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Tolerance for light and sound of patients with persistent post-concussional symptoms 6 months after mild head injury



Patients with post-concussional symptoms (PCS) about 6 months after a mild head injury (MHI) were examined for tolerance of light and sound in comparison with concussed patients without PCS and non-concussed healthy controls. MHI patients with PCS were individually matched with subjects from the two control groups for the time elapsed from the injury, and for age and sex. Using a computerized rating technique, we assessed both the maximal and submaximal levels of lowered tolerance for light and sound over a wide range of stimuli. We found that the MHI patients with PCS 6 months after the trauma (n = 11) tolerated significantly less well stimuli of intensities of 71 dB and 500 lx than MHI patients without PCS (n = 11) and non-concussed controls (n = 11). There were no significant differences in tolerance for light and sound between MHI patients without PCS and the non-injured controls. Decreased tolerance for light and sound may contribute to the persistence of symptoms up to 6 months after a mild head injury. The psychophysical method provides an objective measure for the evaluation of the late persistent post-concussional syndrome.
J Neurol (1991) 238 : 443-446
© Springer-Verlag 1991
Tolerance for light and sound of patients
with persistent post-concussional symptoms
6 months after mild head injury
N. Bohnen 1, A. Twijnstra 2, G. Wijnen 1 , and J. Jolles 1
1Department of Neuropsychology and Psychobiology, University of Limburg, P.O. Box 616, NL-6200 MD Maastricht, The Netherlands
2Department of Neurology, University Hospital, Maastricht, The Netherlands
Received November 20, 1990 / Received in revised form April 4, 1991 / Accepted April 9, 1991
Patients with post-concussional symptoms
(PCS) about 6 months after a mild head injury (MHI)
were examined for tolerance of light and sound in com-
parison with concussed patients without PCS and non-
concussed healthy controls. MHI patients with PCS were
individually matched with subjects from the two control
groups for the time elapsed from the injury, and for age
and sex. Using a computerized rating technique, we as-
sessed both the maximal and submaximal levels of low-
ered tolerance for light and sound over a wide range of
stimuli. We found that the MHI patients with PCS 6
months after the trauma (n = 11) tolerated significantly
less well stimuli of intensities of 71dB and 5001x than
MHI patients without PCS (n = 11) and non-concussed
controls (n = 11). There were no significant differences
in tolerance for light and sound between MHI patients
without PCS and the non-injured controls. Decreased
tolerance for light and sound may contribute to the per-
sistence of symptoms up to 6 months after a mild head
injury. The psychophysical method provides an objective
measure for the evaluation of the late persistent post-
concussional syndrome.
Key words:
Light - Sound - Tolerance - Post-concus-
sional syndrome
Post-concussional symptoms (PCS) occur in many pa-
tients with mild head injury (MHI) [10, 11], and include
headache, dizziness, easy fatigability, insomnia, lowered
tolerance for noise and light, irritability and difficulty
with memory and concentration. Although patients may
recover completely within some weeks, there is a fairly
high proportion of patients who report symptoms after
the first weeks of recovery [13]. Because there is often
litigation when personal injuries are involved, especially
when the complaints persist, the validity of patient's per-
Offprint requests to: N. Bohnen
sistent PCS comes under question. Both organic and
psychological factors have been considered to explain
the occurrence of persistent PCS [10]. Neuropsychologi-
cal investigations to assess cognitive deficits after MHI
have indicated that subtle impairments in the rate of in-
formation processing and in reaction time are initially
present but may disappear within a couple of months [1,
9, 10]. Although repeated neuropsychological testing
has, up to now, not allowed a straightforward interpreta-
tion of whether or nor significant cognitive disability is
present, evidence indicates that a fairly high proportion
of MHI patients (over 20-50%) still complain of behav-
ioural dysfunction up to 3-6 months after injury [1, 9,
12]. The fact that a clear-cut organic or neuropsycholog-
ical dysfunction cannot be found leads to a more psycho-
genic interpretation of the persistent subjective symp-
toms [5, 12].
The objective testing of tolerance for light and sound
has been proposed as a procedure to obtain evidence of
an underlying organic dysfunction. Waddell and Gronwall
[16] demonstrated that MHI patients had a significantly
lower threshold tolerance for light and a slightly decreased
tolerance for sound 1-3 weeks after injury than healthy
controls. In addition, Jonsson et al. [8] found that MHI
patients with persistent symptoms on average 3 months
after the trauma had a decreased tolerance for light and
sound in comparison with both neurotic patients and
normal control subjects.
