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Biomedical subjects

M Wall

Publications and source records attributed to M Wall.

At least 91 records · Page 5Linked to original sources
PubMed1991

Evaluation of sensitivity and specificity of spatial resolution and Humphrey automated perimetry in pseudotumor cerebri patients and normal subjects.

To determine the sensitivity and specificity of high-pass resolution perimetry ("ring test"), 18 patients with pseudotumor cerebri (PTC) and 18 age-matched controls were examined with the Humphrey program 24-2 and the ring test. Goldmann perimetry also was done to determine if defects found with the ring test were present with another method. Testing with Humphrey perimetry revealed defects in 15 PTC patients and four control subjects; with the ring test, 13 PTC patients and two control subjects had abnormalities. The disturbed areas in the control subjects with both automated tests were not reproducible. Humphrey perimetry had a sensitivity of 83% and the ring test, 72%. The specificities were Humphrey perimetry, 78% and the ring test, 89%. These differences were not statistically significant. Qualitative assessment of the presence and extent of damage using the pointwise probability plots and graphically displayed raw data showed good correlation of the tests in 11 of the 18 patients. The lack of correlation in four of the patients was caused by the presence of a generalized depression or a peripheral contraction on the Humphrey test; this defect, not present on retesting, may have been related to fatigue or poor motivation. The ring test is a sensitive and specific perimetric technique in patients with PTC.

Adult↗
PubMed1991

High-pass resolution perimetry in optic neuritis.

The topography of visual field defects resulting from optic neuritis as measured by spatial resolution perimetry is not known. Using high-pass resolution perimetry, the number and severity of visual field defects in the central visual field was determined in 18 patients with resolved optic neuritis and 18 age-matched controls. Comparisons were made between three groups of eyes: (1) the involved eyes of the patients, (2) the uninvolved eyes of the patients, and (3) the eyes of the controls. Concentric zone analysis showed the involved eyes to have depression of the visual field in all zones with slightly more loss centrally. The "uninvolved" eyes showed a mild equal depression in all zones. Spatial resolution acuity measurements (which correlate directly with the spatial separation of retinal ganglion cell receptive field centers) indicated that the percentage of functioning retinocortical channels for normal eyes, uninvolved eyes, and involved eyes were 112%, 94%, and 58% of the reference normal values, respectively. These differences were all statistically significant. Resolution perimetry of the central visual field of eyes with resolved optic neuritis involves the cecocentral and Bjerrum areas. The loss was often patchy and a combination of cecocentral and arcuate defects. There was also a mild generalized depression of the uninvolved eye.

Humans↗
PubMed1991

Variability of high-pass resolution perimetry in normals and patients with idiopathic intracranial hypertension.

High-pass resolution perimetry, or the "ring test," is a recently developed type of acuity perimetry. To determine its test-retest variability, we studied 10 normals and 10 patients with idiopathic intracranial hypertension (IIH) by testing both eyes four separate times. There was no increase in variability from the center out to 21 degrees of visual field eccentricity. However, there was a significant increase from 22 degrees to 29 degrees in both normals and IIH patients. Unlike light sensitivity threshold automated perimetry, with an increase in threshold level there was no significant increase in variability in either normals or patients. This may be because of the test's method, which thresholds by target size rather than intensity. As expected, there was a large intersubject variability in the patients, with the visual fields being significantly disturbed by analysis of total field, quadrants, concentric rings, and anatomic nerve fiber bundle regions. Surprisingly, there was no significant difference in the total within subject variability of normals and patients. Because with the ring test there is no increase in variability with an increase in threshold, this method of perimetry may have great utility for following patients with disturbed visual fields. The ring test appears to have advantages that promote low test-retest variability.

Adult↗
PubMed1991

Idiopathic intracranial hypertension. A prospective study of 50 patients.

