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Biomedical subjects

M Jehkonen

Publications and source records attributed to M Jehkonen.

11 recordsLinked to original sources
PubMed2007

A review of executive functions in obstructive sleep apnea syndrome.

OBJECTIVES: To provide an update on recent research concerning obstructive sleep apnea syndrome (OSAS) and executive functions. METHODS: A systematic review was carried out on reports drawn from MEDLINE and PSYCHLIT (January 1990-December 2005) and identified from lists of references in these reports. The selection criteria were met by 40 articles. RESULTS: The sample sizes in the reviewed studies varied widely and consisted mostly of selected groups. Most patient samples were heterogeneous in terms of the severity of OSAS. Executive functions were generally assessed with standardized test methods. Half of the studies assessed executive functions using only one or two tests. The most defected domains of executive functions were working memory, phonological fluency, cognitive flexibility, and planning. Continuous positive airway pressure (CPAP) treatment improved performance times, cognitive flexibility, and planning. Deficits in working memory and phonological fluency persisted. CONCLUSIONS: Executive functions are the most defected cognitive domain in OSAS. Previous studies are affected by the heterogeneity of patient samples and the definitions of the domains of executive functions. Executive functions in OSAS should be assessed with a standardized neuropsychological test battery including assessments of different domains of executive functions. More research is needed on the efficiency of CPAP treatment on executive dysfunctions.

Continuous Positive Airway Pressure↗
PubMed2006

Anosognosia after stroke: assessment, occurrence, subtypes and impact on functional outcome reviewed.

PURPOSE: This review provides an update on recent research findings concerning the methods used in the assessment of anosognosia, the occurrence and subtypes of anosognosia, the association between anosognosia and neglect, and the impact of anosognosias on functional outcome. METHODS: A systematic review covering the period from 1995 to 2005 was carried out on reports drawn from electronic databases (MEDLINE, PSYCHLIT) and identified from the references in these reports. Twenty-seven articles met the selection criteria. RESULTS: The results of this review are in line with previous findings in the following respects: anosognosia was more often associated with right hemisphere damage, neglect and anosognosia co-occurred, and anosognosia had predictive value on poor functional outcome. The variation in the methods used in the assessment of anosognosia, patient samples and assessment times influence the occurrence rates and the predictive value of anosognosia, which might undermine the generalizability of the results. CONCLUSIONS: More homogeneous patient samples and consistency in the assessment methods and evaluation times would facilitate comparisons of the occurrence and the impact of anosognosia on functional outcome. New methods need to be developed for the assessment of anosognosia. These new methods should take account of the subtypes of anosognosia both at verbal and at non-verbal levels.

Agnosia↗
PubMed2006

Impact of neglect on functional outcome after stroke: a review of methodological issues and recent research findings.

PURPOSE: This study provides an update on recent research findings concerning neglect and its impact on functional outcome. The review covers studies published during the past ten years. METHODS: A systematic review was carried out on reports drawn from electronic databases (MEDLINE and PSYCHLIT, January 1996 - August 2005) and identified from the lists of references in these reports. Unpublished reports, articles in other than the English language, and studies with non-human and non-adult subjects were excluded. The selection criteria were met by 26 articles. RESULTS: 15 of the 26 studies recruited heterogeneous patient groups (patients with right and left and/or unspecified lesions). The results from homogeneous groups (right hemisphere patients) were more consistent, emphasizing neglect as an independent predictor of functional outcome. Studies with homogeneous patient groups used consecutive series of patients, standardized measures of neglect, and a broader concept of functional outcome (both motor and cognitive items) than those with heterogeneous patient groups. Follow-ups longer than one year were very rare. CONCLUSIONS: Neglect has a significant negative impact on functional outcome, either as an independent predictive factor or in connection with other variables. The results, however, are inevitably affected by differences in patient samples and in the methods used in assessing neglect and functional outcome. Research focusing on homogeneous patient groups and especially on left hemisphere patients is needed. Neglect should be assessed with a standardized test battery rather than a single test, and functional outcome should be measured with scales consisting of cognitive, social and motor items. Also longer follow-ups are needed to verify the long-term functional outcome of neglect patients.

