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Nathan Herrmann

Publications and source records attributed to Nathan Herrmann.

At least 19 recordsLinked to original sources
PubMed2025

Multiscale dispersion entropy of resting-state EEG in older adults with Alzheimer's disease, mild cognitive impairment, and remitted major depressive disorder.

BackgroundMultiscale dispersion entropy (MDEnt) is a nonlinear EEG measure that quantifies brain complexity across time scales, reflecting both local and global brain dynamics. Previous research indicates lower complexity at short time scales in Alzheimer's disease (AD) compared to mild cognitive impairment (MCI) and healthy controls (HCs), with MCI also showing lower values than HCs. Major depressive disorder (MDD) has also been preliminarily linked to reduced complexity during acute episodes.ObjectiveTo assess whether MDEnt at short time scales can distinguish AD from MCI and HCs, and to examine complexity differences across additional groups, remitted MDD (rMDD) and rMDD + MCI, while exploring associations with cognitive performance.MethodsThe study included 316 older adults: 44 HCs, 46 with rMDD, 114 with MCI, 71 with rMDD + MCI, and 41 with AD. Resting-state, eyes-closed EEGs were analyzed using MDEnt at 24 ms (short) and 60 ms (long) time scales. Cognitive function was measured with the Montreal Cognitive Assessment and a composite cognitive score.ResultsShort time scale complexity was lowest in AD, followed by MCI, and highest in HCs; rMDD presence had no impact. Only AD showed reduced complexity at long time scales. Complexity at both time scales was significantly correlated with cognitive performance.ConclusionsThis study highlights the value of MDEnt to assess complexity at short time scale and differentiate individuals with AD, MCI, or HCs. Reduced complexity in these individuals may underlie their cognitive impairment. In contrast, our study suggests that any MDD impact on complexity is likely related to active depressive symptoms.

Humans↗
PubMed2007

Epidemiology of social phobia in later life.

OBJECTIVE: Although anxiety disorders, including social phobia (SP), are common among older adults, very little is known about the epidemiology of SP in later life. METHOD: Using data drawn from a large, nationally representative sample of older adults from Canada (N=12,792), the authors estimate lifetime and 12-month prevalence of social phobia and examine demographic predictors and patterns of comorbidity of current SP in this population. RESULTS: The results reveal that SP is a prevalent disorder in later life with lifetime and 12-month prevalence estimates of 4.94% and 1.32%, respectively. Current SP (12-month) declines with age and is more common in individuals with other psychiatric disorders. Interestingly, there is no correlation between current SP and gender, marital status, or socioeconomic status. CONCLUSIONS: SP remains a highly prevalent disorder even in late life with the pattern of feared/avoided situations being strikingly similar to that of younger populations.

Age Distribution↗
PubMed2006

A placebo-controlled trial of valproate for agitation and aggression in Alzheimer's disease.

BACKGROUND/AIMS: To assess the efficacy and tolerability of valproate for the treatment of agitation and aggression in moderate-to-severe Alzheimer's disease (AD). METHODS: This was a randomized, double-blind, placebo-controlled crossover trial of valproate in institutionalized AD patients. Patients were assessed with the Neuropsychiatric Inventory (NPI) and Cohen-Mansfield Agitation Inventory at baseline and after 6 weeks of treatment with valproate and placebo, with 2 weeks between phases to allow for placebo washout and tapering. RESULTS: Fourteen patients (8 male/6 female) aged 85.6 +/- 4.5 years with baseline Mini Mental State Examination scores of 4.5 +/- 4.6 and NPI agitation/aggression scores of 6.4 +/- 3.5 were randomized to treatment. NPI agitation/aggression treatment change scores significantly worsened during valproate treatment compared with placebo (Z = -2.03, p = 0.04). Tolerability of valproate was also poor, with patients experiencing a significantly greater mean number of adverse events during valproate therapy compared to placebo (Z = -2.82, p = 0.005). CONCLUSION: Valproate is not effective for the management of agitation in moderate-to-severe AD, and may be poorly tolerated in this population.

Aged↗
PubMed2006

Predictors of driving cessation in mild-to-moderate dementia.

