Classified elsewhere
Dementia in Pick's disease

1. The general criteria for dementia (G1–G4) must be met.
2. Onset is slow with steady deterioration.
3. Predominance of frontal lobe involvement is evidenced by two or more of the following:
   1. emotional blunting;
   2. coarsening of social behavior;
   3. disinhibition;
   4. apathy or restlessness;
   5. aphasia
4. In the early stages, memory and parietal lobe functions are relatively preserved.

Dementia in Creutzfeldt-Jakob disease

1. The general criteria for dementia (G1–G4) must be met.
2. There is very rapid progression of the dementia, with disintegration of virtually all higher cerebral functions.
3. One or more of the following types of neurological symptoms and signs emerge, usually after or simultaneously with the dementia.
   1. pyramidal symptoms;
   2. extrapyramidal symptoms;
   3. cerebellar symptoms;
   4. aphasia;
   5. visual impairment.

Comments
An akinetic and mute state is the typical terminal stage. An amyotrophic variant may be seen, where the neurological signs precede the onset of the dementia. A characteristic electroencephalogram (periodic spikes against a slow and low voltage background), if present in association with the above clinical signs, increases the probability of the diagnosis. However, the diagnosis can be confirmed only by neuropathological examination (neuronal loss, astrocytosis, and spongiform changes). Because of the risk of infection, this should be carried out only under special protective conditions.
Dementia in Huntington's disease

1. The general criteria for dementia (G1–G4) must be met.
2. Subcortical functions are affected first and dominate the picture of dementia throughout; subcortical involvement is manifested by slowness of thinking or movement and personality alteration with apathy or depression.
3. There are involuntary choreiform movements, typically of the face, hands, or shoulders, or in the gait. The patient may attempt to conceal them by converting them into a voluntary action.
4. There is a history of Huntington's disease in one parent or a sibling, or a family history that suggests the disorder.
5. There are no clinical features that otherwise account for the abnormal movements.

Comments
In addition to involuntary choreiform movements, there may be development of extrapyramidal rigidity or of spasticity with pyramidal signs.
Dementia in Parkinson's disease

1. The general criteria for dementia (G1–G4) must be met.
2. A diagnosis of Parkinson's disease has been established.
3. None of the cognitive impairment is attributable to antiparkinsonian medication.
4. There is no evidence from the history, physical examination, or special investigations for any other possible cause of dementia, including other forms of brain disease, damage, or dysfunction (e.g., cerebrovascular disease, HIV disease, Huntington's disease, normal pressure hydrocephalus), a systemic disorder (e.g., hypothyroidism, vitamin B₁₂ or folic acid deficiency, hypercalcemia), or alcohol or drug abuse.

If criteria are also fulfilled for dementia in Alzheimer's disease with late onset, that category should be used in combination with Parkinson's disease.
Dementia in human immunodeficiency virus (HIV) disease

1. The general criteria for dementia (G1–G4) must be met.
2. A diagnosis of HIV infection has been established.
3. There is no evidence from the history, physical examination, or special investigations for any other possible cause of dementia, including other forms of brain disease, damage, or dysfunction (e.g., Alzheimer's disease, cerebrovascular disease, Parkinson's disease, Huntington's disease, normal pressure hydrocephalus), a systemic disorder (e.g., hypothyroidism, vitamin B₁₂ or folic acid deficiency, hypercalcemia), or alcohol or drug abuse.

Dementia in other specified diseases classified elsewhere
Dementia can occur as a manifestation or consequence of a variety of cerebral and somatic conditions. To specify the etiology the ICD-10 code for the underlying condition should be added.