Aged↗
PubMed2001

Predictors of discharge to home during the first year after right hemisphere stroke.

OBJECTIVES: The aim of this study was to explore predictive factors of the length of hospital stay at the acute stage of right hemisphere stroke. Special attention was paid to the possible role of anosognosia for hemiparesis and anosognosia for neglect in this prediction. PATIENTS AND METHODS: A consecutive series of 57 patients having their first right hemisphere stroke were examined at the acute phase. Forty-nine patients were included in this study and followed-up for 12 months. The examinations were conducted within 2 weeks of onset. The outcome variable was the time (days) from stroke to discharge to home. The predictors were age, gender, size of infarct, neglect, hemiparesis, verbal memory, unawareness of illness, anosognosia for neglect, anosognosia for hemiparesis and presence of a relative at home. RESULTS: Hemiparesis and unawareness of illness lengthened the duration of the hospital stay, the presence of a relative reduced it. Neglect was the best single predictor of poor outcome, but it had no additional value in the combination of the three predictors above. Neither anosognosia for hemiparesis nor anosognosia for neglect were important predictors. CONCLUSION: Hemiparesis, unawareness of illness and presence of a relative at home were the best predictors of the time from right hemisphere stroke to discharge to home.

Activities of Daily Living↗
PubMed2000

Volumetric measurements of right cerebral hemisphere infarction: use of a semiautomatic MRI segmentation technique.

The applications of a new segmentation software, Anatomatic, in the evaluation of volumetric measurements of brain infarctions and the new Medimag 3D software in the evaluation of 3D image representation of infarctions are described. These programs are applied to magnetic resonance imaging. The aim of this study is to evaluate the use of these software packages in making accurate volumetric measurements in 40 patients with right cerebral infarctions, in determining the correlations between the quantitated lesions and neurological/neuropsychological dysfunctions and in creating realistic 3D views of the infarctions. Using Anatomatic, reproducible infarction volumes were achieved with ease and within a reasonably fast time. Medimag helped achieve realistic 3D representations of the infarctions. When compared, the semiautomatic segmentation proved to be much faster and yielded higher infarction volumes than the manual segmentation technique. Significantly positive correlations between the infarction volumes and neurological dysfunctions and neuropsychological deficit (neglect) helped to explain the effect of volumes on the clinical status of the patients.

Adult↗
PubMed2000

Visual neglect as a predictor of functional outcome one year after stroke.

OBJECTIVE: The aim was to study the role of visual neglect in acute right hemisphere brain infarct as a predictor of poor functional outcome during the first year after stroke. In particular, we were interested in the additional value of neglect measures besides hemiparesis, hemianopia, cognitive deficits and age. PATIENTS AND METHODS: A consecutive series of 57 patients with a neuroradiologically verified right hemisphere infarct was examined within 10 days of the stroke. Fifty patients were followed up for 1 year. Neglect was measured with the Conventional and the Behavioural subtests of the Behavioural Inattention Test (BITC and BITB, respectively). The predictors were determined at the 10-day examination. Functional outcome was assessed 3, 6 and 12 months after the onset with the Frenchay Activities Index. RESULTS: Neglect in BITB was the best single predictor, which together with high age formed the best combination of predictors for poor functional outcome at each follow-up. Hemiparesis was also included in this prediction model at the 3-month follow-up, but hemianopia, BITC, or visuoconstructional and memory deficits showed no additional predictive value. However, neglect usually recovered soon. When neurological and cognitive deficits were assessed at the same time as the outcome, hemiparesis rather than neglect was the strongest correlate of poor outcome. CONCLUSION: Neglect in acute stroke is an important predictor of poor functional recovery. Residual neglect, which could be compensated in the follow-up tests, may nevertheless restrict patients' real-life activities and hobbies.

Acute Disease↗
PubMed2000

Unawareness of deficits after right hemisphere stroke: double-dissociations of anosognosias.

