Dementia (dementia) is a group of acquired clinical syndromes characterized by multiple cognitive deficits of sufficient magnitude to affect the occupational and social activities of the patient. Dementia can be of single or multiple etiology. Depending on the etiology and pathogenesis, the many signs and symptoms of these cognitive and non-cognitive deficits or disorders will also appear in different orders and combinations and constitute different clinical syndromes. The course and prognosis of dementia varies depending on the etiology, progressive or resting, and can also be somewhat remitting.
Etiology of dementia.
(i) Neurodegenerative dementias (NDD).
(1) Alzheimer’s type dementia.
(2) Frontotemporal dementias.
(3) Lewy body dementia.
(4) Posterior cortical dementia
(ii) Neurodegenerative diseases with dementia.
(1) Parkinson’s disease.
(2) Huntington’s disease.
(3) Corticobasal ganglion degeneration.
(4) Amyotrophic lateral sclerosis-dementia.
(3) Vascular dementia.
(4) Dementia secondary to other diseases.
Common diseases are.
Normal cranial pressure hydrocephalus; craniocerebral trauma. Brain tumors; ischemic and hypoxic encephalopathy.
Infectious diseases.
Including chronic meningitis, tuberculosis, mycobacteria, parasites; HIV infection; Prion’s disease such as Creutzfeldt-Jacob disease and new variant CJD; neurosyphilis; Whipple’s disease; Lyme disease; endocrine disorders: including hypothyroidism, parathyroid and pituitary disorders, and islet cell tumors. Nutritional deficiencies: including VitB12 deficiency, folic acid deficiency, and VtB deficiency. Metabolic disorders: electrolyte disorders, renal and hepatic failure; Wilson’s disease; colloid-vascular inflammation: systemic lupus erythematosus; temporal arteritis; rheumatic vasculitis; sarcoidosis; granulomatous vasculitis; pulmonary disorders and others: e.g. obstructive sleep apnea syndrome; chronic obstructive pulmonary disorders; limbic lobe encephalitis; radiation-induced dementia; dialysis encephalopathy. Hypothyroidism and VitB12 and folic acid deficiency should be excluded as routine tests.
Persistent dementia induced by dementia-causing substances has the following three main categories.
①Drugs: antiepileptic drugs, sedatives, sleeping pills, anti-anxiety drugs and intrathecal aminopterin (methotrexate).
② poisoning: CO poisoning, toluene, lead poisoning, mercury poisoning, organophosphorus pesticide poisoning and industrial solvent and adhesive poisoning.
③Alcohol.
Psychogenic pseudo-dementia :
Mainly depression, depression can be manifested as pseudo-dementia confused with AD causing diagnostic difficulties, while the most common manifestation of non-cognitive dysfunction in AD is depression, and the differential diagnosis between the two is even more difficult.
Clinical features.
(a) General symptoms of dementia.
1, cognitive function deficits.
Memory impairment is the prominent early symptom, especially in Alzheimer type dementia, patients mostly show both prograde and retrograde forms of amnesia, and it is difficult to determine the sequence of their appearance. Common manifestations are loss of valuable objects (such as wallets, keys and cell phones), forgetting food steaming on the stove, forgetting appointments and recent events, inability to remember years, months, days, or even seasons, and getting lost in familiar surroundings. Late onset memory impairment may even include forgetting vocational skills, schooling, birthdays, not recognizing family members, or even losing one’s name.
Speech impairment or aphasia.
This may manifest as difficulty naming people or objects. Speech may become unclear or hollow, long and cumbersome, with excessive use of vague words and pronouns. Comprehension of speech, writing and repetition disorders are also often present. In the late stages, the patient becomes reticent and less verbal, or speech metamorphosis, characterized by imitation of speech (echolalia), imitating all sounds heard or repeating speech, repeating again and again the sounds or utterances heard.
Disuse is the inability to perform motor activity operations in the absence of motor and sensory impairment with normal comprehension, and is characterized by ideational disuse, in which the patient is unable to imitate the use of appliances (e.g., hair combing movements, etc.), or operate known actions (e.g., waving hands, goodbye) with gestures. This may also manifest as impairments in dressing, drawing, and cooking. Patients may also be asked to perform skillful motor manipulations, such as brushing teeth, copying a drawing of two crossed pentagons, putting together blocks, and arranging a figure with a matchstick to test spatial construction skills.
Patients with loss of recognition have normal vision, but lose the ability to recognize objects (e.g., chairs and pencils). This progresses to the inability to recognize family members or even the patient’s own reflection in the mirror. Tactile loss can also occur, with the patient unable to recognize objects placed in the hand (such as coins or keys) by touch alone.
Executive functioning disorder.
This is a disorder in the performance of more complex tasks or in the completion of more complex behavioral activities. This includes abstract thinking, design planning, initiation, sequential functioning, monitoring correction, and termination. People with abstract thinking disorders have difficulty processing new things and avoid tasks and activities in life that require new and complex information.
The degree of cognitive dysfunction is required for the diagnosis.
To diagnose dementia, cognitive dysfunction must be at the following levels.
①These cognitive impairments must significantly affect the patient’s ability to function in daily, social and occupational activities such as going to school, working, shopping, dressing, showering, handling money, and other daily activities.
② their cognitive decline must be below the original level to be diagnosed
2. Non-cognitive dysfunction.
Spatial awareness impairment.
This is manifested by spatial orientation, such as impairment in recognizing locations and positions, and difficulty performing spatial awareness activities.
Impaired judgment and foresight.
Patients are not aware of their memory and other cognitive dysfunctions and their prognosis, which may be manifested by unrealistic overestimation of their abilities or status; behaviors and activities in behavior and work that are incompatible with their intelligence, learning, skills, material and financial resources, as well as their position, social status and identity
Disinhibited behavior.
Includes anachronistic excessive wit and joking, neglect of personal grooming and hygiene, inappropriate and excessive displays of closeness to living people, and disregard for rules, regulations, and manners learned by social and occupational traditions, seen especially in frontotemporal dementia.
Speech, gait and movement.
Patients with dementia may have gait-motor abnormalities and frequent falls. Slurred speech, extrapyramidal and pyramidal signs and symptoms are particularly seen in vascular dementia, Lewy body dementia, and dementia combined with Parkinson’s disease and ALS.
Mental and behavioral disorders.
Mental and behavioral disorders are prominent symptoms of dementia. Common symptoms include anxiety, depression, mood disorders, and psychiatric and behavioral abnormalities. Mental abnormalities include hallucinations, delusions of persecution are the most common, and some patients become particularly agitated or have other behavioral abnormalities at night, called “sundowning”. Behavioral abnormalities are highly variable and include wandering, agitation, restlessness, aggressive behavior, mostly unwarranted verbal behavior or actions that attack and harass others, and morbid searching and gathering of valuable or worthless objects, ranging from currency and paper to discarded beverage bottles and ashes. In addition, there may be abnormal eating and sexual behavior and sleep disturbances.
3. Delirium.
Delirium is often present in patients with dementia. If the symptoms of dementia only appear during the delirium, the diagnosis of dementia cannot be established, but delirium can appear additionally in patients with pre-existing dementia, and this coexistence should be given extra attention in the diagnosis and treatment.