Management of patients with idiopathic intracranial hypertension (IIH) should be based on the presence and progression of visual loss. To characterize the clinical course of IIH more completely, we monitored the clinical status, especially visual function, in 50 consecutive newly-diagnosed patients over a period of 2 to 39 months (average follow-up 12.4 months). The mean age at onset of symptoms was 31 (range 11-58) yrs; 46 (92%) were women and 47 (94%) were obese (mean weight 90 kg). Common symptoms were headache (92%), transient visual obscurations (72%) and intracranial noises (60%); 13 of the patients (26%) initially had complaints of sustained visual loss. There was visual loss as determined by Goldmann perimetry in 96% and by automated perimetry in 92%. Contrast sensitivity testing was abnormal in 50% and Snellen acuity in 22%. Two patients (4%) became blind in both eyes. The Goldmann visual field grade improved in 60% of patients but visual function deteriorated in 5 (10%). Deterioration of visual field grade was significantly associated only with weight gain during the year before diagnosis. Visual loss in patients with IIH is common and is often reversible. Patients should be evaluated by perimetry using an appropriate strategy and contrast sensitivity testing, along with careful examination of the optic discs.

Adolescent↗
PubMed1991

Idiopathic intracranial hypertension.

Although the cause of IIH remains obscure, loss of visual function is common, and patients may progress to blindness. Diagnosis should adhere to the modified Dandy criteria. Recent case-control studies cast doubt on the validity of many frequently cited conditions associated with IIH. Valid associations include obesity, recent weight gain, female sex, vitamin A intoxication, and steroid withdrawal. Management should include serial perimetry using a sensitive disease-specific strategy so the proper therapy can be selected and visual loss prevented or reversed.

Blindness↗
PubMed1990

[Cerebrospinal fluid cytology--a valuable diagnostic method in various neurologic problems].

Cytological examination of cerebrospinal fluid can provide vital diagnostic information, particularly in inflammatory and neoplastic disorders of the nervous system. Not only can the cause of a pleocytosis be established but cytological abnormalities can also be detected in cases where the cell count is normal. Monoclonal antibodies can be used for the characterisation of leukaemic cells.

Antibodies, Monoclonal↗
PubMed1990

A comparison of three clinical methods of spatial contrast-sensitivity testing in normal subjects.

Three methods clinically used for measuring spatial contrast sensitivity were performed monocularly in normal subjects to compare their sensitivity and applicability. The methods tested were (1) the Von Békésy tracking procedure, (2) the Method of Increasing Contrast, both carried out on a Nicolet CS-2000 automated Vision Tester, and (3) the Vistech Contrast Test System, a photographic test chart. The results show that the threshold sensitivities of the Von Békésy tracking procedure and the Method of Increasing Contrast were not significantly different. For sensitivity to middle and high spatial frequency, the Vistech test chart was found to approximate the Method of Increasing Contrast. With automated testing, a slower rate of contrast progression and a larger visual angle produced lower thresholds of detection of the contrast-sensitivity function. Using a slow rate of contrast progression, both the Vistech test chart and the Method of Increasing Contrast were rapidly conducted, easy to administer, and gave good approximations of the spatial contrast-sensitivity function.

Adult↗
PubMed1990

Long-term follow-up of a cohort of children with alpha-1-antitrypsin deficiency.

We assessed lung function, liver function, and smoking attitudes and behavior in 22 adolescents with homozygous alpha 1-antitrypsin deficiency whose condition had been detected through neonatal screening in the early 1970s. All subjects had normal lung volumes, expiratory flow rates, and diffusing capacity except for two siblings with mild asthma whose values reverted to the normal range after administration of an inhaled bronchodilator. Liver function was normal in all subjects with the exception of one boy who had an isolated elevation of alkaline phosphatase activity. Smoking attitudes, as determined by questionnaire, did not differ from those of 130 control subjects, but smoking initiation rates were significantly lower (p = 0.02). We believe that the issue of neonatal screening for alpha 1-antitrypsin deficiency should be reexamined because augmentation therapy for adults with emphysema is now available, and screening followed by family-based smoking intervention may lead to a nonsmoking life-style. The latter is especially important because the current weight of epidemiologic evidence strongly suggests that in nonsmokers with this condition, severe emphysema may never develop or, if it does, it will do so at a much later age than in smokers.

