1. Screening, Assessment and Diagnosis

Recommendations and/or Clinical Considerations

1.0 Diagnosis of Vascular Cognitive Impairment

1. All individuals with clinically evident stroke, transient ischemic attack (TIA), covert stroke present on brain imaging without history of symptomatic stroke, overt cardiovascular disease, or significant vascular risk factors should be considered at higher risk for vascular cognitive impairment [Strong recommendation; Moderate quality of evidence]. Refer to definitions of VCI, Figure 2 and Figure 3 for additional information.
2. Individuals presenting with signs of cognitive impairment should undergo neuroimaging [Strong recommendation; Low quality of evidence]. 

Refer to Appendix Three for additional information on the presenting signs and symptoms of VCI.

1.1 Screening for Vascular Cognitive Impairment

1. Individuals presenting with stroke or TIA should be screened for any changes in cognition following stroke compared to their pre-stroke cognitive status. [Strong recommendation; Moderate quality of evidence]. Note, changes can be reported by the individual, family members, caregivers or clinicians. Refer to Appendix Three for more information on the presenting signs and symptoms of VCI.
   1. Timing: Individuals who have experienced a stroke or TIA should be screened for cognitive impairment prior to discharge from acute care and inpatient rehabilitation setting [Strong recommendation; Moderate quality of evidence].
2. Ongoing screening should also take place at transition points and follow-up visits with healthcare professionals (e.g., outpatient and community-based healthcare settings) [Strong recommendation; Moderate quality of evidence]. 
3. Individuals who have significant risk factors for vascular cognitive impairment (imaging findings of cerebrovascular disease and/or those with multiple vascular risk factors) and have clinically evident or reported (by the individual or an informant) cognitive, perceptual or functional changes should be screened for vascular cognitive impairment [Strong recommendation; Moderate quality of evidence]. 
   1. Screening should also be considered when a decline in functional abilities is reported or clinically evident [Strong recommendation; Low quality of evidence].
   2. Screening may be initiated by asking the individual and informant (if available) about cognitive or functional changes that could indicate cognitive decline, such as missing medication doses, forgetting medical appointments or other changes in activities of daily living or instrumental activities of daily living.  This should be followed by cognitive and functional assessments as clinically indicated [Strong recommendation; Low quality of evidence]. 
4. When screening for cognition and function, validated screening tools should be used [Strong recommendation; Moderate quality of evidence]. Refer to Appendix Four for more information on validated screening and assessment tools.
5. When screening results are insufficiently informative, inconsistent with functional skills or indicate anticipated safety risks, then referral for formal cognitive, language and/or functional assessments should be considered [Strong recommendation; Low quality of evidence]. Refer to Clinical Consideration Section 1.1, #2 for more information.

Section 1.1 Clinical Considerations

1. There are many validated screening measures for neurocognitive function. Impairment may be indicated by scores that fall outside of standardized norms (based on factors such as age and educational attainment) or by scores that are decreased from the individual’s previous score on the same measure.
2. Screening for VCI is based on inquiring about cognitive or functional declines that may be attributed to cognitive causes. These declines can be reported by the individual or an informant. Examples of functional decline may include missing appointments, difficulty responding to medical instructions, low adherence to medications, safety concerns, difficulties with navigation, financial errors or declines in judgement, or general loss of independence. 
3. Individuals may not be aware of their own symptoms and/or difficulties may not be recognized by family and caregivers; therefore, interviewing both individuals and informants may be valuable.
4. MCI thresholds may be overly sensitive in acute settings and may need to be reassessed in outpatient and rehabilitation settings.
5. Transition points across the continuum may include: 
1. During acute care stay, particularly if cognitive or functional concerns are noted.
2. During rehabilitation in inpatient, outpatient, and home-based settings, according to client progress.
3. Following hospital discharge from the emergency department or inpatient setting to follow-up in an outpatient or community-based healthcare setting, including long term care.
4. The use of different equivalent screening forms when available may help limit practice effects when an individual requires repeated screening across transition points.
6. Measures developed for the detection of dementia may not be sensitive enough to detect milder impairment or they may omit clinically relevant cognitive domains related to VCI.

1.2 Assessment of Vascular Cognitive Impairment

1. Individuals with VCI who demonstrate any cognitive impairments (either clinically, by history, by report of the individual or family, or detected in the screening process), whether associated with history of stroke or not, should undergo more detailed assessment by healthcare professionals with the appropriate expertise in neurocognitive assessment and VCI [Strong recommendation; Moderate quality of evidence]. Refer to Appendix Three for more information on the presenting signs and symptoms of VCI.
2. Assessment of VCI should include the impact of cognitive deficits on function and safety in activities of daily living, driving, instrumental activities of daily living, social, leisure, financial, vocational and/or academic functioning [Strong recommendation; Low quality of evidence]. Refer to Appendix Four for more information on validated screening and assessment tools.
   1. These assessments should be undertaken prior to the individual returning to cognitively demanding activities that may carry a safety risk.  [Strong recommendation; Moderate quality of evidence].
3. Individuals with VCI should also be screened for comorbid conditions that may affect cognition. These may include medical comorbidities, neurodegenerative diseases, sleep disorders, or mood disorders such as depression, anxiety or apathy [Strong recommendation; Moderate quality of evidence]. Refer to Rehabilitation, Recovery and Community Participation module for additional information on post-stroke depression, sleep disorders (Lanctôt et al. 2020). See clinical consideration 2 for additional information.
4. The results of these assessments should be considered to guide selection and implementation of appropriate remedial, compensatory and/or adaptive intervention strategies according to person-centred needs and goals [Strong recommendation; Moderate quality of evidence].