Unfortunately, there have been no psychophysical
studies that have objectively assessed the tolerance for
light and sound of MHI patients at later post-injury times
or compared MHI patients with and without PCS. The
aim of the present study was therefore, to compare the
maximal and submaximal levels of reduced tolerance for
light and sound stimuli of MHI patients with PCS with
those of matched patients without PCS and healthy non-
concussed controls. We also investigated whether pa-
tients without PCS had a different tolerance for light and
sound from non-concussed controls.
We used an objective method of assessing tolerance
for light and sound that not only measures the maximal
level of lowered tolerance, but that can also be used to
compare the submaximal levels of lowered tolerance by
applying a graded tolerance scale for each stimulus. Re-
cently, we found that MHI patients 3-6 days after injury
tolerated intense light and sound stimuli both at maximal
and at submaximal levels of reduced tolerance less well
than controls.
Non-uniform criteria for defining MHI have undoub-
tedly contributed to conflicting findings obtained in stud-
ies on the post-concussional syndrome. Clearly defined
eligibility criteria were applied in the present study, i.e.
patients with an uncomplicated MHI, a post-traumatic
amnesia of less than 60 min, a loss of conciousness of less
than 15 min and a Glasglow Coma Score of 15 on admis-
sion and the absence of a focal neurological deficit.
Subjects and methods
Patients were selected for post-concussional behavioural dysfunc-
tion from a larger group of patients who had participated in a com-
prehensive study of MHI patients. The criteria for inclusion in the
study included an elapsed time after the injury of about 6 months,
a period of unconsciousness ranging from some several seconds to
15 min, post-traumatic amnesia for less than 60 min, and an EMV
(Glasgow Coma) score on admission of 15. None of the patients
had evidence of a focal neurological deficit, or of a skull fracture.
Patients were excluded if they had consumed alcohol at the time of
the accident or if they had a history of pre-existing emotional prob-
lems. In addition, patients with hearing and visual problems were
not eligible. Eleven patients with persistent PCS were selected and
individually matched with both a patient without PCS and a non-
concussed control subject for sex, age (SD 5 years) and time
elapsed after injury (SD i-2 months). Normally, younger males
are over-represented in a head-injured population. The applica-
tion of strict eligibility criteria, especially the exclusion of intoxi-
cated subjects, may have reduced the male-to-female sex ratio in
the present study of patients with an uncomplicated MHI. The
non-concussed control subjects were recruited from a pool of heal-
thy volunteers. Data on sex, age and post-injury time for each
group are presented in Table 1. The study was approved by the
ethical council of the University Hospital and all subjects gave
their informed consent.
Table 1. Sex, age (years) and time (months) elapsed after injury.
Group I, MHI patients with persistent post-concussional symp-
toms: group It, MHI patients without symptoms; group III, non-
concussed healthy subjects
Group I Group II Group Ill
No. Sex Age Time No. Sex Age Time No. Sex Age
1 F
24 6.0
l F 22 5.0 1 F
2 M 34 6.5 2 M 36 6.5 2 M 29
3 M 24 6.0 3 M 24 7.0 3 M 26
4 F 23 6.0 4 F 25 5.0 4 F 22
5 F 47 6.5 5 F 42 8.5 5 F 47
6 F 18 6.0 6 F 18 6.0 6 F 18
7 M 44 6.0 7 M 39 6.0 7 M 43
8 M 27 5.0 8 M 22 6.0 8 M 30
9 F 20 7.0 9 F 16 5.5 9 F 19
10 M 35 6.5 10 M 36 6.0 10 M 38
I1 F 51 7.0 11 F 49 6.5 11 F 54
Mean 31.5 6.2 29.9 6.2 31.6
(SD) 11.4 0.6 10.9 1.0 12.1
Post-concussional symptoms
A checklist of PCS was completed, which included items such as
headache, dizziness and irritability. As these symptoms may also
occur in healthy individuals [5], the symptoms were scored for the
absolute or relatively increased appearance after the injury in com-
parison with the pre-traumatic condition. All patients with PCS
complained of three or more symptoms. The frequency of the re-
ported symptoms in the symptomatic patient group (n = 1 l) was as
follows: headache (n = 7), nausea (n = 1), fatigue (11 = 9), dizzi-
ness (n- 6), forgetfullness (n= 7), problems with concentration
(n = 8), intolerant to light (n = 5), intolerant to noise (n = 7), and
blurred vision (n = 2).