Adolescent↗
PubMed1990

The headache profile of idiopathic intracranial hypertension.

The headache profile of idiopathic intracranial hypertension (IIH, pseudotumour cerebri) has not previously been prospectively studied. We administered a questionnaire to 63 cases at the time of diagnosis. Fifty-eight of the cases had headache and 93% of those with headache reported it to be their most severe ever. Patients characteristically noted a pulsatile headache of gradually increasing intensity that had awakened them. Daily headache occurred in 74% of those reporting headache. Pain in a nerve root distribution or retro-ocular pain with eye movement, uncommon with other headache disorders, help to differentiate this headache syndrome.

Adolescent↗
PubMed1990

Sensory visual testing in idiopathic intracranial hypertension: measures sensitive to change.

Management decisions in idiopathic intracranial hypertension (IIH; pseudotumor cerebri) are based on the presence and change of visual loss. To study this change, we evaluated tests of sensory visual function over time. We used the results of the right eye of 19 patients whose clinical status improved (decrease in papilledema grade), and compared the outcome measures of the initial and final examinations. Contrast sensitivity testing showed significant improvement in the middle and high spatial frequency targets. Snellen acuity and color tests did not change significantly over the same period. Both Goldmann and automated visual field grade significantly improved from the initial to the final visit, while the presence of a defect on confrontation visual fields did not. Numerical analyses of automated perimetry thresholds also showed significant improvement. Generalized loss, most pronounced on the nasal side of the visual field, was present on the initial examination. Generalized improvement followed, least in the central and inferior paracentral areas. Patients with IIH should be followed with contrast sensitivity testing and perimetry using a disease-specific strategy.

Color Perception↗
PubMed1990

Loss of P retinal ganglion cell function in resolved optic neuritis.

To determine the relative loss of P and M (X and Y) ganglion cell function in unilateral resolved optic neuritis, 10 patients with 20/20 or better Snellen acuity in both eyes had contrast sensitivity testing, color vision testing, and automated perimetry. We used contrast sensitivity gratings of 0.5 cycles per degree (cpd) with a rate of counterphase temporal modulation of 30 Hz and gratings of 11.4 cpd at 1 Hz. On 1 trial, patients responded when they detected the pattern of the grating and on the next trial when they 1st perceived movement. There was a significant difference in the 1 Hz high spatial frequency pattern and movement results suggesting loss of P cell function. Two patients were unable to perceive any movement with their involved eye with this target, but could detect the pattern. There was no significant difference between the involved and uninvolved eyes in the low spatial frequency pattern detection values. This is a function ascribed to the M cell. There was also loss of low spatial frequency movement detection. Although there was significant depression of the entire visual field in the involved eye, the probability plots showed the most significant loss in the cecocentral area. Farnsworth-Munsell 100 Hue color testing was also abnormal. Greater involvement of P than M ganglion cell axons may explain these contrast sensitivity abnormalities, central scotomata, and color vision loss.

Evoked Potentials, Visual↗
PubMed1990

Low-intensity grids improve sensitivity of amsler grid testing in diabetic patients without background retinopathy.

We tested 22 eyes of 12 diabetic patients without retinopathy for visual loss using four types of Amsler grids. The Amsler grids, in order of decreasing intensity, were the standard white, bright red, fine red, and threshold (through cross-polarizing filters). The threshold grid detected the largest number of scotomas--16 versus 12, seven, and seven, respectively--and the largest total area of all scotomas--1594 degrees 2 of arc versus 1237, 994, and 927, respectively. In addition, metamorphopsia lessened as grid intensity decreased. These results demonstrate that the sensitivity of Amsler grid testing for visual loss in diabetics without retinopathy improves by decreasing the intensity of the grid used.