Section 1.2 Clinical Considerations

1. Comorbidities and situational factors: Cognitive performance should be interpreted in the context of potentially confounding clinical factors that may impact interpretation of results, such as communication and sensorimotor deficits (speech and language, vision, hearing), delirium, hypo-arousal or hyper-arousal, neuropsychiatric symptoms (e.g., lability, depression, apathy and anxiety), other medical conditions (e.g., pain, infections) or medications, as well as socio-demographic and individual factors (e.g., language, sex, gender, ethnicity, cultural norms, geography). 
   1. During assessments, especially in acute care settings, environmental factors should be considered, including attempts to maximize privacy, minimize noise and potential distractors, and avoid cues in the room.
   2. Delirium can confound cognitive assessments. New diagnoses (such as stroke) and other reasons for acute care admission, as well as the environment of acute care itself, can trigger or worsen delirium. In the setting of clear delirium, detailed assessment should be deferred; if there are concerns a more subtle delirium could be affecting assessment results, cognitive reassessment over time is helpful.  
   3. Depression has a complex relationship with cognition. Depression can worsen the severity of VCI, VCI may limit non-pharmacological strategies for managing post-stroke depression, and depression in the context of stroke can mimic VCI. 
2. Baseline Function: The breadth and depth of an assessment should consider a person’s individual background, baseline intellectual functioning, education, occupation, social and leisure activities. Task performance can represent a decline and/or be functionally limiting for an individual even when not scoring in a ‘severe’ or ‘impaired’ range on tests. Highest level of education achieved should be recorded and considered in the interpretation of cognitive test scores.
3. Life Stage: Effects of age, life stage or pre-VCI function should be considered when deciding when, what and how to assess. Decisions about what skills to assess should always consider person-centred goals, which may differ by life stages (e.g., school, work, driving, independent living). 
4. Personalization: Individuals with VCI should have personalized management and rehabilitation plans that include a person-centred approach, shared decision-making, culturally appropriate and agreed-upon goals and preferences.
5. Timing: The impacts of VCI can change with time, due to evolving pathology, effects of rehabilitation, and changing life demands. Thus, those who have been identified as being at risk or demonstrating VCI should be screened or assessed at the different stages of care.
6. Cognitive Domains: Cerebrovascular disease can affect any aspect of cognition. Attention, processing speed, and other executive function deficits (skills that help us plan, focus attention, hold and manipulate information in one’s mind, or shift from one task to another) are the most commonly affected domains. Memory (amnestic VCI), language, visuospatial abilities can also be affected.  Domains can be impacted individually or in combination with other domains.
   1. In-depth neuropsychological assessments may include evaluation of a diverse range of cognitive domains including attention, processing speed, executive function, memory, language, and visual-spatial/perceptual function. Assessment should not be limited to the domains in which the individual or informant reports changes. 
   2. There may be focal stroke cognitive syndromes that require specific assessments. 
   3. Attention, speed of processing and executive function each include specific sub-elements or abilities that could be assessed (for example, executive function may include initiation, inhibition, shifting, insight, planning and organization, judgment, problem solving, abstract reasoning and social cognition). Definitions and delineation of the various domains and elements can be found in Evidence-Based Review of Stroke Rehabilitation (EBRSR): Chapter 12 (Saikaley et al. 2022)  
7. Capacity: Professionals should be aware that individuals with VCI may present with impairments in decision-making capacity. When screening or assessing for VCI, consider issues of consent and capacity, both to the assessment itself, and when obtaining collateral information.
8. Assessment Tool Selection: Cognitive evaluation using standardized assessments is important in determining the nature and severity of cognitive impairments, as well as preserved cognitive abilities and strengths. Within a multi-domain assessment, areas of focus may be guided by clinical presentation, history, investigations, and needs or goals of the individual or their caregiver.
   1. There are many validated assessments for neurocognitive function that assess multiple domains. 
   2. Impairment may include scores that fall outside of standardized norms or that differ from the individual’s prior documented functioning.
   3. Therapeutic activities, functional assessments, and/or standardized assessments provide additional information by showing the impact of impairments.
   4. The tools used to assess vascular cognitive impairment may be specific to the clinical question being asked, different settings, geographical areas, professions and timelines encountered along the continuum of care. Consider the validity and standardization of the selected tools with regards to factors such as age, culture, fluency in the language used for the assessment, aphasia, physical function, and education levels.
9. Multiple Assessments: Although screening and assessment at different stages of care is important for guiding diagnosis and management, it is also important to be aware of the potential impact of multiple assessments, on both validity of the test results, and for the individual with VCI (e.g., practice effects, test fatigue). To avoid practice effects, the use of different equivalent assessment forms is recommended when available.
10. Assessments in patients with other neurological deficits: The presence and severity of non-cognitive neurological deficits—including visual field deficits and motor deficits—need to be considered when performing cognitive assessments and understanding the basis of changes in activities of daily living. Additionally, assessing non-language cognitive domains is challenging when aphasia is present. In the setting of other neurological deficits, understanding the impact of changes in cognition may require a careful history, input from an informant, and clinical judgement. In complex cases, formal evaluation by a neuropsychologist and/or repeated assessments may be required.