Procedure for rating the magnitude of tolerance
Light and sound stimuli of five different intensities were presented
using an IBM-XT personal computer. The computer contained a
parallel interface and controlled both a tone generator (calibrated
for 1000 Hz) with varying amplitude and a 50 W tungsten-halogen
lamp. The tone generator was connected to a pair of ATH-910 ear-
phones (Audiotechnica) with noise-reducing caps. A 50 W incan-
descent lamp was placed on a round tube. The glass-covered aper-
ture (10cm in diameter) was surronnded by a black ring and the
tube was mounted on a mobile and adjustable stand, so as to adjust
the height to the individual patient. The intensities were calibrated
at 1 m distance of the lamp in a room with a background illumina-
tion of 300 Ix.
Five intensities of sound and light were chosen on the empirical
basis that they could be distinguished clearly by the human ear
and eye (57, 71, 81, 89 and 95 dB for sound and 440,500,600, 1000
and 15001x for light). Each of the five intensities was randomly
presented 8 times; there were separate sessions for the two types of
stimuli. Thus, a subject received a total of 40 sound stimuli and 40
light stimuli. Each stimulus was presented for 4 s and was followed
by a constant interval. The rise-fall time of the physical stimulus
was greater than 10 ms. The interval was kept constant in order to
achieve a relative constancy in individual habituation processes
(for sound 6s and for light 12s; see also [3, 15]). During this inter-
val, the subject was asked to evaluate the preceding stimulus on a
7-point rating scale, ranging from totally tolerant/bearable (score:
sO), via very mildly (sl), mildly (s2), moderately (s3), moderately
to severely (s4), severely (s5), to totally unbearable/reduced toler-
ance (s6). The response was given by pressing a button on a 7-
point keyboard. After the session, the median tolerance value per
subject was calculated for each intensity level. These median val-
ues were used for statistical analysis.
The background levels of noise in the examination room ranged
from 46 to 51 dB. Before putting on the earphones, the subject re-
ceived the following instructions: "You will hear a series of sounds
of varying intensity through your headphones. Each sound will be
presented for 4 s. After the tone has finished, please press the but-
ton on the 7-point keyboard that corresponds to the degree of to-
lerance you have experienced. The left button means that you can
tolerate the sound stimulus; the one of the extreme right means
that you find the sound unbearable. The buttons in-between corre-
spond to a decreasing scale of tolerance from left to right. A new
stimulus will be presented automatically after 6s. Forty stimuli of
mixed intensity will be given at random 2"
The average background illumination in the examination room
was about 3001x. The room had dimmed windows. Each subject
was seated so as to look into the centre of the light source at 1 m
distance from their eyes. The subjects received the following in-
structions: "Look into the centre of the lamp. The lamp will shine
for 4s. You will then have 12s to press a button on the 7-point
keyboard that corresponds to the degree of tolerance you have ex-
perienced. The left button means that you can tolerate the light
stimulus; the one on the extreme right means that you find the
light unbearable. The buttons in-between correspond to a decreas-
ing scale of tolerance from left to right. Each new stimulus will be
presented automatically after 12 s. Forty stimuli of different inten-
sity will be given at random."
Statistical analysis
We first assessed whether there was an overall difference between
the three groups for all the five intensities of light and sound. Be-
cause of the ordinal level of the rating scale, the ranks over all ob-
servations per intensity were calculated [4] and were analysed by
multivariate analysis of variance (SAS) [14]. Then separate analy-
ses per intensity were carried out using Duncan's multiple range
test as a post hoc test to evaluate between-group differences for
significant overall effects. A probability level of less than 0.05 de-
fined a significant difference.
Multivariate analysis of variance yielded a significant
overall effect for tolerance for both sound (Wilk's lamb-
da: F(5.25) = 2.75, P< 0.05) and light (Wilk's lambda:
F(5.25) = 4.10, P<0.001). Post hoc testing indicated
that the MHI patients with PCS tolerated the 71, 81, 89
and 95 dB, and the 500, 600, 1000 and 1500 lx levels sig-
nificantly less well than the patients without PCS and the
non-concussed controls (see also Fig. 1). The patients
without PCS did not have a significantly different toler-
ance from that of the non-injured healthy controls for
any of the intensities, except for a decreased tolerance to
the 600 lx light stimulus.
