manifested by proteinuria. GFR was determined by iothalamate clearance at 4-month intervals. The patients were divided into two groups: Group 1 (N = 9) had subnephrotic proteinuria and an initially normal GFR of 91 +/- 8 mL/min. Group 2 (N = 9) had nephrotic-range proteinuria, and initial GFR was reduced to 53 +/- 5 mL/min. Serial GFR fluctuated over time in Group 1, but no trend towards hypofiltration was evident. In contrast, GFR declined linearly in Group 2 at 1.1 +/- 0.3 mL/min per month. The transglomerular sieving of uncharged dextrans of graded size was analyzed and initially revealed a uniform reduction in glomerular pore density and an enhancement of shuntlike pores. Pore density was initially reduced by 80% and declined further after 24 months in nephrotic Group 2; corresponding pore density in subnephrotic Group 1 was reduced by half but remained constant. Renal biopsy of four members of Group 1 revealed a 22% prevalence of global glomerulosclerosis. Remaining open glomeruli exhibited hypertrophy, excessive extracellular matrix, and deformation of epithelial podocytes. The latter abnormality appeared to be the predominant determinant of lowered ultrafiltration capacity. It was inferred that trials of therapy to attenuate the progression of DGD should be initiated at a functional level similar to that in subnephrotic Group 1. Because GFR is unlikely to decline over a 2- to 4-yr period, it is suggested that such trials be extended for longer periods. Alternatively, morphometric analysis of serial renal biopsies may shorten the time needed to demonstrate effective renoprotection in DGD.

The percentage of subjects with contractures, mean maximal loss of range, and relative contracture indices are reported in 230 patients, with 11 diseases seen in a neuromuscular disease clinic during a five-year period. The highest percentage of contractures occurred in patients with Duchenne muscular dystrophy. The number of contractures was significantly greater (p less than .001) (1) in the lower than in the upper extremities; (2) in diseases considered myopathic than in those considered neuropathic; (3) in diseases that are X-linked than in those that are not; and (4) in rapidly progressive than in slowly progressive diseases.

Motor neuron disease/amyotrophic lateral sclerosis (MND/ALS) often causes bulbar palsy with subsequent aspiration. Laryngeal diversion procedures are not commonly mentioned in the literature. However, they are viable but infrequently used surgical treatment options that have several advantages over a routine tracheostomy. We report a case of a 67-year-old man with MND/ALS and severe aspiration. He underwent a laryngeal diversion procedure with complete relief of signs and symptoms of aspiration. Laryngeal diversion, unlike tracheostomy, completely eliminates the possibility of aspiration as well as the need for suctioning. The primary disadvantage is complete loss of phonation. These procedures appear worthy of trial in patients with MND/ALS, and may ultimately be the preferred treatment in this setting.

Forty stroke subjects referred for dysphagia and studied by videofluoroscopy were compared with 16 individuals with no known pharyngeal swallowing difficulty. Kinematic pharyngeal transit time was defined as the time from the first movement of the bolus posteriorly resulting in a complete swallow to the return of the epiglottis to its original position. The mean transit time was 1.00 second for the comparative group and 6.15 seconds for the stroke group (p less than 0.001). Other component transit times are described and were all significantly prolonged for the stroke group. There was no significant difference in transit times between right-sided and left-sided lesions except for the segmental interval from onset of bolus movement to arrival at the valleculae, which was significant at p = 0.05. Measurement of transit times using the method described in this study requires equipment available in most hospitals. These measurements may be used in the evaluation of dysphagia in various pathologic disorders, in following the progress of patients with dysphagia, and in evaluating the effects of remedial therapies.

We examined in vitro the effect of ethanol at four concentrations (0g%, 0.1g%, 0.2g%, and 0.4g%) on contractile parameters of 40 fast extensor digitorum longus (EDL) and 40 slow soleus muscles from healthy mice at 35C. Preparations were curarized to avoid the possible effect of ethanol on the terminal axons or skeletal neuromuscular junction. Contractile parameters measured included: (1) twitch and tetanic tension; (2) rate of tension development; (3) time to peak tension and half relaxation for twitch; (4) time to first evidence of relaxation in the tetanus; and (5) maximum rate of relaxation. The three lower concentrations of ethanol had no significant effect on muscle contractility; however, the 0.4g% dose reduced EDL twitch tension by 9%. High doses of ethanol (2.5g%) reduced the tetanic tension produced by the EDL and soleus muscles 31% and 26%, respectively. Ethanol at 2.5g% also reduced the twitch tension of the EDL and soleus by 50% and 38%, respectively. The data suggested that the 0.4g% is the highest dose of ethanol that should be used to dilute drugs in a solution that will bathe directly stimulated curarized muscle without confounding effects. In addition, it is highly unlikely that a direct effect of ethanol on muscle contractility in humans is related to an impairment in driving.

