| 1. |
- Lindén, Thomas, 1962, et al.
(författare)
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Risk of central pontine myelinolysis in the treatment of severe hyponatremia
- 1989
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Ingår i: Läkartidningen. - 0023-7205. ; 86:20, s. 1905-7
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Tidskriftsartikel (refereegranskat)abstract
- Central pontine myelinolysis is a life-threatening condition involving the demyelination of axons in certain areas of the brain. It has been shown almost invariably to occur in connection with hospital care. In recent years, a connection has been noted between the rapid restitution of low serum sodium and the development of the condition. In this review, the most recent scientific information is summarized. It is concluded that the risk should always be considered in treating a hyponatremic patient. The serum sodium level should be raised slowly and the acute treatment ended before normal serum sodium levels are reached, ie when the patient is still slightly hyponatremic.
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| 2. |
- Hanner, P, et al.
(författare)
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Clinical observations of effects on central nervous system in patients with acute facial palsy.
- 1987
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Ingår i: Archives of otolaryngology--head & neck surgery. - 0886-4470. ; 113:5, s. 516-20
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Tidskriftsartikel (refereegranskat)abstract
- Twenty-eight consecutive patients with acute unilateral facial palsy were examined with special reference to clinical signs of central nervous system involvement. The clinical investigation in the acute stage of the disease showed that only seven patients had solitary facial nerve dysfunction, while the remaining patients had evidence of more widespread disease involvement. The most frequent finding was a trigeminal dysfunction of the paretic side, as shown by paresthesia and sensibility disturbance corresponding to the sensoritrigeminal area, as well as a dysfunction of the trigeminal component of the corneal reflex of the paretic side. Three patients showed migrating symptoms that were suggestive of a brain-stem disorder. In addition, four patients had an optic neuropathy, while an abnormal brain-stem audiometry response was demonstrated in five patients. The outcome of acute facial palsy one to two years after onset, however, could not be predicted from the clinical central nervous system signs. The degree of the palsy in the acute stage of the disease still seemed to be one of the most important prognostic factors. It is concluded that acute facial palsy is not a single entity, but rather a feature of different neurologic conditions.
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| 3. |
- Dahlin, L B, et al.
(författare)
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Mechanical effects of compression of peripheral nerves
- 1986
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Ingår i: Journal of Biomechanical Engineering. - 0148-0731. ; 108:2, s. 2-120
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Tidskriftsartikel (refereegranskat)abstract
- Effects of graded compression on nerve function were analyzed in order to evaluate the relative importance of pressure level and duration of compression for functional deterioration. The pressure was applied by means of a small inflatable cuff. The effects of two pressure levels, i.e., 80 mm Hg applied for 2 hr or 400 mm Hg applied for 15 min, were studied in rabbit tibial nerves. The lower pressure tested, which is known to induce ischemia of the compressed nerve segment, also causes some degree of mechanical deformation of the nerve trunk, which leads to incomplete recovery following pressure release. The duration of compression is of importance for the degree of nerve injury even at the higher pressure level tested.
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| 4. |
- Frisén, Lars, 1939
(författare)
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Acuity perimetry: estimation of neural channels.
- 1988
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Ingår i: International ophthalmology. - 0165-5701. ; 12:3, s. 169-74
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of peripheral visual acuity allow quantitative estimations of retino-cortical neural channels. Analysis of results from high-pass resolution perimetry revealed that about 2/3 of all channels are contained within 30 degrees of visual field eccentricity and that loss of 1/3 raises the average threshold level about 1 decibel. The analytical procedure can be applied to any type of visual field defect.
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| 5. |
- Frisén, Lars, 1939, et al.
(författare)
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Binocular summation in humans: evidence for a hierarchic model.
- 1988
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Ingår i: The Journal of physiology. - 0022-3751. ; 402, s. 773-82
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Tidskriftsartikel (refereegranskat)abstract
- 1. Binocular summation was studied in human subjects using a batter of vision tests. Two tests assessed detection, another three acuity, one hyperacuity and one pattern recognition. 2. The magnitude of summation was consistent with, or exceeded, the level predicted from quadratic summation for both detection tests. 3. The summation factor was significantly smaller in the resolution tests than in the detection tests. Hyperacuity showed a large individual variation. 4. Spatial filtering of acuity targets did not influence summation. 5. No summation was found in the pattern recognition test. 6. It is argued that the degree of summation is related to the complexity of the visual task. A simple task yields a larger binocular summation than a more complex one. This may be related to the level of processing in the primary visual cortex.