At an individual level, there were seven MHI patients
with PCS who demonstrated a severely to totally reduced
level of tolerance (tolerance scores of 5-6) to 95 dB com-
pared with one patient without PCS and none of the
non-concussed control subjects. Five patients with PCS
compared with one patient without PCS and none of the
non-concussed control subjects showed severely to to-
tally reduced tolerance to 1500 Ix.
There has been much debate over the years as to whether
minor head injuries result in significant and persistent
cerebral damage, and if present, whether it is demon-
strable by objective methods. Experimental studies and
human autopsy data have shown that even MHIs may
lead to anatomical abnormalities [2]. However, other
patients may recover quickly and be without symptoms
after a MHI. Although it has been reported that persis-
tent behavioural dysfunction after a MHI is not explicitly
associated with cognitive disability [9, 12], Ewing et al.
[6] provided evidence that persisting cognitive effects
may still be present after a MHI, but only emerge under
the effects of stress.
Jonsson et al. [8] found that MHI patients with persis-
tent PCS at an average of 3 months after injury had a sig-
nificantly lower ability to endure intense sound and light
stimuli than control subjects. The present results indi-
cate that tolerance for light and sound is significantly
decreased in MHI patients with persistent symptoms
6 months after injury compared with the tolerance of
matched patients without PCS and non-concussed con-
trols. With respect to sub-maximal levels of tolerance to
less intense stimuli, MHI patients with PCS were signifi-
cantly less tolerant to low sound (71 dB) and light inten-
sities (500 lx) compared with patients from the two con-
trol groups. This means that, for example, the shining of
a lamp or the noise of a lively conversation could disturb
a MHI patient who has persistent symptoms. Although
patients without PCS did not differ significantly from the
healthy control subjects in their tolerance for light and
sound, there was a very slight tendency to a decreased
tolerance for light.
Waddell and Gronwall [16] found in their study that
all MH! patients with decreased tolerance for sound and
light had evidence of reduced functions of information
processing. Additionally, Jonsson et al. [8] reported that
symptomatic patients had a lowered tolerance for light
and sound stimuli after a MHI than had symptomatic
non-concussed neurotic patients. These findings may
provide evidence for the hypothesis that there is an or-
ganic basis for this type of hyperaesthesia. Nevertheless,
further studies are needed to establish this hypothesis.
Tolerance to light Tolerance to sound
[, Patients with PCS
, Patients with PCS
5~-r"l Patients without PCS T
I 5
[] Patients without PeS
Healthy subjects _ / I
g g
2 2
440 500 600 1000 1500 57 71 81 89 95
Lux Decibel
Fig. 1. Mean levels of tolerance of
the patient and control groups per
intensity (means + SEM are
presented). The 7-point rating
scale ranged from totally tolerant/
bearable (score:s0), via very
mildly (sl), mildly (s2), moder-
ately (s3), moderately to severely
(s4), severely (s5), to totally
unbearable/reduced tolerance (s6)
It is possible that the post-traumatic changes in toler-
ance for light and sound are a manifestation of a lack of
inhibitory control by orbital frontal cortex areas over
sensory information processed by posterior brain areas
and subcortical centres [7, 17]. The changes in the visual
and acoustic system following MHI may persist together
with subjective symptoms.
It can be concluded that MHI patients with PCS may
already be disturbed by sound or light intensities com-
mon to daily life up to 6 months after injury, whereas pa-
tients without PCS can normally tolerate more intense
stimuli of sound and light. The present study provides an
objective measure for the assessment of persistent PCS
in uncomplicated MHI patients with no pre-morbid ab-
Acknowledgements. The authors thank Marlies Adriaans and Lies-
beth Bloemers for excellent technical assistance.
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... light sensitivity, photophobiadis a common posttraumatic symptom. 11 Also, while there is still controversy surrounding the nature of posttraumatic headaches, 63,73 such headaches can have migrainous features, including light intolerance. 83 It is reasonable to speculate that reducing the intensity of light with the use of filters may alleviate these symptoms in mTBI. ...