BACKGROUND: Although physicians in most provinces are mandated to report patients whose driving ability is impaired by illness, little is known about dementia-related factors associated with driving cessation. The purpose of our study was to explore factors that may affect the likelihood of driving cessation in a sample of elderly, community-dwelling patients with dementia. METHODS: A 3-year prospective study, the Canadian Outcomes Study in Dementia (COSID) has enrolled 883 patients with mild-to-moderate dementia at 32 centres across Canada. Assessment tools included the Mini-Mental State Examination (MMSE) for cognition, the Global Deterioration Scale (GDS) for staging (severity), the Functional Autonomy Measurement System (SMAF) for function, and the Neuropsychiatric Inventory (NPI) for behaviour. Factors associated with the decision to quit driving after the baseline assessment were tested with Cox survival analysis. RESULTS: Of 719 subjects who were or had been drivers, 203 (28.2%) were still driving at baseline. Over an observation period that averaged 23 months, 97 (48.5%) of 200 patients quit driving. Factors predictive of driving cessation included GDS (hazard ratio [HR] 1.68, 95% confidence interval [CI] 1.15-2.45), MMSE score (HR 0.90, 95% CI 0.83-0.97) and NPI findings (HR 1.63 for presence of > or = 3 behaviours, 95% CI 1.01-2.62). Among the NPI behaviours, when they were analyzed separately, agitation led to a decreased likelihood of driving cessation (p = 0.019), whereas apathy (p = 0.031) and hallucinations (p = 0.050) led to an increased likelihood. INTERPRETATION: Cognitive impairment and behaviours such as agitation, apathy and hallucinations were significant predictors of driving cessation in patients with a mild to moderate degree of dementia. These findings should be considered when one counsels patients and their families.

Accidents, Traffic↗
PubMed2006

Behavioral correlates of GABAergic disruption in Alzheimer's disease.

BACKGROUND: Losses of gamma-aminobutyric acid (GABA) have been variably demonstrated in Alzheimer's disease (AD) and may be related to the presence of behavioral and psychological symptoms of dementia (BPSD) in AD. Our objective was to assess the relationship between plasma GABA (pGABA) levels and specific BPSD in patients with severe AD. METHODS: pGABA levels and BPSD were measured in 14 institutionalized AD patients (8M/6F, mean age +/- S.D. = 85.6 +/- 4.5 years) with severe cognitive impairment (Mini-mental State Examination score = 4.5 +/- 4.6) and prominent behavioral disturbances (Neuropsychiatric Inventory (NPI) score = 33.4 +/- 23.6). RESULTS: pGABA was positively correlated with depression and apathy scores on the NPI and negatively correlated with age. Apathy and age were independent predictors of pGABA levels. CONCLUSIONS: The final stages of AD are associated with GABAergic changes, which may contribute to depression and apathy in AD.

Affect↗
PubMed2006

IPA survey of brief cognitive screening instruments.

BACKGROUND AND OBJECTIVES: Cognitive screening is a "first step" in detecting dementia and other neuropsychiatric syndromes and hence represents an important public health and clinical initiative. A plethora of cognitive screening instruments has been advocated in recent years, but the extent to which these instruments are used or their effectiveness is not well known. An International Psychogeriatric Association (IPA) survey was designed to determine which cognitive screening instruments were used most frequently by clinicians with special expertise in the neuropsychiatric aspects of old age and also to determine the ones considered most useful by these specialists. METHOD: Under the auspices of the IPA, the survey was mailed in the fall of 2004 to all IPA members as well as members of the American and Canadian Associations of Geriatric Psychiatry. The survey inquired about demographic information, the frequency of use of cognitive screening instruments, and the value attributed to the cognitive screening instruments. Participants also had an opportunity to provide written commentary. RESULTS: A total of 334 completed surveys were processed. The majority of respondents were geriatric psychiatrists (58%). Of the 20 different instruments that were listed on the survey, only six were selected as "routinely" or "often used" by the survey respondents. These instruments in declining order were: (1) the Folstein Mini-mental State Examination; (2) the Clock Drawing Test; (3) Delayed Word Recall; (4) the Verbal Fluency Test; (5) Similarities; and (6) the Trail Making Test. "Effectiveness" and "ease of administration" were the test characteristics most highly predictive of frequency of use. Open-ended comments highlighted patient factors that continue to provide challenges, including ethnicity/culture, language, education/literacy, and sensory impairment. Respondents concluded that "no single test is adequate." CONCLUSIONS: Psychogeriatricians worldwide routinely use a relatively small number of brief cognitive screening instruments. Further evaluation is necessary as the need increases for cognitive screening guidelines that inform public health initiatives related to dementia and neuropsychiatric syndromes.