Phrenic nerve and diaphragmatic dysfunction has been assumed to be the cause of respiratory failure in hereditary motor and sensory neuropathy, type 1 (HMSN I). In order to determine the relationship between phrenic nerve and pulmonary function in this disease, 25 patients underwent a 4-step evaluation process consisting of: (1) bilateral phrenic nerve conduction study; (2) median, peroneal, and tibial motor conduction studies; (3) measurement of forced vital capacity (FVC) and maximal inspiratory and expiratory pressures (MIP, MEP); and (4) pulmonary-focused history and physical. Phrenic nerve motor latency was abnormally prolonged in 22 of the 23 (96%) subjects when a response was obtained. All had slowed velocity or absent peripheral motor conduction responses. Vital capacity was abnormally reduced in 6 of the 25 (24%) subjects. Eight (32%) had an abnormally reduced MIP, while 19 (76%) had an abnormally reduced MEP. Only 2 (8%) subjects had clinical evidence of pulmonary dysfunction. None of the dependent variables (FVC, MIP, MEP, peripheral nerve conduction, or clinical examination) correlated with phrenic nerve latencies. Although phrenic nerve latencies are markedly prolonged in HMSN I, these values are not useful in predicting respiratory dysfunction.

The purpose of this study was to use direct in vivo contractility measurements to assess muscle function in patients with myotonic muscular dystrophy (MMD). The tetanic and twitch responses and several time parameters of muscle contraction were obtained from nine MMD subjects and nine able-bodied, age-matched controls. After a routine nerve conduction study, in vivo contractility measurements were obtained by stimulating the ulnar nerve at the wrist and recording the isometric flexor function of the intrinsic muscles at the metacarpophalangeal joint of the index finger. A series of single stimuli, paired stimuli, and fused tetanic stimulations were generated during a 20-minute experimental protocol. A stable tetanus was produced at 50Hz for 1.2 seconds. M-wave and contractile data were recorded at 1,000Hz by digitization of the analog signal and storage by the microcomputer. The MMD patients were weaker than controls (p less than .05), as shown by the 39% reduction in tetanic tension and 57% reduction in twitch tension. The MMD patients also had a significant impairment in relaxing their muscles as shown by the 1,100% increase in half-relaxation time after contraction, even though there was no evidence of repetitive firing after cessation of stimulus. These data show that MMD patients exhibit failure of sarcolemmal activation, altered excitation-contraction coupling mechanisms, and failure of the contractile machinery. The myotonia is due in part, to some defect in the contractile machinery; it is not solely due to failure of sarcolemmal activation.

This report describes and assesses a technique to indirectly stimulate and quantify the human in vivo muscle response for clinical use. A method has been developed to isolate, stimulate, and record the flexor function of the first dorsal interosseus and first volar interosseus at the metacarpophalangeal (MCP) joint by stimulation of the ulnar nerve at the wrist. A microprocessor-based data acquisition and analysis system was built to deliver the electric stimulus and convert the muscle action potential (M-wave) and force measurements into digital form for analysis. To evaluate the technique, the twitch, paired twitch, and tetanic contractions were analyzed in 81 normal subjects. The tension developed by the youngest subjects (14 to 19 years old) was significantly less than the tension developed by subjects in the three older groups (20 to 34 years, 35 to 50 years, and 50 to 65 years); the tensions in the older groups were not significantly different from each other. Only minor gender differences were noted. This indicates that it is necessary to use age-group controls when looking for evidence of a muscle contractile abnormality in patients with neuromuscular disorders. posttetanic potentiation of the twitch was observed in all healthy subjects, and there was no evidence of an age or gender influence. The posttetanic increase in twitch tension was not associated with a prolongation of the twitch contraction time.