OBJECTIVES: The aim was to study whether anosognosia for hemiparesis, anosognosia for neglect and general unawareness of illness double-dissociate, indicating that anosognosias are specific and independent impairments of awareness. On the other hand, anosognosias may be associated with one another and with general cognitive dysfunction, which decreases awareness of deficits. The persistence and predictive value of anosognosias was examined during a 1-year follow-up. PATIENTS AND METHODS: Fifty-seven consecutive patients with acute right hemisphere infarction underwent neurological and neuroradiological examinations, neuropsychological testing and an interview 10 days, 3 months and 1 year after onset. RESULTS: Anosognosia for neglect and anosognosia for hemiparesis double-dissociated, as did unawareness of illness and anosognosia for neglect. Patients showing unawareness of illness or anosognosia for neglect and anosognosia for hemiparesis had poorer orientation and verbal memory than patients who were aware of these defects. Unawareness of illness and anosognosia for hemiparesis disappeared during 3-month follow-up. CONCLUSION: Double-dissociations demonstrate that anosognosias for different defects are independent and specific impairments of awareness, although general cognitive disorder may also reduce awareness of defects. Unawareness of illness and anosognosia for hemiparesis disappear rapidly and can hardly be direct causes of poor long-term recovery. However, transient anosognosia may be associated with persistent disorders which result in poor outcome.

Aged↗
PubMed2000

Low plasma antioxidant activity is associated with high lesion volume and neurological impairment in stroke.

BACKGROUND AND PURPOSE: Oxidative stress is probably involved in neuronal damage induced by ischemia-reperfusion. The purpose of this study was to assess the role of antioxidant activity in cerebral ischemic stroke. METHODS: Antioxidant activity of blood plasma and cerebrospinal fluid was assessed in 22 patients with cerebral hemisphere infarction that was verified and quantified by MRI. RESULTS: Low total peroxyl radical trapping potential of plasma, but not of cerebrospinal fluid, was associated with high lesion volume and high neurological impairment assessed by scores on NIH Stroke Scale, Barthel Index, and Hand Motor Score tests. The plasma concentrations of ascorbic acid, alpha-tocopherol, and protein thiols were also associated with the degree of neurological impairment. CONCLUSIONS: These data suggest that the antioxidant activity of plasma may be an important factor providing protection from neurological damage caused by stroke-associated oxidative stress.

Adult↗
PubMed1998

Cortical silent period evoked by transcranial magnetic stimulation in ischemic stroke.

OBJECTIVES: Transcranial magnetic stimulation (TMS) of the motor cortex produces motor evoked potentials (MEPs). Besides this excitatory response, TMS has inhibitory effects. When TMS is performed during voluntary muscle contraction, the MEP is followed by a pause in electromyographic activity (cortical silent period, SP). The aim of this study was to evaluate the clinical usefulness of the SP. METHODS: We studied SP changes in 50 patients with acute hemispheric brain infarction. A stimulator with a round coil and a fixed intensity of 90% of maximum was used to evoke MEPs. RESULTS: SP was elicited on the affected side in 29 of the 50 patients. The mean SP duration was markedly longer on the affected side in the patient group. There were no significant differences between left and right sides in the means of the MEP amplitude ratio (amplitude related to corresponding amplitudes to peripheral electric stimulation) and MEP latencies in the patient group. Prolonged SP was found in 25 of the 29 patients (86%) whereas only 4 (14%) had abnormalities in MEP latency or amplitude ratio. The mean SP duration was significantly prolonged also in a subgroup of 14 patients with normal hand function. CONCLUSIONS: The SP measurement is an easily performed and sensitive method to detect even subclinical disturbances in motor system function in ischemic stroke.

Adult↗
PubMed1997

Auditory sustained attention is a marker of unilateral spatial neglect.

The relationships between performance on a non-spatially-lateralized measure of sustained attention and spatial bias on tests sensitive to unilateral neglect were considered in a group of 44 patients with right hemisphere lesions following stroke. As predicted from earlier studies showing a strong association between unilateral spatial neglect and sustained attention, performance on a brief and monotonous tone-counting measure formed a significant predictor of spatial bias across a variety of measures of unilateral visual neglect. This study provides further evidence for a very close link between two attentional systems hitherto regarded as being quite separate, namely a spatial attention system implicated in unilateral neglect and a sustained attention system. A close connection between these two systems was predicted by Posner, who argued that the right hemisphere-dominant sustained attention system provides a strong modulatory influence on the functioning of the lateralized posterior attention system.

Acoustic Stimulation↗