In the elderly, speech can be affected by a number of factors unrelated to mental state, including ill-fitting dentures or oral pathology. An increase or decrease in the rate, quantity and/or volume of speech can be associated with mania and depression, respectively. Pressure of speech is characteristic of mania or frontal lobe involvement. In depression, poverty of speech may occur to a degree that the patient appears to be mute or dysphasic, although such a severe impairment in language is more frequently a result of neurodegenerative or cerebrovascular disease than functional illness. Circumstantiality and tangentiality occur in psychosis and mania, but are often related to dementia in the elderly. Similarly, flight of ideas is characteristic of mania but can also occur in frontal lobe syndromes.

Nominal dysphasia is common in the early stages of Alzheimer’s disease when it would normally be associated with at least some degree of memory impairment. Conversely, in primary progressive aphasia (PPA) impairments in language precede deficits in other cognitive domains^12,13. Language deficits in PPA are predominantly expressive and usually associated with loss of fluency; in semantic dementia there is loss of expressive and receptive vocabulary in the presence of fluent but ‘empty’ speech^10,14. Clearly, it is important to ensure that any apparent receptive dysphasia cannot be accounted for by a hearing impairment and that an apparent expressive dysphasia is not in fact the result of dysarthria. Dysphonia is a disorder of phonation due to inability to produce voice sounds using the vocal organs; this is distinct from dysarthria and can occur in Parkinson’s disease, stroke and other organic disorders¹⁵ or as a psychogenic phenomenon¹⁶.

Other abnormalities of speech are suggestive of specific disorders. For example, perseverative speech is almost pathognomonic of organic brain disease, particularly involving the frontal lobes. Verbal stereotypies, mannerisms, echolalia, paraphasia and neologisms also occur in organic (often frontal) syndromes although may also occur in mania and psychosis.

Elderly people may be less likely than younger adults to report sadness or dysphoria. This does not appear to be a cohort effect and has been reported in different generations of older adults¹⁷; whether this will hold true for the current young-old population is not known. The concept of ‘depression without sadness’ has, however, been criticized by some, who suggest that apathy, withdrawal and loss of vigour can represent a depletion or disengagement syndrome that reflects normal age-related changes¹⁸. A similar picture may also result from physical illness due to chronic pain, fatigue and disability. Likewise, the bradykinesia and bradyphrenia of Parkinson’s disease can lead to difficulties in differentiating depressive from physical symptomatology. Apathy, loss of interest and motivation and even abulia may occur in dementia, particularly in subcortical^19,20 and frontotemporal subtypes²¹, and can overlap with or be misinterpreted as depression^22,23. Changes in mood may be also present in the prodromal stages of dementia, before cognitive deficits are apparent²⁴. In established dementia, affective disturbances are common and may present with behavioural changes^25-27.

Given the overlap of symptomatology, it is helpful to pay close attention to the presence of biological features of depression, particularly diurnal mood variation, appetite, early morning waking and anhedonia. Cognitive symptoms of guilt, helplessness and worthlessness are also useful pointers towards a depressive disorder.

Emotional lability can be present in affective disorder and psychosis but can also be a feature of organic syndromes, e.g. cerebrovascular disease²⁸, Parkinson’s disease²⁹ and other brain pathology³⁰, and may be confused with depression. Euphoria is a feature of mania and frontal lobe dysfunction, and may be present in other organic disorders.

Thought Form

As in younger patients, psychotic illness in the elderly can be associated with a broad spectrum of abnormalities of thought form, e.g. circumstantiality, flight of ideas, loosening of associations (from tangentiality through to word salad) and, at the other extreme, thought block. However, apparent thought disorder in the elderly may represent confusion or language disorder as a result of delirium or neurodegenerative illness. Careful attention to the overall picture, including the context of the patient’s presentation and simple cognitive testing, can help to clarify the situation.

Thought Content

Delusions are fixed beliefs out of keeping with an individual’s social, cultural and religious background, which are based on unsound reasoning and are maintained even in the presence of evidence to the contrary. In the elderly, delusions may form part of a psychotic or affective illness but are also common in delirium and dementia. In delirium, delusions are often fleeting and persecutory. In dementia, delusions of theft are common and often relate to misplacement of objects. Well-formed delusional systems are uncommon in dementia but do occur. Delusional misidentification is also common in organic disorder³¹, e.g. patients with dementia may insist that their spouse or even their own reflection in the mirror is an impostor.