impairment of visual acuity is typical of advancing age and is frequently associated with non‐neurological causes (e.g. cataract, glaucoma). Presbyopia, a decline in unaided near vision, is highly prevalent in older people and manifests as blurred vision at normal reading distances and eyestrain or headaches after reading or doing close‐up activities. With ageing, pupil size and reactivity tend to decline, and changes in saccadic movements (e.g. increased latency, decreased frequency, amplitude, peak velocity, and mean velocity) are commonly observed.44 Tracking eye movements (or pursuits) appear less smooth with possible saccadic intrusions. The angles of vertical gaze (especially upward) are frequently symmetrically reduced in older people.45 Convergence is also often impaired.45
Hearing
Hearing loss is a common sensory impairment in older people and may have profound functional implications by interfering with communication and leading to social isolation. Accordingly, simple hearing assessments (e.g. the whisper voice test46) should be incorporated in the neurological examination and can help determine whether the individual needs a comprehensive evaluation (i.e. audiometry, tympanometry). Typically, age‐related hearing impairment is more marked at higher frequencies and characterized by a diminished ability to understand speech in noisy environments and localize sounds.
Taste and smell
Disturbances in the ability to smell and taste are common in older people.47 They can manifest as frank losses of function (i.e. hyposmia/anosmia, hypogeusia/ageusia), distortions, or hallucinations. Deficits in such chemical senses reduce the pleasure from food, represent risk factors for nutritional and immune deficiencies, and limit adherence to healthy dietary regimens.
Sensation
An impaired vibration sense in the big toe is observed in approximately one‐third of presumed healthy people over age 60.48 Numbness, paraesthesia, and dysesthesia are often complained of by older people. Conversely, joint position sense, pain perception, and light touch are less frequently impaired. The decline of lower‐limb proprioception is associated with relevant balance issues and, consequently, with a higher risk of falls.49
Reflexes
By the age of 80, almost one‐third of healthy people have lost their ankle jerk reflexes.48 Knee, triceps, and biceps jerks are mostly maintained. Older individuals can exhibit ‘primitive’ reflexes, a group of behavioural motor responses that are found in normal early development and are subsequently inhibited, but that may be released from inhibition during the ageing process and/or by cerebral damage.50 They include the palmomental reflex (i.e. ipsilateral chin movement evoked by scratching the palm along the thenar eminence), snout reflex (i.e. lips pucker in response to gentle pressure over the nasal philtrum), sustained glabella reflex (i.e. continuous blinking reaction elicited by repetitive light tapping of the glabella with no habituation), and grasp reflex (i.e. handclasp in response to distal ascending pressure on the palm). The presence of primitive reflexes does not reflect specific neuropathological modifications and does not predict the trajectory of future decline (e.g. in cognition) over time.51
Posture, gait, and balance
These functions should be carefully assessed, as they strongly influence the individual’s risk of falls and loss of independence. Various gait parameters can change in the older person due to multifactorial declines in different domains (e.g. sensory loss, motor impairment, cardiorespiratory insufficiency, cognitive deficit, and affective disturbances).52 Walking speed is frequently reduced, stride length tends to decrease, and difficulty emerges in navigating inclines and declines.41 The tandem ability is often reduced, and the need for prolonged double‐limb support time and a slight widening of the base of support is commonly observed.53 Postural changes mostly consist of a slightly stooping of the trunk. Various functional performance tests (e.g. the Short Physical Performance Battery 54), easy to use in daily practice in a hospital setting, can support the identification of gait and balance disorders and the implementation of interventions to reduce the risk of falling. Future research efforts based on wearable motion sensor technologies equipped with gyroscopes and accelerometers would help assess the risk of falling during activities of daily life in patients’ real home environment.55
Extrapyramidal signs
A mild increase in muscle tone, usually associated with a concomitant decrease of muscle bulk and strength, is reported with ageing. In this regard, it should be noticed that mild extrapyramidal signs such as axial bradykinesia, rigidity, resting tremor, and postural instability are common amongst community‐dwelling older individuals even if they do not configure a definite PD.56 To achieve the diagnosis of PD, specific criteria have to be satisfied.57 The diagnosis of PD is based on a three‐step process. First, parkinsonism is defined by the presence of bradykinesia (e.g. slowness of movement) in combination with tremor and/or rigidity. If the criteria are not met (step 1), prodromal or non‐clinical parkinsonism could be considered (in addition to other non‐parkinsonian tremulous conditions, such as essential or dystonic tremor). Once parkinsonism is diagnosed, it should be determined whether this condition is attributable to idiopathic PD: when absolute exclusion criteria (e.g. brain lesions, drug‐induced parkinsonism, etc.) (step 2) are absent and supportive clinical features (e.g. olfactory loss, sleep disturbances, and other non‐motor symptoms) are present (step 3).58 Hence, the presence of isolated tremor, rigidity, or simple slowness of movement is not sufficient to configure the diagnosis of PD per se. More importantly, senile tremor constitutes one of the commonest movement disorders, reaching a prevalence of ~10% in subjects by age 90.59 This so‐called ageing‐related tremor emerges in midlife and increases with ageing. The exact nature of this tremor remains unclear, configuring a wide spectrum of disorders that encompasses essential tremor (e.g. idiopathic), dystonic tremor (e.g. tremor associated with dystonia in any body region), and also PD, being associated both with increasing cognitive impairment and mortality.58
Cognitive changes with ageing
Declines in an individual’s cognitive functioning are generally considered unavoidable with ageing. Nevertheless, age‐related cognition changes are not uniform, and extreme heterogeneity in cognitive performance is observed among older people. In fact, some older adults retain excellent cognitive performance, sometimes outperforming younger subjects. Others, although within the range of normalcy, show early signs of decline.60 Such inter‐individual variability is likely attributable to a wide range of factors, including biological, psychological, health‐related, environmental, and lifestyle determinants, and is probably related to varying activation of compensatory mechanisms.60 Multiple sociodemographic variables such as education and lifestyle parameters, including physical and social activity and dietary/nutritional habits, can influence cognition.61,62 Various chronic conditions such as diabetes, hypertension, vascular disorders, and depression can contribute to cognitive decline, and their prevention and management are essential to cognitively healthy ageing.63,64 Accordingly, diabetes, midlife hypertension, midlife obesity, physical inactivity, depression, smoking, and low educational attainment have emerged as the main modifiable risk factors for dementia, accounting for around one‐third of AD and vascular dementia cases worldwide.65,66 There is also recent evidence that performance on neuropsychological tests can be affected by the individual’s frailty status, which is a composite of health and biological deficits accumulated by the organism.67 Based on this premise, a proper assessment of cognitive functioning in older people requires approaches and