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| 6. |
- Frisén, Lars, 1939
(författare)
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Computerized perimetry: possibilities for individual adaptation and feedback.
- 1988
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Ingår i: Documenta ophthalmologica. Advances in ophthalmology. - 0012-4486. ; 69:1, s. 3-9
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Tidskriftsartikel (refereegranskat)abstract
- Computerized perimetry is often poorly accepted by the tested subjects, presumably because of sparse feedback and lack of adaptation to individual capacity. Several remedies are suggested, including visual response feedback, active correction of erroneous responses, various fixation prompts, and continuous adaptation to current reaction time. Intuitively intelligible result displays are also desirable. A novel format representing threshold level by symbol size may meet this need.
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| 7. |
- Frisén, Lars, 1939
(författare)
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High-pass resolution targets in peripheral vision.
- 1987
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Ingår i: Ophthalmology. - 0161-6420. ; 94:9, s. 1104-8
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Tidskriftsartikel (refereegranskat)abstract
- Visual acuity was measured at 10 degree intervals on the horizontal meridian in two normal subjects, using high-pass spatial frequency filtered test targets in a computer graphics display. The close similarity between detection and recognition thresholds resulted in quick and reliable measurements. Peripheral acuity was proportional to local retinal ganglion cell separation. High-pass targets appear to be nearly ideal for clinical perimetry because of the easy test task and the possibility of interpreting results in terms of numbers of functional neuroretinal channels. The major limitation appears to be a somewhat fuzzy definition of small, circumscribed defects.
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| 8. |
- Frisén, Lars, 1939
(författare)
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Perimetric variability: importance of criterion level.
- 1988
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Ingår i: Documenta ophthalmologica. Advances in ophthalmology. - 0012-4486. ; 70:4, s. 323-30
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Tidskriftsartikel (refereegranskat)abstract
- Perimetry suffers from considerable variability of results. A new technique for estimating individual criterion levels in normal subjects exposes the important role of psychological variables. The analysis depends on features peculiar to acuity perimetry. It can be accommodated in the regular examination. The results can be used to compensate for practice effects in serial examinations and to tighten the range of normal limits. The reduction in variation between normal subjects amounted to 57 per cent.
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| 9. |
- Frisén, Lars, 1939, et al.
(författare)
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Posttraumatic seesaw nystagmus abolished by ethanol ingestion.
- 1986
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Ingår i: Neurology. - 0028-3878. ; 36:6, s. 841-4
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Tidskriftsartikel (refereegranskat)abstract
- We describe a patient who was left with a midchiasmal injury and bitemporal hemianopia after head trauma. Four months later, she developed typical seesaw nystagmus and moderate hydrocephalus. Lumbar punctures did not affect the nystagmus, but a temporary cessation was documented after ingestion of ethanol.
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| 10. |
- Frisén, Lars, 1939
(författare)
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Vanishing optotypes. New type of acuity test letters.
- 1986
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Ingår i: Archives of ophthalmology (Chicago, Ill. : 1960). - 0003-9950. ; 104:8, s. 1194-8
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Tidskriftsartikel (refereegranskat)abstract
- Acuity test letters generated on a television monitor were studied with regard to detection and resolution thresholds, both for the native configurations and after high-pass spatial frequency filtering. Comparisons were made with printed acuity charts of different contrast. Filtering diminished the interval between detection and resolution thresholds. Under some circumstances, a small (1 dB, about 26%) increment in size could make a previously invisible optotype clearly visible, or vice versa. The term vanishing optotype is suggested for acuity targets with this peculiar property. Vanishing optotypes do not seem useful for routine clinical acuity testing, but they may be advantageous, for example, in preferential looking-acuity tests for infants and visual field examinations. Like the present tests, such novel applications can be generated relatively easily on personal computers.
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