Adult↗
PubMed2006

Effect of antidepressant use on admissions to hospital among elderly bipolar patients.

OBJECTIVE: The goal of this study was to examine the association between antidepressant use and hospitalization rate for mania or bipolar depression in a large, community-based sample of elderly bipolar patients. METHOD: Population-based retrospective cohort design. Administrative healthcare databases were linked for all individuals aged 66 years or older in the Province of Ontario, Canada. Bipolar subjects who received a prescription for an antidepressant medication (n = 1,072) between 1 April 1997 and 31 March 2001 comprised the antidepressant cohort. The control group (n = 3,000) consisted of randomly selected subjects from the eligible bipolar population who did not receive a prescription for an antidepressant medication during the same surveillance period. Primary outcomes were admission to hospital for a manic/mixed or depressive episode. RESULTS: During a total of 5135 person-years of follow up, 113 admissions for a manic/mixed episode and 28 admissions for a depressive episode were identified. Model based estimates adjusted for a number of covariates revealed that, as compared with the control group, the antidepressant cohort had significantly lower likelihood of admissions for manic/mixed (adjusted rate ratio [aRR] = 0.5, 95% CI = 0.3-0.8) but not depressive episodes (aRR = 0.7, 95% CI = 0.2-2.2). CONCLUSION: Antidepressant use among elderly bipolar patients was associated with decreased rates of hospitalization for manic/mixed episodes. This finding requires confirmation with further data of antidepressant use among elderly bipolars.

Aged↗
PubMed2006

The contribution of neuropsychiatric symptoms to the cost of dementia care.

OBJECTIVE: To estimate the contribution of behavioral and psychological symptoms of dementia (BPSD) to the costs of care. METHOD: A one-year prospective study of resource utilization recorded monthly by 500 caregivers of community dwelling patients with dementia. The effect of behavior on total, direct and indirect costs of care was examined. RESULTS: The total cost of care was $1,298 per month and there was a significant independent relationship between costs and BPSD. The incremental cost of a one point increase in Neuropsychiatric Inventory score was $30 per month (95% CI: $19-$41). CONCLUSION: BPSD contribute significantly to the overall costs of dementia care. Interventions targeted at BPSD may help to reduce the staggering societal costs of this illness.

Aged↗
PubMed2006

Outcome after traumatic brain injury sustained in older adulthood: a one-year longitudinal study.

OBJECTIVE: The objective of this study was to explore the effects of traumatic brain injury (TBI) on cognition and functioning in older adults in a one-year longitudinal study. METHODS: Participants with mild-to-moderate TBI were compared with an age-, gender-, and education-matched healthy comparison group on aspects of cognition. Neuropsychologic tests were administered at one year. Self-reported measures of functioning were completed at baseline, six months, and one year. Informants rated instrumental functioning at one year. RESULTS: Sixty-nine subjects aged 50 years and over (mean: 67 years; standard deviation: 7.9) and a comparison group of 79 participants were assessed. Patients with TBI had poorer processing speed, verbal memory, language, and executive function; they self-reported more psychologic distress, psychosocial dysfunction, and postconcussive symptoms; and they were rated as more impaired in functioning than the comparison group. TBI of moderate severity accounted for most of the between-group differences. CONCLUSION: TBI, particularly of moderate severity, led to poorer cognitive and psychosocial functioning one year postinjury among older adults. The clinical significance of this may become more evident with time in this vulnerable population.

Aged↗
PubMed2006

Prevalence and correlates of agoraphobia in older adults.

