liu.seSearch for publications in DiVA
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Pre-Postoperative 1H-MRS-Changes in Frontal Deep White Matter and the Thalamus in Idiopathic Normal Pressure Hydrocephalus
Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Health Sciences.
Show others and affiliations
(English)Manuscript (preprint) (Other academic)
Abstract [en]

In a previous study we found a significantly decreased N-acetylaspartate (NAA) and total N-acetyl groups (tNA) in the thalamus in patients with idiopathic normal pressure hydrocephalus (iNPH) compared with healthy individuals (HI). No significant difference between the groups could be found in the frontal deep white matter (FDWM). The primary aim of this study was to investigate if these metabolites in the thalamus were normalised after shunt surgery. The secondary aim was to investigate postoperative metabolic changes in FDWM.

Subjects and Methods: Fourteen iNPH-patients, mean age 74 years, and 15 HI, also mean age 74 years, were examined. Assessment of motor scores was performed before and after shunt surgery. Absolute quantitative 1H-MRS (1.5 T, VOI 2.5-3 mL) was performed on the patients in the FDWM and in the thalamus, before and three months after shunt surgery, and also once on the HI. The following metabolites were analysed: tNA, NAA, total creatine (tCr), total choline (tCho), myo-inositol (mIns), glutamate (Glu), and lactate (Lac) concentrations. MRI volumetric calculations of the lateral ventricles were also performed.

Results: At three months postoperatively, we found no significant changes of tNA or NAA in the thalamus. In contrast, in FDWM, there was a significant increase of tCho (p=0.01) and a borderline significant decrease of mIns (p=0.06). 12/14 patients were shunt responders (motor function). Median reduction of the lateral ventricle was 16%. A weak correlation between motor score (MOS) and ventricular reduction was observed.

Conclusion: Normalisation of thalamic tNA and NAA could not be detected postoperatively. The increased tCho and decreased mIns in the FDWM postoperatively might relate to clinical improvement.

Keyword [en]
Normal Pressure Hydrocephalus, Magnetic Resonance Spectroscopy, Postoperative, Thalamus, Frontal lobe
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
URN: urn:nbn:se:liu:diva-84236OAI: oai:DiVA.org:liu-84236DiVA: diva2:558270
Available from: 2012-10-02 Created: 2012-10-02 Last updated: 2014-10-02Bibliographically approved
In thesis
1. Idiopathic Normal Pressure Hydrocephalus: Aspects on Pathophysiology, Clinical Characteristics and Evaluation Methods
Open this publication in new window or tab >>Idiopathic Normal Pressure Hydrocephalus: Aspects on Pathophysiology, Clinical Characteristics and Evaluation Methods
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Introduction. Idiopathic normal pressure hydrocephalus (iNPH) is a condition with enlargement of the cerebral ventricular system and an intracranial pressure (ICP) within normal limits. Cerebrospinal fluid circulation is disturbed but the mechanisms behind the symptoms: gait and balance difficulties, cognitive dysfunction and micturition problems, are as yet mostly unexplained.

Aim. In Studies I and II the aim was to investigate cerebral metabolism in the frontal deep white matter (FDWM) and the thalamus in iNPH using Magnetic Resonance Spectroscopy (MRS) before and after shunt surgery and to compare this with healthy individuals (HI). In Study III the aim was, by use of actigraphy, to measure motor function, energy expenditure and resting/sleeping time in iNPH patients before and after shunt surgery, in comparison with HI. In Study IV the aim was to study postural function using computerised dynamic posturography (CDP) before and after shunt surgery as well as in comparison with HI.

Patients and Methods. In all studies the patients had a neurological examination and baseline bedside assessments of motor, balance and cognitive function were performed. Motor function was assessed using a motor score (MOS) consisting of the following items: 10 metre walk time in seconds and number of steps and TUG time in seconds and number of steps. MOS was considered significant if there was an increase of 5% or more. The HI were also tested for motor, balance and cognitive function. In Study I the patients (n=16) and the HI (n=15) were examined with MRS (absolute quantification) with voxels placed in the thalamus and in FDWM and compared with one another. In Studies III and IV the preoperative results of actigraphy and CDP respectively in patients (Study III n=33; study IV n=35) were compared with the HI: Study III, n=17; Study IV, n=16. The HI performed these examinations twice and the average was calculated. In Study II, 14 patients, and in Studies III and IV, 20 patients underwent shunt surgery and new MRS/actigraphy/CDP examinations were performed three months postoperatively and compared with the preoperative results.

Results. In the patients decreased total N-acetyl compounds (tNA) and N-acetyl aspartate (NAA) were found in the thalamus compared to the HI. No metabolic differences were seen in the FDWM between the groups. Postoperatively there were no metabolic changes in the thalamus but an increased total Choline (tCho) and a borderline significant decrease in myo-inositol (mIns).During the day the patients took fewer steps and had also lower total energy expenditure (TEE) than the HI. There was no difference concerning resting/sleeping time between patients and the HI. Postoperatively there were no differences of either number of steps, TEE or time spent resting or sleeping compared with the preoperative state. Postural function was worse in the patients compared to the HI, this difference being more pronounced in tests measuring vestibular function, where loss of balance (LOB) was frequent. There was only a slight improvement in balance after shunt surgery. A positive response to the shunt operation was seen in 86% in Study II, 85% in Study III and 90% in Study IV.

Conclusions. Our results suggest that the thalamus may be involved in the pathogenesis of iNPH. In contrast to others, we did not find any metabolic abnormalities in the FDWM, nor detect an increment of tNA or NAA postoperatively in the thalamus. The postoperative increase in tCho and borderline decrease in mIns in the FDWM might reflect a state of metabolic recovery since high tCho, a major component of the cell membrane, may be a sign of increased membrane turnover, and a decrease in mIns may indicate diminished gliosis.

The low gait capacity seen in the iNPH patients was not surprising but well that time spent resting/sleeping did not differ from the HI. Another unexpected finding was the unchanged ambulatory activity after shunt surgery despite improvement in a point test to determine capacity to walk a short distance. We believe this could be due to strong habits that are difficult to break and/or shortage of rehabilitation after surgery.

There was a profound postural dysfunction in the patients with many falls, especially in test situations intended to measure vestibular function. This implies that there is a central vestibular disturbance. The discrete improvement in postural function postoperatively was lower than previously reported.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2012. 90 p.
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 1333
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-84243 (URN)978-91-7519-781-4 (ISBN)
Public defence
2012-10-26, Berzeliussalen, Campus US, Linköpings universitet, Linköping, 13:00 (English)
Opponent
Supervisors
Available from: 2012-10-03 Created: 2012-10-02 Last updated: 2012-10-04Bibliographically approved

Open Access in DiVA

No full text

Authority records BETA

Lundin, FredrikTisell, AndersLeijon, GöranDahlqvist Leinhard, OlofLundberg, Peter

Search in DiVA

By author/editor
Lundin, FredrikTisell, AndersLeijon, GöranDahlqvist Leinhard, OlofLundberg, Peter
By organisation
NeurologyFaculty of Health SciencesDepartment of NeurologyRadiation PhysicsDepartment of Radiation Physics UHLDepartment of Medical and Health Sciences
Radiology, Nuclear Medicine and Medical Imaging

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 79 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf