Clinical significance of primitive reflexes in Alzheimer's disease

Primitive reflexes and dementia in older adults: a meta-analysis of observational and cohort studies

Primitive reflexes (PRs) are clinical signs that indicate diffuse cerebral dysfunction and frontal lesions. We aimed to present a comprehensive analysis of the prevalence and risk of PRs in patients with dementia. English-language articles published from January 1990 to April 2021 were searched in PubMed, ScienceDirect, Cochrane, and Web of Science with keywords. The titles and abstracts of the identified articles were screened to identify potentially relevant papers. Odds ratios and risk ratios were extracted with 95% confidence intervals and combined using the random-effects model after logarithmic transformation. The prevalence in dementia patients was also combined using the random-effects model. This meta-analysis involved 29 studies. The snout reflex (48% of cases) was the most prevalent. It was found that the risk of PRs in individuals with dementia was significantly elevated, ranging from 13.94 to 16.38 times higher than in healthy controls. The grasp reflex exhibited the highest risk for dementia. This meta-analysis showed that the prevalence and the risk of PRs is high in older patients with dementia. Therefore, PRs, especially the grasp reflex, should be carefully assessed as a part of routine physical examination in the diagnostic process for dementia.

The grasp reflex in patients with idiopathic normal pressure hydrocephalus

OBJECTIVE

To investigate the prevalence and intensity of grasp reflexes and to examine changes in these reflexes after shunt surgery in patients with idiopathic normal pressure hydrocephalus (iNPH).

METHODS

We enrolled 147 patients with probable iNPH. A standard procedure was used to determine the presence of grasp reflexes, and the intensity of these reflexes was assessed using a four-category classification. Clinical rating scales and their correlation with grasp reflexes were also evaluated. Grasp reflexes were reassessed in 72 patients 1 year after surgery.

RESULTS

We found that approximately 50.3% of patients with iNPH exhibited a positive grasp reflex. Among these patients, 69% exhibited bilateral positivity, while the remaining patients showed unilateral positivity. Furthermore, the intensity of the grasp reflex was significantly correlated with the severity of gait and with cognitive, urinary, motor, and behavioural symptoms. Surgical interventions led to a reduction (41.7%) or maintenance (30.6%) of the reflex intensity in 72.3% of iNPH patients. The changes in reflex intensity showed significant positive correlations with changes in the number of steps of the Timed Up and Go test and Trail Making Test-A scores but not with changes in total scores on the iNPH Grading Scale.

CONCLUSION

This retrospective study identified grasp reflexes as a highly prevalent phenomenon in patients with iNPH. These reflexes can assist in evaluating the severity of various symptoms, including cognitive, gait, urinary, motor and emotional symptoms.

Spatial-Temporal Parameters of Gait Associated With Alzheimer Disease: A Longitudinal Analysis

Alzheimer's disease (AD) is one of the biggest social and medical concerns in the aging world. A dual task of walking and talking is a particularly practical means to assess AD considering the cognitive and behavioral changes that characterize the disease. The purpose of the study was to assess the effect of the dual task of walking and talking on people with early stage AD under differing cognitive load levels of talking. Participants (9 women and 5 men, mean age (years) = 78.03, standard deviation [SD] = 12.06) with mild or moderate AD (mean Dementia Rating Scale 2 score = 88.14, SD = 7.07) completed 12 monthly walking sessions under no, low, or high cognitive load. They also completed the low and high cognitive load tasks while seated. Linear mixed-effects modeling revealed that values in the Functional Ambulation Profile, stride length, and velocity decreased as tasks became more complex and double support time increased at the same rate. The walking and seated conditions comparison indicated that participants' performance on both low and high cognitive tasks was poor when they were walking rather than seated. The results show that people with early stage AD exhibited gait impairments that increased over time and when completing tasks with greater cognitive load.

[Cortical Release Signs in Patients with Schizophrenia, Depressive Disorders, and Bipolar Affective Disorder]

BACKGROUND AND OBJECTIVES

Determining the presence of cortical release signs associated with white matter damage, is a clinically easy method to perform. The objective of this study is to determine the presence of cortical release signs in patients with mental illnesses and cerebrovascular disease, as well as its clinical usefulness, given that it indicates cortical damage.

MATERIAL AND METHODS

A review was made of cortical release signs in patients hospitalized in clinical psychiatry and general hospitals with bipolar affective disorder (40), depression (37), schizophrenia (33), cardiovascular disease (33) and dementia (37).