OBJECTIVE: Agoraphobia has been previously found to be a relatively prevalent disorder in the older adult. However, little is known about the nature of this disorder in the elderly population. The purpose of this study was to identify risk factors, illness characteristics, and comorbidity of agoraphobia in the elderly. METHODS: This was a national community mental health survey that included 12,792 individuals > or = 55 years. Agoraphobia was assessed using the World Mental Health Composite International Diagnostic Interview. Social, demographic, psychiatric, and physical variables previously found to be associated with agoraphobia in the adult population were measured. Bivariate and logistic regression analyses were used to examine these associations. RESULTS: The prevalence of agoraphobia in adults over 55 was 0.61% (95% confidence interval [CI]: 0.40-0.82). In bivariate analysis, the condition was more common in the younger age groups, women, and those widowed or divorced. It was also more common in individuals with chronic health conditions and those with comorbid psychiatric disorders. However, in the multivariate model, chronic health conditions and panic disorder were no longer significant. Most cases of agoraphobia in the elderly were of early onset (age <55 years). The majority of patients with agoraphobia did not have concurrent panic disorder. CONCLUSION: Lower prevalence rates of agoraphobia in the elderly were found compared with previous studies. The degree to which this is a measurement issue is discussed. The low correlation between agoraphobia and panic disorder raises further questions about the nature and etiology of agoraphobia in the elderly. Implications for future research and clinical practice are discussed.

Adolescent↗
PubMed2006

Comorbidity in bipolar disorder among the elderly: results from an epidemiological community sample.

OBJECTIVE: This study sought to determine psychiatric comorbidity among elderly individuals with bipolar disorder. METHOD: An epidemiological community survey identified 84 elderly (ages >/=65) respondents with bipolar disorder, 1,327 younger adults with bipolar disorder, and 8,121 elderly respondents without bipolar disorder. RESULTS: Elderly respondents with bipolar disorder reported lifetime and 12-month rates of comorbid alcohol use disorders (38.1%, 38.1%, respectively), dysthymia (15.5%, 7.1%), generalized anxiety disorder (20.5%, 9.5%), and panic disorder (19.0%, 11.9%) that were significantly higher than among elderly respondents without bipolar disorder. They had lower lifetime and 12-month rates of alcohol use disorders and lower 12-month rates of dysthymia and panic disorder than younger adults with bipolar disorder. Elderly men with bipolar disorder reported a greater prevalence of alcoholism; women reported a greater prevalence of panic disorder. CONCLUSIONS: Comorbid axis I disorders, including panic disorder, are common among elderly individuals with bipolar disorder.

Adult↗
PubMed2006

Electroconvulsive therapy in older adults: 13-year trends.

OBJECTIVES: To examine temporal trends in electroconvulsive therapy (ECT) use among all 12 million Ontario residents between January 1992 and December 2004 and to examine the differential trends in older adults, compared with younger ones. METHODS: We undertook a time-series analysis to examine annual trends in the use and prevalence of ECT, using linked provincial datasets. Descriptive data were presented for the population as a whole, and then trends were described separately by age groups (younger and older). As a comparator, we similarly examined antidepressant prevalence for older adults over the same time period. RESULTS: Overall rates of ECT prevalence were stable. Annual population rates of individuals receiving ECT increased by about 27%, from 12.3 per 100 000 population in 1992 to 15.6 per 100 000 in 1997, and then decreased to 12.5 per 100 000 by 2004. The population rates of ECT were about threefold higher among older adults, relative to the younger population. Antidepressant prevalence increased by 90.1% among older adults over the same time period. The female-to-male ratio was relatively stable over time. CONCLUSIONS: The rate of ECT has been relatively stable since the early 1990s. Older adults were much more likely to be prescribed a course of ECT than younger adults. ECT remains a commonly prescribed treatment, particularly in old age.

Adult↗
PubMed2006

Atypical antipsychotics for neuropsychiatric symptoms of dementia: malignant or maligned?