Adult↗
PubMed1988

The incidence of pseudotumor cerebri. Population studies in Iowa and Louisiana.

We surveyed all neurologists, ophthalmologists, and neurosurgeons in Iowa, eastern Nebraska, and Louisiana over one year to determine the annual incidence of pseudotumor cerebri in residents of Iowa and Louisiana. The results were similar for both states. In Iowa, the annual incidence in the general population was 0.9 per 100,000 persons. When obesity was considered, this increased the incidence to 13/100,000 persons in Iowa and 14.85/100,000 persons in Louisiana for women 20 to 44 years of age who were 10% or more over ideal weight. Furthermore, the incidence became 19.3/100,000 for women in the same age range when they were 20% or more over ideal weight. The female-to-male ratio was 8:1, and the mean weight was 38% above ideal weight for height. Pseudotumor cerebri is a relatively common neurologic illness and may be an important preventable cause of blindness in obese young women.

Adult↗
PubMed1988

The clinical and computed tomographic features of cerebellar peduncular hemorrhage.

Three patients with medial ventral cerebellar peduncular hemorrhages presented with a characteristic syndrome. This included (1) ipsilateral ataxia, (2) lower motor neuron type facial weakness, and (3) ipsilateral gaze paresis. The gaze paresis could not be overcome with a doll's head maneuver. The findings are explained by compression of the facial colliculus, with involvement of the sixth nerve nucleus and the middle cerebellar peduncle. Two patients were hypertensive; one was normotensive, and no etiology was identified with angiography. Of 40 patients with cerebellar hemorrhage seen at our institution, only those with medial cerebellar peduncular hematomas demonstrated this clinical triad, and we have not seen this clinical triad in other pathologic conditions. The diagnosis of a small medial cerebellar peduncular hemorrhage was established by CT. In two patients, repeat CT showed complete hematoma resolution. The patients shared a favorable prognosis.

Adult↗
PubMed1988

Gram stain and culture of morning and 24 h sputum in the diagnosis of bacterial exacerbation of chronic bronchitis: a dogma disputed.

Bacteriological results from microscopic and cultural examinations of morning and 24 h sputum were compared in an attempt to optimize the diagnosis of bacterial exacerbations of chronic bronchitis. Twelve patients collected sputum randomly on two consecutive days, either fresh morning sputum (3 h sputum) first, followed by 24 h sputum or vice-versa. Sputa were washed three times in 0.9% NaCl and then examined microscopically before and after homogenization with 2% pancreatin. Cultural examinations were performed on homogenized sputum. Haemophilus influenzae, pneumococci and neisseriae were identified more often in Gram stains than in cultures; staphylococci and Gram-negative rods less frequently so. About 50% of organisms microscopically identified as pneumococci failed to grow in cultures. Microscopic examinations revealed a marked reduction of cells and bacteria after homogenization with pancreatin. Gram stains of 24 h sputum show comparable results to those of morning sputum. No differences were found in cultures. Microscopic examination of the Gram stains was found to be superior to cultural examination. The value of microscopic examination was impaired by the addition of pancreatin.

Bacterial Infections↗
PubMed1987

The management of epilepsy: patients' perceptions and expectations.

An anonymous questionnaire, which was designed to obtain information on satisfaction with medical management, personal attitudes and experiences, and patients' knowledge about epilepsy, was sent to a systematic sample of persons on the membership lists of various Epilepsy Associations across Australia. Comments regarding doctors' attitudes towards persons with epilepsy and the inadequacy of informational exchanges between doctors and patients reflected many respondents' dissatisfaction with their medical management. The problems that are perceived by patients in regard to the management of their epilepsy may be addressed through improved education of these patients and of the community in general. Continuing education of medical practitioners, especially in relation to current management trends, patient education skills and the importance of a positive attitude towards epilepsy, may help to improve patients' perceptions of their medical treatment.

Adolescent↗