RESULTS

The signs of cortical release do not have the same importance as cortical damage. For example, the glabellar reflex was found in all the groups, that of paratonia, particularly in the group with schizophrenia, and others signs in the group of patients with dementia.

CONCLUSIONS

It is suggested that these signs imply subcortical white matter damage. The appearance of these signs shows the need for a follow up of patients diagnosed with bipolar affective disorder, depression and schizophrenia.

Acamprosate and primitive reflexes

OBJECTIVE

To describe 3 cases of patients with alcohol dependence whose primitive reflexes resolved upon initiation of acamprosate 666 mg 3 times daily.

CASE SUMMARIES

A 57-year-old man had a long-standing history of alcohol dependence and a prominent snout reflex. The snout reflex resolved within 24 hours of starting treatment with acamprosate. A 45-year-old man with a long history of alcohol dependence had both a snout and a grasp reflex. These reflexes were present throughout 3 admissions for alcohol detoxification and continued until the end of his third admission, when he elected to begin treatment with acamprosate. Within 24 hours of starting treatment, the snout and grasp reflexes were absent. A 55-year-old man who drank heavily for 35 years presented with both a snout and a grasp reflex on admission. These persisted throughout his detoxification until the day after he had begun treatment with acamprosate. His primitive reflexes remained resolved through the next 4 days until discharge. All 3 of these patients remained on acamprosate at discharge.

DISCUSSION

Alcohol dependence is a common, debilitating disorder. One of the difficulties in treating alcohol dependence is its adverse effect on the brain, as higher aspects of cortical function necessary to maintain abstinence are eroded by alcohol. Acamprosate is a drug intended to help prevent relapse among patients with alcohol dependence. Unexpectedly, acamprosate may resolve primitive reflexes--a neurologic finding that suggests cognitive impairment--among patients with alcohol dependence.

CONCLUSIONS

Acamprosate may relieve snout and grasp reflexes among patients with alcohol dependence.

Prevalence of primitive reflexes and the relationship with cognitive change in healthy adults

OBJECTIVES

Primitive reflexes (PR) generally disappear early in life but may reappear later, in which case they are often associated with chronic neurological conditions, such as dementia or Parkinson's disease. Studies have shown that the presence of PRs may be indicative of both the severity and rate of progression of these diseases and may be the result of disinhibition of cortical networks. The association between PRs and cognitive function in usual ageing is unclear. We investigated whether the occurrence, amplitude, and persistence of four nociceptive (glabbelar tap, palmomental, pollicomental, and snout reflexes), three prehensile reflexes (suck, palmar grasp, and rooting), and two other reflexes (mouth open finger-spread and nuchocephalic reflexes) were related to performance in specific cognitive domains in normal ageing individuals.

METHODS

Four-hundred and seventy normal aging participants (25-82 years) in the Maastricht Aging Study (MAAS), were included in the study. They were neurologically and cognitively screened at baseline and were retested after 3 (only individuals aged 50 years and older at baseline) and 6 years.

RESULTS

The prevalence of most PRs increased with age: 47% of men aged 25-45 years had at least one PR, compared with 73% of men aged 65-85 year (p = 0.002). In women these percentages were 51 and 75, respectively (p=0.008). The prevalence, amplitude, and persistence of PRs were unrelated to cognition at baseline or at the 3- or 6-year follow-up.

CONCLUSIONS

The prevalence of particularly nociceptive reflexes rises substantially with increasing age in normal individuals. However, the presence of PRs cannot be considered to be a marker of cognitive decline in normal aging individuals.

Cortical release signs in psychiatry

OBJECTIVE

To review the role of cortical release signs (CRS) in neuropsychiatry.

METHOD

A thorough literature review was conducted using Medline and Psychlit databases, and other relevant references available to the authors.

RESULTS

A number of neurological abnormalities are reported at elevated rates in neuropsychiatric conditions. CRS are a group of primitive reflexes that are present in the neonate but become inhibited as the infant central nervous system (CNS) develops, only to later re-emerge in the context of CNS disease. The clinical elicitation and interpretation of each CRS is described with reference to its neurobiology. The prevalence of CRS in schizophrenia, affective disorder, obsessive-compulsive disorder, Alzheimer's disease, vascular dementia, frontotemporal dementia and other neuropsychiatric illness allows for their use in the clinical management of these patients, including diagnostic assessment, treatment monitoring and prognosis.