Recent concerns regarding the use of atypical antipsychotics when used for the treatment of neuropsychiatric symptoms in dementia have led to a flurry of studies attempting to re-evaluate their place in therapy. We critically review current evidence on the safety profiles of these agents in patients with behavioural and psychological symptoms of dementia (BPSD) and provide recommendations to guide the clinician. Potential risks with this class of medications include extrapyramidal symptoms (EPS), weight gain, diabetes mellitus, cardiac conduction abnormalities (e.g. corrected QT [QTc] interval prolongation), cerebrovascular adverse events and mortality. Compared with placebo, treatment of BPSD with atypical antipsychotics leads to little or no increase in EPS and no significant weight change. Compared with typical antipsychotics, treatment of BPSD with atypical antipsychotics leads to a reduced risk of EPS, lower incidences of tardive dyskinesias and no significant weight gain. Atypical antipsychotics have not been associated with glucose intolerance, diabetes or hyperlipidaemia in elderly dementia patients. Both typical and atypical antipsychotics have been associated with cardiac conduction abnormalities, with the magnitude of QTc prolongation being slightly smaller with atypical antipsychotics. Randomised controlled trials suggest that atypical antipsychotics are associated with an increased risk of cerebrovascular adverse events, such as stroke, and an increased mortality compared with placebo. However, it appears that typical antipsychotics have similar risks of cerebrovascular adverse events and death. An increased risk of anticholinergic adverse effects and falls must also be considered with both typical and atypical antipsychotics. In summary, atypical antipsychotics are associated with potentially serious adverse events. Before prescribing these medications in elderly dementia patients, baseline EPS, ECG abnormalities and concomitant medications should be assessed, and the presence of cardiovascular, cerebrovascular and metabolic risk factors should be taken into consideration when benefits and risks are being weighed.

Antipsychotic Agents↗
PubMed2005

Physiotherapy coupled with dextroamphetamine for rehabilitation after hemiparetic stroke: a randomized, double-blind, placebo-controlled trial.

BACKGROUND AND PURPOSE: Hemiparesis is the commonest disabling deficit caused by stroke. In animals, dextroamphetamine (AMPH) paired with training enhances motor recovery, but its clinical efficacy is uncertain. METHODS: In a randomized, double-blind, placebo-controlled trial, 71 stroke patients were stratified by hemiparesis severity and randomly assigned to 10 sessions of physiotherapy coupled with either 10 mg AMPH or placebo. Study treatments were administered by 1 physiotherapist, beginning 5 to 10 days after stroke and continuing twice per week for 5 weeks. Outcomes were assessed by 1 physiotherapist at baseline, after each treatment session, at 6 weeks, and at 3 months. The primary outcome was motor recovery (impairment level) on the Fugl-Meyer (FM) scale. Secondary outcomes assessed mobility, ambulation, arm/hand function, and independence in activities of daily living. RESULTS: Baseline hemiparesis was severe overall (mean FM score 27.7+/-20.0). Motor scores improved during treatment in both groups (mean change, baseline to 3 months 29.5+/-16.6). Repeated-measures ANOVA revealed no significant differences in recovery between the treatment groups for the entire cohort (n=67) or for subgroups with a severe hemiparesis (n=43), moderate hemiparesis (n=24), or cortically based stroke (n=26). In the moderate subgroup, there was a significant drug x time interaction for upper extremity motor recovery (F=5.14; P<0.001), although there was a significant baseline imbalance in motor scores in this subgroup. CONCLUSIONS: In stroke patients with a severe motor deficit, 10 mg AMPH coupled with physiotherapy twice per week for 5 weeks in the early poststroke period provided no additional benefit in motor or functional recovery compared with physiotherapy alone. Patients with moderate severity hemiparesis deserve further investigation. Increased intensity and longer duration drug/therapy dosing regimens should be explored, targeting the upper and lower limbs separately.

Aged↗
PubMed2005

Sedative hypnotics in older people with insomnia: meta-analysis of risks and benefits.