1.3 Diagnostic Imaging and Laboratory Testing

1. Individuals with suspected VCI should undergo vascular brain imaging with magnetic resonance imaging (MRI) or computed tomography (CT) to evaluate cerebrovascular disease [Strong recommendation; Low quality of evidence].
   
   1. MRI is recommended over CT for investigating VCI when there are no contraindications [Strong recommendation; Moderate quality of evidence]. 
   2. If CT is performed, a non-contrast CT and coronal reformations are recommended to better assess hippocampal atrophy [Strong recommendation; Low quality of evidence] (Smith et al. 2020).
2. Laboratory testing for stroke risk and possible contributing factors to cognitive impairment should include CBC, TSH, B12, calcium, electrolytes, creatinine, ALT, lipid panel, HbA1c [Strong recommendation; Low quality of evidence].

Section 1.3 Clinical Considerations 

1. Vascular-related pathology includes multiple cortical or subcortical infarcts, covert infarcts, strategic infarcts, a small-vessel disease with white matter lesions and lacunae, and brain hemorrhage including microhemorrhages and superficial siderosis.
2. MRI is more sensitive than CT to vascular changes like small brain infarcts and is the modality of choice for describing markers of cerebral small vessel disease and amyloid angiopathy by consensus criteria. MRI can also provide additional information about alternative or concomitant diagnoses, such as focal atrophy patterns associated with neurodegenerative dementias. 
   1. Core imaging sequences include diffusion weighted imaging (DWI), FLAIR, susceptibility scans (either susceptibility-weighted imaging (SWI) or Gradient echo (GRE)), T1-weighted and T2-weighted scans.
   2. MRI with DWI is most sensitive for acute stroke if completed within the first one to two weeks after stroke symptoms or sudden change in cognition or behaviour.
   3. More chronic structural changes associated with VCI, including atrophy, chronic infarcts, cortical microinfarcts, lacunes, white matter disease and microbleeds are assessed using a combination of sequences including: T1 and T2, FLAIR and either SWI or GRE.
3. When MRI is not available or is contraindicated, then imaging with CT is a reasonable consideration. 
4. Imaging, in addition to aiding in diagnosis, can also be used to track changes or progression of the condition over time. 
5. Clinical history and examination findings consistent with stroke can be used as objective evidence of cerebrovascular disease if imaging is not available. 
6. Radiology reports should describe covert cerebrovascular disease according to STRIVE (Duering et al. 2023).
7. White matter hyperintensities (WMHs) of presumed vascular origin should be reported with the use of a validated visual rating scale such as the Fazekas scale for MRI.
8. The threshold of vascular damage—in terms of extent and location—that is required to cause clinical cognitive dysfunction is not clear, and will likely vary between patients due to differing levels of cognitive reserve. A recent study pooling information from more than 2,900 post-stroke brain MRIs found that the left frontal, left temporal, left thalamus, and right parietal regions were strategic locations where infarcts were highly likely to impair cognition. There is a consensus, supported by some evidence from observational studies, that beginning confluent or confluent subcortical WMH, on the Fazekas scale, is sufficient to cause clinical cognitive impairment in many individuals (Staals et al. 2015; Weaver et al. 2021).

Refer to the CCCDTD5 – Vascular Cognitive Impairment guidance for details on imaging procedures for additional information (Smith et al. 2020).

1.4 Diagnostic Criteria for Vascular Cognitive Impairment

1. As defined in these guidelines (see above), vascular cognitive impairment refers to a range of new or worsening cognitive deficits (section 1.1-1.2) attributed to or accelerated by cerebrovascular injury (section 1.3). Diagnosis can be made based on the presence of vascular disease and cognitive impairment as described above (section 1.1-1.3) [Strong recommendation; Low quality of evidence]
2. Standardized criteria can be used to support the diagnosis of vascular cognitive impairment [Conditional recommendation; Low quality of evidence]. 
   
   1. These criteria may include Vascular Behavioral and Cognitive Disorders [VAS‐COG] Society criteria, Diagnostic and Statistical Manual of Mental Disorders [DSM-5], Vascular Impairment of Cognition Classification Consensus Study (VICCS), or the American Heart Association consensus statement [Strong recommendation; Low quality of evidence]. (Smith et al. 2020).