... It would be helpful if future studies of filters concentrated on proving their efficacy for the specific symptom of light sensitivity, which can be measured in mTBI. 11 ...
A number of treatment approaches have been advocated for visual complaints, particularly for persistent symptoms following mild traumatic brain injury (mTBI). These include devices such as binasal occlusion, yoked prisms, vertical prisms, and filters--as well as vestibular training. We discuss the rationale and the evidence for each of these approaches. Binasal occlusion has been advocated for visual motion sensitivity, but it is not clear why this should help, and there is no good evidence for its symptomatic efficacy. Base-in prisms can help manage convergence insufficiency, but there are few data on their efficacy. Midline shift is an unproven concept, and while yoked prisms may have some effect for patients with egocentric neglect, their use in mTBI is more questionable. A wide variety of post-traumatic symptoms have been attributed to vertical heterophoria, but this is an unproven concept, and there are no controlled data on the use of vertical prisms for mTBI symptoms. Filters could plausibly ameliorate light intolerance, but studies are lacking. Better evidence is emerging for the effects of vestibular therapy, with a few randomized controlled trials that include blinded assessments and appropriate statistical analyses. Without more substantial evidence, the use of many of these techniques cannot be recommended and should be regarded as unproven, and in some cases implausible.
... [22] Those with post-concussion syndrome may retain an increased sensitivity to light for a longer time. [23] A large contribution to prolonged post-traumatic photophobia may be related to the comorbidity of migraine-like headache after TBI. [18] Furthermore, patients tend to be particularly sensitive to artificial indoor light and all kinds of electronic screens. ...
Full-text available
Purpose of Review Concussion frequently results in visual symptoms, necessitating careful neuro-ophthalmic examination. Both afferent and efferent visual systems are sensitive to brain injury. The present review focuses on the pathophysiology, clinical presentations, examinations, management, and future directions regarding visual disturbances after concussion. Recent Findings Photophobia is common in both acute and chronic concussion. Abnormalities of accommodation, convergence, saccades, and smooth pursuits can result in blurred vision, double vision, and difficulty with near work. Vision-based testing is crucial in the detection of concussion. Retinal nerve fiber layer thickness measurement may elucidate the risk of structural and functional sequelae. Patients presented with visual field loss or cranial neuropathies require evaluation for structural lesions. Summary Proper neuro-ophthalmic examination is instrumental in clinical decision-making for the diagnosis and management of concussion, as well as directing future investigations on preventing long-term complications.
... To achieve this, the study would need to be replicated and a comparison made with a sample of participants with no mTBI. Previous studies that have adopted this methodology have found that individuals who experience mTBI have greater NS one month after injury when compared to non-injury control groups [72,73]. Hence, in addition to the influence of psychological factors, NS could also be associated with injury related factors such as diffuse axonal injury in the central auditory pathway [74], disruptions in temporal and frontal brain regions associated with auditory processing [75] or due to dysfunctional auditory efferent systems [76]. ...
Background Noise sensitivity (NS) following mild traumatic brain injury (mTBI) is common impacts functioning and outcomes. Recent research suggests psychological factors may have a significant role in the development of NS after mTBI. Psychological interventions have been advocated for to reduce this experience. To be effective, these interventions must aim to target the psychological processes that contribute to this relationship. Fear avoidance holds promise in this regard. The current study aimed to explore the role of fear avoidance in NS and examine its role in mediating the relationship between psychological distress and NS. Method Adults (n = 234) diagnosed with mTBI were recruited from outpatient mTBI clinics throughout New Zealand. Participants completed self-report measures of pre-injury mental health status, as well as current post-concussion symptoms, psychological distress (anxiety, stress, depression, fear avoidance and post-traumatic stress symptoms) and functional status upon entry to an mTBI outpatient clinic (M = 8.9, SD = 9.2, post injury). Results A pre-injury mental health diagnosis was associated with NS after mTBI, as were symptoms of anxiety, stress, depression, and post-traumatic stress. Regression analyses revealed that fear avoidance (β = 0.45, p = .01), as well as stress (β = 0.07, p = .01) and PTSD symptoms (β = 0.02, p = .01), made a significant and unique contribution to NS. A series of mediation analyses found that fear avoidance had a significant indirect effect on the relationships between psychological distress and NS. Conclusions Fear avoidance is related to NS following mTBI. Targeting fear avoidance behaviours and beliefs may represent a treatment target for reducing NS after mTBI.