OBJECTIVES: To quantify and compare potential benefits (subjective reports of sleep variables) and risks (adverse events and morning-after psychomotor impairment) of short term treatment with sedative hypnotics in older people with insomnia. DATA SOURCES: Medline, Embase, the Cochrane clinical trials database, PubMed, and PsychLit, 1966 to 2003; bibliographies of published reviews and meta-analyses; manufacturers of newer sedative hypnotics (zaleplon, zolpidem, zopiclone) regarding unpublished studies. SELECTION CRITERIA: Randomised controlled trials of any pharmacological treatment for insomnia for at least five consecutive nights in people aged 60 or over with insomnia and otherwise free of psychiatric or psychological disorders. RESULTS: 24 studies (involving 2417 participants) with extractable data met inclusion and exclusion criteria. Sleep quality improved (effect size 0.14, P < 0.05), total sleep time increased (mean 25.2 minutes, P < 0.001), and the number of night time awakenings decreased (0.63, P < 0.001) with sedative use compared with placebo. Adverse events were more common with sedatives than with placebo: adverse cognitive events were 4.78 times more common (95% confidence interval 1.47 to 15.47, P < 0.01); adverse psychomotor events were 2.61 times more common (1.12 to 6.09, P > 0.05), and reports of daytime fatigue were 3.82 times more common (1.88 to 7.80, P < 0.001) in people using any sedative compared with placebo. CONCLUSIONS: Improvements in sleep with sedative use are statistically significant, but the magnitude of effect is small. The increased risk of adverse events is statistically significant and potentially clinically relevant in older people at risk of falls and cognitive impairment. In people over 60, the benefits of these drugs may not justify the increased risk, particularly if the patient has additional risk factors for cognitive or psychomotor adverse events.

Cognition Disorders↗
PubMed2005

The role of buspirone for the treatment of cerebellar ataxia in an older individual.

BACKGROUND: Buspirone, a 5HT-agonist and D2-dopamine antagonist/agonist, has modest beneficial effects in younger individuals with cerebellar ataxia. However, it is unclear whether it is beneficial and tolerable in older ataxic individuals. OBJECTIVE: To determine if an older individual with cerebellar ataxia would benefit from and tolerate buspirone. METHODS: We performed a single-subject, double-blinded, placebo-controlled randomized-phase study. The 80 year-old subject was to undergo six 4-week testing periods, divided randomly into three treatment and three placebo arms with a 2-week washout period between each arm. Treatment consisted of buspirone hydrochloride. Outcomes were clinical gait and balance testing, posturography testing, and subjective measurement of balance confidence. RESULTS: There were no statistically significant objective improvements with buspirone. The subject experienced a subjective improvement in balance confidence and tolerated treatment. CONCLUSIONS: Single-subject studies can help when it is unclear whether drug trial results with young subjects are generalizable to an older subject. This single-subject study determined that buspirone was tolerable but not clearly beneficial for an ataxic older individual.

Aged, 80 and over↗
PubMed2005

Mild cognitive impairment: an operational definition and its conversion rate to Alzheimer's disease.

OBJECTIVE: Because of discrepant findings regarding the accuracy of mild cognitive impairment (MCI) in predicting Alzheimer's disease (AD), further study of this construct and conversion rates is essential before use in clinical settings. We aimed to develop an operational definition of MCI consistent with criteria proposed by the Mayo Alzheimer's Disease Center, and to examine its conversion rate to AD. METHODS: Patients were identified from an inception cohort of patients with at least a 3-month history of memory problems, and referred to a 2-year university teaching hospital investigation by primary care physicians. We classified 161 nondemented patients at baseline using MCI criteria. Diagnostic workups were completed annually, and patients were classified as meeting criteria for AD or showing no evidence of dementia after 1 and 2 years. RESULTS: Of 161 patients, 35% met MCI criteria at baseline. Conversion rates to AD were 41% after 1 year, and 64% after 2 years. Logistic regression analyses to examine predictive accuracy of MCI after 1 and 2 years, with age and education as covariates, were significant (p < 0.0001). After 1 year, MCI showed an optimal sensitivity of 91% and specificity of 79%, and after 2 years, these values were 88 and 83%, respectively. CONCLUSIONS: MCI is an accurate predictor of AD over 1 and 2 years in patients referred by their primary care physicians. Discrepancies in conversion rates may be due to the manner in which patients are recruited to studies as well as the use of different measures to operationalize the construct.

Aged↗