CONCLUSIONS

A number of issues complicate their interpretation in neuropsychiatric illness, including the apparent high base rate of some CRS in non-clinical populations, their increasing prevalence with age, lack of specificity and uncertainty over what constitutes an 'abnormal' response. In some circumstances, CRS may assist in diagnostic differentiation and illness staging.

[Dementia and falls]

INTRODUCTION

Dementia is now a frequent disease in elderly and may be a major risk of falling. Usually these falls are multiple and serious, but their consequences are not specific. All types of dementia (Alzheimer's disease, dementia with Lewy bodies, dementia in Parkinson's disease, fronto-temporal dementia, vascular dementiaellipsis) and all stages of evolution are concerned.

DISCUSSION

These falls result from cognitive and behavioural disorders, visual and motor problems, gait and balance disturbances, malnutrition, adverse effects of medication and fear of falling.

CONCLUSION

Prevention is possible. Attention must be given on the patient himself (keeping in good health, limitation in sedative treatment and mechanical restraintsellipsis) and on his environment (lighting, obstacles on the ground, stress levelellipsis). After a fall, especially after a complicated fall, rehabilitation modalities and aims must be adapted but caring must not be defeatist. Randomized studies need to be realized.

Cognitive ability and functional status

Significant confusion exists in the literature about functional status. Despite its importance, little attention has focused on developing and substantiating frameworks that detail the underpinnings of functional status, which has resulted in lack of agreement about its definition and dimensions. The purpose of this literature review was to examine the development of functional status and to describe the inclusion of its cognitive dimension. Cognition is one key dimension of functional status. One must 'know how' to perform to be successful in an activity. While cognitive capacity is generally considered in relation to functional status, the nature of the cognitive dimension is poorly described and poorly understood. Three databases were selected for review: Citations in Nursing and Allied Health (CINAHL), Psychology Literature (PsychLit), and the Medical data base known as MedLine. Key word searches identified thousands of sources. This analysis includes an extensive sampling of these sources from the 1960s through to 1998. The sources sorted into four primary categories and demonstrate a growing recognition of the cognitive dimension of functional status in the literature. Despite this recognition, the lack of conceptual clarity of both the term functional status and its cognitive dimension limits communication among disciplines and limits comparisons of functional status outcomes across studies. Functional status models are needed that include cognition as a core dimension. Population specific descriptions of the cognitive dimension should be guided by knowledge in the neurosciences.

Characteristics of postural control and locomotion of patients with vascular and Alzheimer-type dementias

The postural control and locomotion of patients with Alzheimer-type senile dementia (n = 20) or vascular dementia (n = 20) were investigated. Patients with both types of senile dementia, especially patients with vascular dementia, generally showed lower scores than healthy old people (n = 53). Moreover, deterioration of locomotion was more remarkable.

Primitive reflexes in Alzheimer's disease and vascular dementia

Data on the prevalence and clinical value of primitive reflexes (PRs) in dementia are controversial, mainly due to a lack of standardization of the methods by which these signs are elicited and scored. A standardized protocol was used to investigate eight PRs in 20 patients with Alzheimer's disease (AD), 20 patients with vascular dementia (VD), and 20 control subjects for each group. Both patient groups showed considerably more PRs than the control groups. The prevalence of PRs was related to the severity of dementia. No single reflex or combination of PR pathognomonic for dementia could be distinguished. The PR profile of AD and VD patients were similar.

Blinking and the release reflexes: are they clinically useful?

OBJECTIVE

To review the clinical utility of blinking and the release reflexes, palmomental, glabellar, grasp, and snout, as an important part of the bedside neurological examination.

DESIGN

Articles published from 1966 to 1993 that addressed blinking or the release reflexes were identified by searching the MEDLINE database. Thirty-seven references provided clinically useful and applicable information.

RESULTS

There is controversy regarding the optimal method of clinical elicitation of these reflexes. The release reflexes are frequently seen as an incidental abnormality in the elderly. A positive grasp reflex, especially if asymmetrical, is sensitive but not specific for abnormal brain function. Lack of habituation is more important than the mere presence or absence of a reflex. The brainstem circuits involved in the regulation of blinking and the release reflexes are discussed, as are their abnormalities in a variety of clinical settings.

CONCLUSION

Blinking and the release reflexes have clinical utility in the diagnosis and bedside clinical assessment of diseases as diverse as frontal lobe lesions, hydrocephalus, multiple sclerosis, Parkinson's disease, Alzheimer's disease and other dementias, falls in the elderly, ageing, HIV-encephalopathy, schizophrenia, tumors in the region of the sylvian aqueduct and recovery from head trauma.