ICD-11 Criteria for Dementia due to Diseases Classified Elsewhere (6D85 ) Coding Note:       This category should never be used in primary tabulation. The codes are provided for use as supplementary or additional codes when it is desired to identify the presence of dementia in diseases classified elsewhere. When dementia is due to multiple aetiologies, code all that apply. 6D85.0          Dementia due to Parkinson disease Dementia due to Parkinson disease develops among individuals with idiopathic Parkinson disease and is characterized by impairment in attention, memory, executive and visuo-spatial functions. Mental and behavioral symptoms such as changes in affect, apathy and hallucinations may also be present. Onset is insidious and the course is one of gradual worsening of symptoms. Coding Note:       This category should never be used in primary tabulation. The codes are provided for use as supplementary or additional codes when it is desired to identify the presence of d