Criteria

Revised criteria for the clinical diagnosis of probable and possible DLB: fourth report of the DLB consortium[1]

Clinical signs and symptoms are weighted as core or supportive, and biomarkers as indicative or supportive, based on their diagnostic specificity and the volume of good quality evidence available. Although carrying less diagnostic weight, supportive items are often valuable in clinical decision-making, acting as signposts to, or adding evidence for, a DLB diagnosis. The previous category of suggestive features is no longer used and those items, namely rapid eye movement (REM) sleep behaviour disorder (RBD), severe antipsychotic (neuroleptic) sensitivity, and low dopamine transporter imaging, have been reassigned in the new scheme.

Core clinical features (the first three typically occur early and may persist throughout the course):

  • Fluctuating cognition with pronounced variations in attention and alertness.

  • Recurrent visual hallucinations that are typically well formed and detailed.

  • RBD, which may precede cognitive decline.

  • One or more spontaneous cardinal motor features of parkinsonism: these are bradykinesia (defined as slowness of movement and decrement in amplitude or speed), rest tremor, or rigidity.

Supportive clinical features:

  • Severe sensitivity to antipsychotic agents; postural instability; repeated falls; syncope or other transient episodes of unresponsiveness; severe autonomic dysfunction (e.g., constipation, orthostatic hypotension, urinary incontinence); hypersomnia; hyposmia; hallucinations in other modalities; systematised delusions; apathy, anxiety, and depression.

Indicative biomarkers:

  • Reduced dopamine transporter uptake in basal ganglia demonstrated by single-photon emission computed tomography (SPECT) or positron emission tomography (PET).

  • Abnormal (low uptake) 123-iodine-metaiodobenzylguanidine (MIBG) myocardial scintigraphy.

  • Polysomnographic confirmation of REM sleep without atonia.

Supportive biomarkers:

  • Relative preservation of medial temporal lobe structures on CT/magnetic resonance imaging scan.

  • Generalised low uptake on SPECT/PET perfusion/metabolism scan, reduced occipital activity, and the cingulate island sign on fluorodeoxyglucose-PET imaging.

  • Prominent posterior slow-wave activity on EEG with periodic fluctuations in the pre-alpha/theta range.

Probable DLB can be diagnosed if:

  1. Two or more core clinical features of DLB are present, with or without the presence of indicative biomarkers, or

  2. Only one core clinical feature is present, but with one or more indicative biomarkers.

Probable DLB should not be diagnosed on the basis of biomarkers alone.

Possible DLB can be diagnosed if:

  1. Only one core clinical feature of DLB is present, with no indicative biomarker evidence, or

  2. One or more indicative biomarker is present but there are no core clinical features.

DLB is less likely:

  1. In the presence of any other physical illness or brain disorder including cerebrovascular disease, sufficient to account in part or in total for the clinical picture, although these do not exclude a DLB diagnosis and may serve to indicate mixed or multiple pathologies contributing to the clinical presentation, or

  2. If parkinsonian features are the only core clinical feature and appear for the first time at a stage of severe dementia.

DLB should be diagnosed when dementia occurs before or concurrently with parkinsonism. The term Parkinson's disease dementia (PDD) should be used to describe dementia that occurs in the context of well-established Parkinson's disease. In a practice setting, the term that is most appropriate to the clinical situation should be used, and generic terms such as Lewy body disease are often helpful. In research studies in which distinction needs to be made between DLB and PDD, the existing 1-year rule between the onset of dementia and parkinsonism continues to be recommended.

Diagnostic and statistical manual of mental disorders, 5th ed., text revision (DSM-5-TR) criteria for major or mild neurocognitive disorder with Lewy bodies[3]​​[4]

A. The criteria are met for major or mild neurocognitive disorder.

  1. Major neurocognitive disorder: evidence of significant cognitive decline from a previous level of performance in one or more cognitive domains that interferes with independence in everyday activities. The cognitive deficits do not occur exclusively in the context of a delirium and are not better explained by another mental disorder.

    1. Specify severity:

      1. Mild: difficulties with instrumental activities of daily living (e.g., housework, managing money).

      2. Moderate: difficulties with basic activities of daily living (e.g., feeding, dressing).

      3. Severe: fully dependent.

    2. Specify:

      1. With agitation: if the cognitive disturbance is accompanied by clinically significant agitation.

      2. With anxiety: if the cognitive disturbance is accompanied by clinically significant anxiety.

      3. With mood symptoms: if the cognitive disturbance is accompanied by clinically significant mood symptoms (e.g., dysphoria, irritability, euphoria).

      4. With psychotic disturbance: if the cognitive disturbance is accompanied by delusions or hallucinations.

      5. With other behavioural or psychological disturbance: if the cognitive disturbance is accompanied by other clinically significant behavioural or psychological disturbance (e.g., apathy, aggression, disinhibition, disruptive behaviours or vocalisations, sleep or appetite/eating disturbance).

  2. Mild neurocognitive disorder: evidence of modest cognitive decline from a previous level of performance in one or more cognitive domains that does not interfere with independence in everyday activities. Greater effort, compensatory strategies, or accommodation may be required to preserve independence in complex instrumental activities of daily living (e.g., paying bills, managing medications). The cognitive deficits do not occur exclusively in the context of a delirium and are not better explained by another mental disorder.

    1. Specify:

      1. Without behavioural disturbance: if the cognitive disturbance is not accompanied by any clinically significant behavioural disturbance.

      2. With behavioural disturbance (specify disturbance): if the cognitive disturbance is accompanied by a clinically significant behavioural disturbance (e.g., apathy, agitation, anxiety, mood symptoms, psychotic disturbance, or other behavioural symptoms).

B. The disorder has an insidious onset and gradual progression.

C. The disorder meets a combination of core diagnostic features and suggestive diagnostic features for either probable or possible neurocognitive disorder with Lewy bodies.

For probable major or mild neurocognitive disorder with Lewy bodies, the individual has two core features, or one suggestive feature with one or more core features.

For possible major or mild neurocognitive disorder with Lewy bodies, the individual has only one core feature, or one or more suggestive features.

  1. Core diagnostic features:

    1. Fluctuating cognition with pronounced variations in attention and alertness.

    2. Recurrent visual hallucinations that are well formed and detailed.

    3. Spontaneous features of parkinsonism, with onset subsequent to the development of cognitive decline.

  2. Suggestive diagnostic features:

    1. Meets criteria for RBD.

    2. Severe neuroleptic sensitivity.

D. The disturbance is not better explained by cerebrovascular disease, another neurodegenerative disease, the effects of a substance, or another mental, neurological, or systemic disorder.

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