We evaluated the renal and hormonal responses to volume expansion induced by water immersion in subjects with diabetic nephropathy (n = 12) and in healthy control subjects (n = 9). Immersion induced similar average increments in sodium excretion (+/- 223 vs. 176 mumol/min) and comparable decrements in renovascular resistance (RVR; -15 vs. -16 U). However, whereas the control subjects responded uniformly, the response among diabetic subjects was highly variable, with a subset of patients exhibiting paradoxical antinatriuresis and vasoconstriction. Immersion was associated with marked elevation of atrial natriuretic peptide (ANP) in plasma of diabetic versus control subjects (61 +/- 9 vs. 19 +/- 2 pM, respectively; P less than 0.001). Yet for each picomolar increment in plasma ANP during immersion, the corresponding increases in urinary excretion of cyclic guanosine monophosphate (26 vs. 279 pmol/min) and sodium (9 vs. 47 mumol/min) and the reciprocal lowering of RVR (0.7 vs. 1.9 U) were blunted in the diabetic versus control group. Volume contraction in the postimmersion period was associated with disproportionate antinatriuresis and renal vasoconstriction in the diabetic group, despite a persistent elevation of ANP (29 +/- 2 vs. 16 +/- 2 pM, P less than 0.01). We propose that renal insensitivity to ANP in diabetic nephropathy could contribute to altered vasoreactivity and abnormal excretory responsiveness to changing plasma volume. Blunted natriuresis in response to ANP release and enhanced sodium retention during volume contraction could account for the expanded extracellular fluid volume that has consistently been reported to accompany the development of diabetic nephropathy.

This study evaluated the age-related and ambulation-related incidence of scoliosis among boys with Duchenne muscular dystrophy (DMD) and the relationship between wheelchair dependency and scoliosis. Charts of 88 DMD boys were reviewed retrospectively. The relationships between age and both wheelchair dependency and scoliosis were graphed as cumulative distributions with increasing patient age. The relationship between ambulation status and scoliosis was analyzed with a stepwise series of chi square analyses, assuming increasing time intervals between wheelchair dependency and scoliosis. Wheelchair dependency and scoliosis were both age-related phenomena. The relationship between ambulation status and scoliosis became significant only after 3.5 years of wheelchair dependency. It should be noted that 24% of boys with scoliosis developed their curves before cessation of ambulation. While development of scoliosis among DMD boys is clearly an age-related phenomenon, its previously assumed relationship to ambulation requires reevaluation.

The corresponding deterioration of upper extremity strength and functional capability with increasing age and the relationship between average strength and function were evaluated in 28 boys with Duchenne muscular dystrophy (DMD). Manual muscle testing (MMT) was used to evaluate strength and the Brooke upper extremity grading scale to rate upper extremity function. Mean MMT was found to relate to age in logarithmic fastion, ie, a 1% increase in age led to a 0.9% decrease in mean MMT. Functional grade (FG) related to age in a more complex fashion, revealing three groups based on age: under age 10, all in FG 1; between ages 10 and 13, concentration in FG 2 through 4; and over age 13, eight of ten in FG 5. Regression analysis did not contribute further useful information. Finally, mean MMT was found to be highly significantly related to FG. The plot of mean MMT against FG revealed an S-shaped curve, with rapidly rising functional grade once an average upper extremity strength of 4w was reached. The Brooke scale appears to be useful in describing upper extremity function among DMD patients, although it may reflect a three-grade rather than a six-grade discrimination capability. In describing the natural history of DMD, this scale demonstrates a pattern of rapid functional deterioration during the early adolescent years. This functional deterioration apparently takes place when the decline in strength reaches a threshold which cannot be compensated by muscle substitutions. At that time function deteriorates along a relatively rapid but undefined course.

Exercise-induced weakness (fatiguing) is described in three patients with cervical compressive radiculopathy. In all three cases, the patients had symptoms only while at work, and in two cases, symptoms occurred in life-threatening situations. All patients had seen several physicians with a functional diagnosis being considered in all cases because of symptoms only at work and the absence of objective findings during examination. Precise history and examination techniques led to the correct diagnosis and treatment after appropriate investigation. The fatiguing weakness in our cases is thought to be a manifestation of early or mild neurologic involvement unmasked by exercise, rather than a manifestation of compression or ischemia.

In vitro studies were performed on fast and slow muscles from mice to determine if secobarbital sodium (SCB) has a direct effect on muscle contractility. All preparations were curarized and stimulation was direct. After baseline studies, SCB was added to the muscle bath in 1 of 4 concentrations-10, 20, 100 and 200 microgram/ml. Tetanic tension was reduced for both muscle types at SCB concentrations greater than or equal to 20 microgram/ml, and loss was progressive with increasing dose. In contrast, twitch tension (P) was increased by SCB at the 2 higher concentrations. The increase in P was due to an increase in rate of tension development plus prolongation of the time parameter (duration) of the twitch. Fatigue was accelerated by SCB for both muscle types. The results indicate that SCB has a direct and similar effect on fast and slow skeletal muscles. The probable sites of action of the drug are the excitation contraction coupling mechanisms and the mechanisms for energy production and/or utilization.