... Few studies to date have explored the potential predictive value of acute NS following injury, and this symptom arguably warrants further investigation. 4 In the traumatic brain injury (TBI) context, NS generally refers to an increased reactivity to ambient sound 5 and is commonly reported by those diagnosed with an mTBI [6][7][8][9] and more often so among females. 10 More formally, Stansfeld 11 defines NS as a personality trait characterized by an inclination to assess everyday noise negatively, alongside an inability to habituate to such noise. ...
Objective: To describe changes in the prevalence and clinical correlates of noise sensitivity (NS) in mild traumatic brain injury (mTBI) across a 12-month period and to determine whether NS at an early stage of recovery has predictive value for later postconcussive symptoms. Setting: A mixed urban and rural region of New Zealand. Participants: Data for 341 adults (201 males, 140 females; age range from 16 to 91 years) were extracted from a 1-year TBI incidence, and outcomes study was conducted in New Zealand. Design: Secondary analysis of data from a community-based, longitudinal population study of an mTBI incidence cohort collected within 1 week of injury (baseline) and at 1, 6, and 12 months postinjury. Main measures: Measures at baseline (within 2 weeks of the injury) and 1, 6, and 12 months included the Rivermead Post-concussion Symptoms Questionnaire and its NS item, the Hospital Depression and Anxiety Scale, and the computerized CNS-Vital Signs neurocognitive test. Results: NS progressively declined postinjury, from 45% at baseline to 28% at 12 months. In turn, NS showed itself as a significant predictor of future postconcussive symptoms. Conclusion: Taken together with previous research, the findings of the current study indicate that NS may have clinical utility in flagging vulnerability to persistent postconcussive symptoms.
... The current study indicates that social factors such as social position and residential status maybe predictors of NS. Previous studies have indicated that NS can be detrimental to individual health and careers, suggesting a benefit to clinical monitoring [32], especially in socially disadvantaged populations. Future research is also required to determine the relationship between social position, illness, and NS, where both the former and latter may simply be consequences of illness, but still useful markers of social processes. ...
Full-text available
Background: Sensitivity to noise, or nuisance sounds that interrupt relaxation and task-related activities, has been shown to vary significantly across individuals. The current study sought to uncover predictors of noise sensitivity, focussing on possible social and cultural determinants, including social position, education, ethnicity, gender, and the presence of an illness. Method: Data were collected from 746 New Zealand adults residing in 6 areas differentiated by social position. Participants responded to questions probing personal characteristics, noise sensitivity, illness, neighbourhood problems, and noise annoyance. It was hypothesized that those in high-deprivation areas and/or experiencing illness report higher levels of noise sensitivity. Results: Approximately 50 and 10% of the participants reported being moderately or very noise sensitive, respectively. Significant predictors of noise sensitivity included age, length of residence, level of social deprivation, and self-reported illness. Conclusion: There is evidence of social determinants of noise sensitivity, including social position and residential factors.
A concussion occurs when a direct or indirect force is transmitted to the brain, causing a change in brain function. Given that approximately half the brain circuits are involved in vision and the control of eye movements, a concussion frequently results in visual symptoms. Ophthalmic abnormalities are helpful in the assessment of acute concussion, identified by rapid automized naming tasks and eye movement assessments. In particular, convergence, eye‐tracking and the vestibular‐ocular motor screening tool may be used. For patients suffering from post‐concussion syndrome more than three months from the original injury, abnormalities may be found in convergence, accommodation and smooth pursuit. Orthoptic exercises are useful rehabilitation tools to allow patients to return to school, work and recreation. This article provides a brief overview of concussion as it relates to vision and ophthalmic practice.
Photophobia is one of the most common visual complaints stemming from mild traumatic brain injury (mTBI) and causes significant distress. Despite extensive research, the etiology of photophobia is poorly understood, and symptoms are difficult to treat. No randomized controlled trials of treatment of photophobia in patients with mTBI exist; however, tinted glasses have been tried with some success. Targeted therapies involving infusion of calcium gene-related peptide antibody may hold promise.
