Cognitive impairment and functional outcome after stroke associated with small vessel disease
- Correspondence to: Dr V C T Mok Department of Medicine, Prince of Wales Hospital, Shatin, The Chinese University of Hong Kong, Hong Kong, China;
- Received 25 March 2003
- Accepted 7 September 2003
- Revised 20 July 2003
Objectives: Although stroke associated with small vessel disease (SSVD) can induce both motor and cognitive impairment, the latter has received less attention. We aimed to evaluate the frequency of the varying severity levels of cognitive impairment, the determinants of severe cognitive impairment, and the association of cognitive impairment with functional outcome after SSVD.
Methods: Consecutive patients admitted to hospital because of SSVD were assessed at 3 months after stroke. We performed a semi-structured clinical interview to screen for cognitive symptoms. Severity of cognitive symptoms was graded according to the Clinical Dementia Rating Scale (CDR). Performance on psychometric tests (Mini-Mental State Examination, Alzheimer’s Disease Assessment Scale (cognition subscale), Mattis Dementia Rating Scale (initiation/perseverence subscale; MDRS I/P)) of patients of different CDR gradings was compared with that of 42 healthy controls. Basic demographic data, vascular risk factors, stroke severity (National Institute of Health Stroke Scale; NIHSS), pre-stroke cognitive decline (Informant Questionnaire on Cognitive Decline in the Elderly; IQCODE), functional outcome (Barthel index; BI), Instrumental Activities Of Daily Living; IADL), and neuroimaging features (site of recent small infarcts, number of silent small infarcts, white matter changes) were also compared among the groups. Regression analyses were performed to find predictors of severe cognitive impairment and poor functional outcome.
Results: Among the 75 included patients, 39 (52%) complained of cognitive symptoms. The number of patients in each CDR grading was as follows: 39 (52%) had a CDR of 0, 26 (34.7%) had a CDR of 0.5, 10 (13.3%) had a CDR of ⩾1. Pre-stroke IQCODE and previous stroke predicted CDR⩾1. The NIHSS was associated with more impaired BI. The NIHSS and MDRS I/P contributed most to impaired IADL.
Conclusions: Half of the patients with SSVD complained of varying severity of cognitive problems 3 months after stroke. Pre-stroke cognitive decline and previous stroke predict severe cognitive impairment post stroke. Stroke severity and executive dysfunction contribute most to a poor functional outcome.
- BI, Barthel Index
- CDR, Clinical Dementia Rating Scale
- CT, computed tomography
- IADL, Instrumental Activities Of Daily Living
- IQCODE, Informant Questionnaire on Cognitive Decline in the Elderly
- MDRS I/P, Mattis Dementia Rating Scale (initiation/perseverence subscale)
- MRA, magnetic resonance angiography
- MRI, magnetic resonance imaging
- NIHSS, National Institute of Health Stroke Scale
- SSVD, stroke associated with small vessel disease
- TCD, transcranial Doppler
- TIA, transient ischaemic attack
- WMC, white matter changes
Competing interests: none declared