To evaluate fusimotor activity, the response of muscle spindle primary endings to static stretch was recorded from group Ia fibers in 8 control cats and in 31 cats at 3, 6, 14, 30, and 60 days after lumbar spinal cord transection. The spindle responses and clinical status of each group were compared with those of the control group. At 3 days after transection, the cats were hypotonic and mildly hyperreflexic. Spindle responses were significantly depressed. By day 6, the cats were mildly hypertonic and significant spindle recovery had occurred, although the responses were still significantly depressed from control levels. Spindle responses, hypertonia, and hyperreflexia continued to increase to day 30. At this time, spindle responses remained significantly depressed, although the cats were markedly hypertonic and hyperreflexic. A significant change in spindle activity or clinical status did not occur from 30 to 60 days after transection.

Five patients with hypoventilation and paresis of the diaphragm following trauma to the cervical spinal cord, brain stem, or both, were evaluated with phrenic nerve conduction studies while being considered for implantation of a phrenic nerve stimulator. Several distinct patterns of phrenic nerve function were elicited in the various cases, allowing accurate predictions and management decisions to be made. Phrenic nerve conduction studies are felt to be a valuable diagnostic tool in the management of the hypoventilating patient with cranio-cervical trauma. The procedure is safe, rapid, and easily performed at the bedside.

Locked-in Syndrome (LIS) is a rare clinical entity consisting of quadriplegia, paralysis of lower cranial nerves, mutism, and bilateral paresis of horizontal gaze. The prognosis is usually poor. Most patients who do survive have severe residual impairment or develop chronic LIS. Review of the literature shows that recovery has been reported but not systematically studied, particularly with respect to early prognostic signs. We report a case of LIS with bilateral pontine infarctions shown by MRI. Severe neurological deficits included quadriplegia, paresis of horizontal gaze, facial paralysis, and bulbar palsy. Horizontal eye movements were present and smooth by the second week after onset. The patient had almost full functional motor recovery within four months, after a comprehensive rehabilitation program. Fourteen other reported cases of LIS with full recovery had documented recovery of lateral gaze in the early stage. In addition, smooth horizontal gaze is the most frequent activity in incomplete LIS. Early recovery of horizontal eye movement may indicate that the brain lesion is limited and may be a good prognostic sign in LIS.

The purpose of this study was to evaluate a technique for in vitro study of mouse skeletal muscle, to determine if paired stimuli would allow estimation of new time parameters of contraction. Conventional tension measurements were obtained, plus the time measurements from the paired stimulus studies. The muscles were also subjected to fatigue by repetitive tetanization. A fast muscle (extensor digitorum longus or plantaris) and a slow muscle (soleus) were studied in each preparation. Studies were conducted at physiologic (35C) and at nonphysiologic (20C) temperatures. Data obtained indicate that this isometric in vitro method allows subdivision of results into 3 categories of effect due to treatment related to the functional muscle compartments: 1) chronotropic-excitation contraction coupling mechanisms, 2) inotropic- contractile elements, and 3) metabolic (fatigue)-energy supply mechanisms. When results as 20C were compared with physiologic temperature, a negative chronotropic effect was observed for all parameters in all 3 muscles. A positive inotropic effect was observed for twitch with no change or a negative effect for all other tension parameters. The lower temperature produced slight protection from fatigue. Models were developed to demonstrate how data from isometric studies fit the original concepts developed using isotonic methods. The model and method should prove of value in detecting the acute effect of drugs or of other therapy imposed on skeletal muscles.

Extensive investigation of the role of the fusimotor system in the production of hypotonic and hypertonic disorders of posture and tone has been undertaken in humans and experimental animals. The data from human studies have usually been from indirect assessment of the fusimotor system, and results are often contradictory. Results are now available from animal studies utilizing direct recording of muscle spindle afferent discharge in a number of models of human disorder. Conditions resulting in hypotonia, e.g. cerebellar ablations, medullary pyramidotomy, VL nucleus, thalamotomy, acute spinal cord transection, and acute motor cortex ablation uniformly result in a depression of muscle spindle primary afferent discharge. Conditions resulting in hypertonia, e.g. chronic spinal cord transection and chronic motor cortex ablation, fail to show heightened muscle spindle afferent discharge, however. Rather the spindle afferent discharge returns to control levels in the models. Recovery from the hypotonic to the hypertonic state is, however, associated with significant recovery of spindle afferent function.