While there is a long history of rehabilitation for motor deficits following cerebral lesions, less is known about our ability to improve visual deficits. Vision therapy, prisms, occluders, and filters have been advocated for patients with mild traumatic brain injury, on the premise that some of their symptoms may reflect abnormal visual or ocular motor function, but the evidence for their efficacy is modest. For hemianopia, attempts to restore vision have had unimpressive results, though it appears possible to generate blindsight through training. Strategic approaches that train more efficient use of visual search in hemianopia have shown consistent benefit in visual function, while prism aids may help some patients. There are many varieties of alexia. Strategic adaptation of saccades can improve hemianopic alexia, but there has been less work and mixed results for pure alexia, neglect dyslexia, attentional dyslexia, and the central dyslexias. A number of approaches have been tried in prosopagnosia, with recent studies of small groups suggesting that face perception of prosopagnosic subjects can be enhanced through perceptual learning.
Background and objectives: Prior studies have established an association between a history of abuse and the development of migraine. This cross-sectional observational study explored the relationship between self-reported abuse history with migraine-related sensory hypersensitivity symptoms. Methods: In total, 588 adult patients with migraine from the American Registry for Migraine Research completed questionnaires: Generalized Anxiety Disorder-7, Patient Health Questionnaire-2 for depression, Photosensitivity Assessment Questionnaire, Hyperacusis Questionnaire, and Allodynia Symptom Checklist. Using four binary screening questions, patients were asked to self-report if they believed they had suffered emotional, physical, or sexual abuse in their lifetime. Differences in questionnaire scores between groups with and without a history of abuse were determined. Regression models adjusted for age, sex, and basic headache features analyzed the relationship between abuse history and sensory hypersensitivity symptoms. Moderation analysis explored the role of headache frequency in this relationship. Mediation analysis assessed the indirect (Mediated) effect (IE) of abuse on sensory hypersensitivity through depression or anxiety. Additional models analyzed relationships between sensory hypersensitivity symptoms and abuse subtypes or the number of abuse subtypes. Results: Of 588 participants, 222 (38%) reported a history of abuse. Patients with a history of abuse reported statistically significantly greater average headache frequency (7.6 vs. 4.7 days, p = 0.030). Patients with a history of abuse also reported higher average or median questionnaire scores: anxiety (7.6 vs. 4.7, p < 0.001, d = 0.56), depression (1.7 vs. 1.3, p = 0.009, d = 0.24), photophobia (0.54 vs. 0.44, p < 0.001, d = 0.32), hyperacusis (19.6 vs. 14.9, p < 0.001, d = 0.49), ictal allodynia (6.0 vs. 3.0, p < 0.001, d = 0.46), and interictal allodynia (1.0 vs. 0.0, p < 0.001, d = 0.30). After controlling for patient age, sex and years lived with headache, abuse maintained a significant association with every sensory hypersensitivity measure. Headache frequency significantly moderated the relationship between a history of abuse with increased ictal allodynia (p = 0.036). Anxiety significantly mediated the relationships between abuse with photophobia (IE = 0.03, 95% CI = 0.01-0.04), hyperacusis (IE = 1.51, 95% CI = 0.91-2.24), ictal allodynia (IE = 0.02, 95% CI = 0.01-0.04), and interictal allodynia (IE = 0.02, 95% CI = 0.01-0.06). Depression significantly mediated the relationship between abuse with photophobia (IE = 0.02, 95% CI = 0.01-0.03) and with hyperacusis (IE = 0.45, 95% CI = 0.11-0.88). The association between the individual subtypes of abuse and the number of subtypes of abuse with sensory hypersensitivity symptoms varied. Conclusion: A history of abuse is associated with greater migraine-related sensory hypersensitivity symptoms. To reduce the impact of abuse on migraine symptoms, future studies should explore mechanistic connections between abuse and migraine-associated symptoms.
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Many of the more useful and powerful nonparametric procedures may be presented in a unified manner by treating them as rank transformation procedures. Rank transformation procedures are ones in which the usual parametric procedure is applied to the ranks of the data instead of to the data themselves. This technique should be viewed as a useful tool for developing nonparametric procedures to solve new problems.