The effects of serotonin on the contractile properties of the soleus and extensor digitorum longus muscles in mice were studied after chronic intraperitoneal administration with and without a recovery period, and compared to contractile studies of the same muscles performed after acute administration of serotonin. A curarized in vitro preparation of both muscles was used throughout for the contractile studies. In addition, structural changes were studied in the chronic preparations. Chronic serotonin administration produced histologic changes in type 1 and 2A fibers and a reduction in twitch and tetanic tension and the rate of twitch and tetanic tension development limited to the slow (aerobic) soleus muscle. Acute in vitro administration of serotonin altered the contractile properties of both soleus and extensor digitorum longus muscles with the latter being more involved. The effects of chronic serotonin administration appear to be primarily related to ischemia while the effects of acute administration appear to be mediated by direct, nonvascular action on skeletal muscle.

Functional rating scales have been developed for evaluation of upper extremity (UE) and lower extremity (LE) function in Duchenne muscular dystrophy (DMD). The Vignos scale is accepted for LE function and the Brooke scale for UE evaluation. The assumption that UE functional loss parallels LE loss has never been tested. Furthermore, there are no studies examining the relationship between UE/LE strength. This study tests the hypothesis that UE/LE strength and functional losses are parallel in DMD and other neuromuscular disorders. Vignos grades, Brooke grades, and manual muscle test scores were determined for 27 patients with DMD, 10 patients with fascioscapulohumeral muscular dystrophy (FSH), 24 patients with myotonic muscular dystrophy (MMD) and 29 patients with other (Becker's dystrophy and limb-girdle syndrome) proximal myopathies (PM). Spearman correlation coefficients were calculated for UE vs LE functional grade and strength scores and subjected to significance analysis. While all correlations were statistically significantly different from zero (p less than 0.01), all were also significantly different from one (p less than 0.01), none representing perfect equivalence. Coefficients of determination indicated that a maximum of 86% (FSH) of variation in UE rank could be explained purely by observing LE rank. While there is a significant relationship between UE/LE strength and functional grade, these measurements were not found to be entirely equivalent. Therefore, while measures of lower body function or strength might be used as a substitute for UE measurements in drug trials in which global effects are expected, the two measurements are not equivalent when evaluating an individual's clinical status.

Depression was studied in adults with myotonic muscular dystrophy (MMD). The subject groups consisted of 27 MMD patients, an able-bodied control group of 27 adults (CON), a nonprogressively disabled control group of 17 adult paraplegics (SCI), and a progressively disabled neuromuscular disease control group of 11 adults with limb-girdle syndrome (LGS). The study utilized a test battery consisting of the Minnesota Multiphasic Personality Inventory (MMPI), the Institute of Personality and Ability (IPAT) Depression test, the Suicide Probability Scale (SPS), and the California Psychological Inventory (CPI). The MMD group scored significantly higher on the MMPI Depression scale, the IPAT Depression Test, and the SPS Hopelessness subscale, than the CON or SCI groups. Conversely, the MMD group showed lower levels of positive mental health than these two groups on the MMPI Ego Strength and CPI Well-Being scale scores. The MMD group did not differ significantly from the LGS group in any of the five measures. A definite tendency toward depression was evident among MMD patients. A similar tendency was noted in the small LGS group. The progressive and disabling nature of the disease appears to be the major reason for depression in MMD patients. Our data do not support the concept that depression is an intrinsic characteristic of MMD.

Intellectual and cognitive function was studied in 43 patients (21 men and 22 women) with myotonic muscular dystrophy (MMD). The inheritance distribution was 18 paternal, 10 maternal, and 15 unknown. All patients received the Wechsler Adult Intelligence Scale-Revised, the Wechsler Memory Scale, the Halstead-Reitan Neuropsychological Test Battery, and the Aphasia Screening Test. Significantly lower scores (p less than 0.05) were found on all intellectual and cognitive impairment tests in both men and women of the maternal inheritance MMD subgroup, compared with the paternal inheritance MMD subgroup and with the normative data. Scores for patients with paternally inherited disease did not differ significantly from normative data for verbal, performance, or full scale intelligence quotients and memory quotients. There were no significant differences in intellectual and cognitive test scores between men and women for the group as a whole, for the maternal inheritance subgroup, or for the paternal inheritance subgroup. It is suggested that inheritance pattern is a necessary variable in studies investigating intellectual and cognitive function in MMD. Although the reason for the association of lower intellectual and cognitive function in MMD of maternal inheritance is not known, the data presented here may be useful for genetic counseling.