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This chapter has attempted to bring together the laboratory and field-based techniques currently in use to assess workload. No doubt, many specific procedures of interest to particular applications have been left out of this survey. In no sense is this meant to summarily exclude these from any list of valid workload assessment techniques. In fact, several of these are acknowledged to show considerable promise (e.g., occlusion techniques and respiratory rhythms). They are not discussed here partly because of space limitations and partly because a judgment had to be made concerning the practicality and general applicability of each measure. It is hoped that the inclusion of general references will serve to point the interested reader to the individual techniques not included here. Similarly, a class of techniques frequently used to assess workload was deliberately excluded from this chapter. Task analytic methods, particularly as they are used with computer models of whole missions or operations (see e.g., Lane, Strieb, Glenn, & Wherry, 1981) constitute an important tool for work- load investigations during design and other stages of aircraft and systems development. These techniques, however, are primarily off-line analyses that utilize the kind of laboratory and field data gathered with the techniques such as those described in this chapter. They provide an overall systems answer to the workload question and as such deserve separate treatment from highly specific workload measures. The interested reader is referred to Chubb (1981), Geer (1981), Lane et al. (1981), Parks (1979), and Wherry (1984) for reviews and introductions to some of the modeling techniques used in these areas. swr
Ten university students who had recovered from minor head injury between one and three years previously were given vigilance and memory tests at a simulated altitude of 3,800 metres. Their performance was significantly below that of a matched group of students who had never had a head injury. The finding supports the proposition that even minor head injury has persisting effects, though they may be subtle and only emerge under the effects of stress.
Of 145 patients with concussion from minor head injuries admitted to the Royal Victoria Hospital, Belfast, over one year, 49·0% had no symptoms, 38·9% had between 1 and 6 symptoms, and 2·1% had more than 6 symptoms about six weeks after the accident. There was significant correlation between a high symptom-rate at six weeks and positive neurological signs and symptoms at twenty-four hours. Post-concussion symptoms were more frequent in women, in those injured by falls, and in those who blamed their employers or large impersonal organisations for their accidents. The results suggest that both organic and neurotic factors are involved in the pathogenesis of symptoms at six weeks.
Summarizes clinical and experimental studies on human neuropsychology. Topics include the history of neuropsychology, brain anatomy, elements of neurology, detailed descriptions of the anatomy and functions of each brain lobe, hemispheric asymmetry, and neuropsychological assessment of brain damage. (31 p ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The effect of admission to hospital after a minor head injury on the incidence and duration of post-concussional symptoms was investigated. A total of 114 adults with a minor head injury were randomly allocated to admission for 24 h or to discharge from the accident department. Follow-up was by postal questionnaire. This revealed that 90 per cent of patients suffered symptoms lasting an average of 2 weeks. The patients who were discharged had symptoms that lasted a shorter time. Admission to hospital does not reduce the incidence and severity of symptoms following minor head injuries in adults.
The aetiological factors relevant to the development of post-concussional symptoms are reviewed. From the numerous studies carried out to date, it would appear that both physiogenic and psychogenic influences are important in their genesis. However, where mild-to-moderate injuries are concerned, organic factors are chiefly relevant in the earlier stages, whereas long-continued symptoms are perpetuated by secondary neurotic developments, often of a complex nature.
Seemingly mild head injuries frequently result in persisting postconcussive syndromes. The etiology of these symptoms is often controversial. Neuropsychological, neurophysiological, and neuropathological evidence that brain damage can occur in the absence of gross neurological deficits after mild injuries is reviewed. Direct impact to the head is not required to cause brain injury. Understandably, psychological factors also play a role in post-head-injury disability, but the effect of compensation claims and preinjury psychopathology is often secondary to organic factors. Persons over age 40 or with a history of previous head injury are more vulnerable to protracted symptomatology.
The association between the familial risk for schizophrenia and season of birth was studied in 88 schizophrenic patients. An increased risk for schizophrenia and 'spectrum' disorders was demonstrated among the first-degree relatives of winter and spring-born schizophrenic patients. However, patients with a family history of schizophrenia and 'spectrum' disorders did not differ from patients with no family history with respect to season of birth. Season of birth was unrelated to the sex of the patient, birth order, age at onset, or clinical subtypes (paranoid vs non-paranoid, as defined by the RDC, and 'narrow' vs 'broad', as defined by Taylor & Abrams' 1975 criteria). The morbid-risk data support a 'stress-diathesis' hypothesis whereby environmental factors (in this case a seasonally varying viral insult may be implicated) interact with genetic vulnerability to increase the risk for schizophrenia.